6120K–ATARM– 11-Feb-14
Description
The Atmel SAM7X512/256/128 is a highly-integrated Flash microcontroller based on
the 32-bit ARM® RISC processor. It features 512/256/128 Kbytes of high-speed Flash
and 128/64/32 Kbytes of SRAM, a large set of peripherals, including an 802.3 Ethernet
MAC, and a CAN controller. A complete set of system functions minimizes the number
of external components.
The embedded Flash memory can be programmed in-system via the JTAG-ICE
interface or via a parallel interface on a p roduction programmer prior to mounting. Built-
in lock bits and a security bit protect the firmware from accidental overwrite and
preserve its confidentiality.
The SAM7X512/256/128 system controller includes a reset controller capable of
managing the power-on sequence of the microcontroller and the complete system.
Correct device operation can be monitored by a built-in brownout detector and a
watchdog running off an integrated RC oscillator.
By combining the ARM7TDMI® processor with on-chip Flash and SRAM, and a wide
range of peripheral functions, including USART, SPI, CAN controller, Ethernet MAC,
Timer Counter, RTT and analog-to-digital converters on a monolithic chip, the
SAM7X512/256/128 is a powerful device that provides a flexible, cost-effective solution
to many embedded control applications requiring communication over Ethernet, wired
CAN and ZigBee® wireless networks.
ARM-based Flash MCU
SAM7X512 / SAM7X256 / SAM7X128
DATASHEET
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Features
Incorporates the ARM7TDMI ARM Thumb® Processor
High-performance 32-bit RISC Architecture
High-density 16-bit Instruction Set
Leader in MIPS/Watt
EmbeddedICE™ In-circuit Emulation, Debug Communication Channel Support
Internal High-speed Flash
512 Kbytes (SAM7X512) Organized in Two Banks of 1024 Pages of
256 Bytes (Dual Plane)
256 Kbytes (SAM7X256) Organized in 1024 Pages of 256 Bytes (Single Plane)
128 Kbytes (SAM7X128) Organized in 512 Pages of 256 Byte s (Single Plane)
Single Cycle Access at Up to 30 MHz in Worst Case Conditions
Prefetch Buffer Optimizing Thumb Instruction Execution at Maximum Speed
Page Programming Time: 6 ms, Including Page Auto-erase,
Full Erase Time: 15 ms
10,000 Write Cycles, 10-year Data Retention Capability,
Sector Lock Capabilities, Flash Security Bit
Fast Flash Programming Interface for High Volume Production
Internal High-speed SRAM, Single-cycle Access at Maximum Speed
128 Kbytes (SAM7X512)
64 Kbytes (SAM7X256)
32 Kbytes (SAM7X128)
Memory Controller (MC)
Embedded Flash Controller, Abort Status and Misalignment Detection
Reset Controller (RSTC)
Based on Power-on Reset Cells and Lo w-power Factory-calibrated Brownout Detector
Provides External Reset Signal Shaping and Reset Source Status
Clock Generator (CKGR)
Low-power RC Oscillator, 3 to 20 MHz On-chip Oscillator and one PLL
Power Management Controller (PMC)
Power Optimization Capabilities, Including Slow Clock Mode (Down to 500 Hz) and Idle Mode
Four Programmable External Clock Signals
Advanced Interrupt Controller (AIC)
Individually Maskable, Eight-le vel Priority, Vectored Inte rrupt Sources
Two External Interrupt Sources and One Fast Interrupt Source, Spurious Interrupt Protected
Debug Unit (DBGU)
2-wire UART and Support for Debug Communication Channel interrupt, Programmable ICE Access Prevention
Mode for General Purpose 2-wire UART Serial Communication
Periodic Interval Timer (PIT)
20-bit Programmable Co unter plus 12-bit Interval Counter
Windowed Watchdog (WDT)
12-bit key-protected Programmable Counter
Provides Reset or Interrupt Signals to the System
Counter May Be S topped While the Processor is in Debug State or in Idle Mode
Real-time Timer (RTT)
32-bit Free-running Counter with Alarm
Runs Off the Internal RC Oscillator
Two Parallel Input/Output Controllers (PIO)
Sixty-two Programmable I/O Lines Multiplexed with up to Two Peripheral I/Os
Input Change Interrupt Capability on Each I/O Line
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Individually Programmable Open-drain, Pull-up Resistor and Synchronous Output
Thirteen Peripheral DMA Controller (PDC) Channels
One USB 2.0 Full Speed (12 Mbits per second) Device Port
On-chip Transceiver, 13 52-byte Configurable Integrated FIFOs
One Ethernet MAC 10/100 base-T
Media Independent Interface (MII) or Reduced Media Independent Interface (RMII)
Integrated 28-byte FIFOs and Dedicated DMA Channels for Transmit and Receive
One Part 2.0A and Part 2.0B Compliant CAN Controller
Eight Fully-programmable Message Object Mailboxes, 16-bit Time Stamp Counter
One Synchronous Serial Controller (SSC)
Independent Clock and Frame Sync Signals for Each Receiver and Transmitter
I²S Analog Interface Support, Time Division Multiplex Support
High-speed Continuous Data Stream Capabilities with 32-bit Data Transfer
Two Universal Synchronous/Asynchronous Receiver Transmitters (USART)
Individual Baud Rate Generator, IrDA® Infrared Modulation/Demodulatio n
Support for ISO7816 T0/T1 Smart Card, Hardware Handshaking, RS485 Support
Full Modem Line Supp ort on USART1
Two Master/Slave Serial Peripheral Interfaces (SPI)
8- to 16-bit Programmable Data Length, Four External Peripheral Chip Selects
One Three-channel 16-bit Timer/Counter (TC)
Three External Clock Inputs, Two Multi-purpose I/O Pins per Channel
Double PWM Generation, Capture/Waveform Mode, Up/Down Capability
One Four-channel 16-bit Power Width Modulation Controller (PWMC)
One Two-wire Interface (TWI)
Master Mode Support Only, All Two-wire Atmel EEPROMs and I2C Compatible Devices Supported
One 8-channel 10-bit Analog-to-Digital Converter, Four Channels Multiplexed with Digital I/Os
SAM-BA® Boot Assistance
Default Boot program
Interface with SAM-BA Graphic User Interface
IEEE® 1149.1 JTAG Boundary Scan on All Digital Pins
5V-tolerant I/Os, Including Four High-current Drive I/O lines, Up to 16 mA Each
Power Supplies
Embedded 1.8V Regulator, Drawing up to 100 mA for the Core and External Componen ts
3.3V VDDIO I/O Lines Power Supply, Independent 3.3V VDDFLASH Flash Power Supply
1.8V VDDCORE Core Power Supply with Brownout Detector
Fully Static Operation: Up to 55 MHz at 1.65V and 85°C Worst Case Conditions
Available in 100-lead LQFP Green and 100-ball TFBGA Green Packages
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6120K–ATARM–11-Feb-14
1. Configuration Summary of the SAM7X512/256/128
The SAM7X512, SAM7X256 and SAM7X128 differ only in memory sizes. Table 1-1 summarizes the configurations of the
three devices.
Table 1-1. Configuration Summary
Device Flash Flash Organization SRAM
SAM7X512 512 Kbytes Dual-plane 128 Kbytes
SAM7X256 256 Kbytes Single-plane 64 Kbytes
SAM7X128 128 Kbytes Single-plane 32 Kbytes
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
2. SAM7X512/256/128 Block Diagram
Figure 2-1. SAM7X512/256/128 Block Diagram
TDI
TDO
TMS
TCK
NRST
FIQ
IRQ0-IRQ1
PCK0-PCK3
PMC
Peripheral Bridge
Peripheral DMA
Controller
AIC
PLL
RCOSC
SRAM
128/64/32 Kbytes
ARM7TDMI
Processor
ICE
JTAG
SCAN
JTAGSEL
PIOA
USART0
SSC
Timer Counter
RXD0
TXD0
SCK0
RTS0
CTS0
SPI0_NPCS0
SPI0_NPCS1
SPI0_NPCS2
SPI0_NPCS3
SPI0_MISO
SPI0_MOSI
SPI0_SPCK
Flash
512/256/128
Kbytes
Reset
Controller
DRXD
DTXD
TF
TK
TD
RD
RK
RF
TCLK0
TCLK1
TCLK2
TIOA0
TIOB0
TIOA1
TIOB1
TIOA2
TIOB2
Memory Controller
Abort
Status
Address
Decoder
Misalignment
Detection
PIO
PIO
APB
POR
Embedded
Flash
Controllers
AD0
AD1
AD2
AD3
ADTRG
PLLRC
13 Channels
PDC
PDC
USART1
RXD1
TXD1
SCK1
RTS1
CTS1
DCD1
DSR1
DTR1
RI1
PDC
PDC
PDC
PDC
SPI0
PDC
ADC
ADVREF
PDC
PDC
TC0
TC1
TC2
TWD
TWCK
TWI
OSC
XIN
XOUT
VDDIN
PWMC PWM0
PWM1
PWM2
PWM3
1.8 V
Voltage
Regulator
USB Device
FIFO DDM
DDP
Transceiver
GND
VDDOUT
BOD
VDDCORE
VDDCORE
VDDFLASH
AD4
AD5
AD6
AD7
VDDFLASH
Fast Flash
Programming
Interface
ERASE
PIO
PGMD0-PGMD15
PGMNCMD
PGMEN0-PGMEN1
PGMRDY
PGMNVALID
PGMNOE
PGMCK
PGMM0-PGMM3
VDDIO
TST
DBGU PDC
PDC
PIT
WDT
RTT
System Controller
VDDCORE
CAN CANRX
CANTX
PIO
Ethernet MAC 10/100
ETXCK-ERXCK-EREFCK
ETXEN-ETXER
ECRS-ECOL, ECRSDV
ERXER-ERXDV
ERX0-ERX3
ETX0-ETX3
EMDC
EMDIO
DMA
FIFO
PIOB
SPI1_NPCS0
SPI1_NPCS1
SPI1_NPCS2
SPI1_NPCS3
SPI1_MISO
SPI1_MOSI
SPI1_SPCK
PDC
PDC
SPI1
EF100
SAM-BA
ROM
VDDFLASH
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6120K–ATARM–11-Feb-14
3. Signal Description
Table 3-1. Signal Description List
Signal Name Function Type Active
Level Comments
Power
VDDIN Voltage Regulator and ADC Power
Supply Input Power 3V to 3.6V
VDDOUT Voltage Regulator Output Power 1.85V
VDDFLASH Flash and USB Power Supply Power 3V to 3.6V
VDDIO I/O Lines Power Supply Power 3V to 3.6V
VDDCORE Core Power Supply Power 1.65V to 1.95V
VDDPLL PLL Power 1.65V to 1.95V
GND Ground Ground
Clocks, Osc illators and PLLs
XIN Main Oscillator Input Input
XOUT Main Oscillator Output Output
PLLRC PLL Filter Input
PCK0 - PCK3 Programmable Clock Output Output
ICE and JTAG
TCK Test Clock Input No pull-up resistor
TDI Test Data In Input No pull-up resistor
TDO Test Data Out Output
TMS Test Mode Select Input No pull-up resistor
JTAGSEL JTAG Selection Input Pull-d own resistor(1)
Flash Memory
ERASE Flash and NVM Configuratio n Bits Erase
Command Input High Pull-down resistor(1)
Reset/Test
NRST Microcontroller Reset I/O Low Pull-up resi stor, Open Drain
Output
TST Test Mode Select Input High Pull-down resistor(1)
Debug Unit
DRXD Debug Receive Data Input
DTXD Debug Transmit Data Output
AIC
IRQ0 - IRQ1 External Interrupt Inputs Input
FIQ Fast Interrupt Input Input
PIO
PA0 - PA30 Parallel IO Controller A I/O Pulled-up input at reset
PB0 - PB30 Parallel IO Controller B I/O Pulled-up input at reset
USB Device Port
DDM USB Device Port Data - Analog
DDP USB Device Port Data + Analog
USART
SCK0 - SCK1 Serial Clock I/O
TXD0 - TXD1 Transmit Data I/O
RXD0 - RXD1 Receive Data Input
RTS0 - RTS1 Request To Send Output
CTS0 - CTS1 Clear To Send Input
DCD1 Data Carrier Detect Input
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
DTR1 Data Terminal Ready Output
DSR1 Data Set Ready Input
RI1 Ring Indicator Input
Synchronous Serial Controller
TD Transmit Data Output
RD Receive Data Input
TK Transmit Clock I/O
RK Receive Clock I/O
TF Transmit Frame Sync I/O
RF Receive Frame Sync I/O
Timer/Counter
TCLK0 - TCLK2 External Clock Inputs Input
TIOA0 - TIOA2 I/O Line A I/O
TIOB0 - TIOB2 I/O Line B I/O
PWM Controller
PWM0 - PWM3 PWM Channels Output
Serial Peripheral Interface - SPIx
SPIx_MISO Master In Slave Out I/O
SPIx_MOSI Master Out Slave In I/O
SPIx_SPCK SPI Serial Clock I/O
SPIx_NPCS0 SPI Peripheral Chip Select 0 I/O Low
SPIx_NPCS1-NPCS3 SPI Peripheral Chip Select 1 to 3 Output Low
Two-wire Interface
TWD Two-wire Serial Data I/O
TWCK Two-wire Serial Clock I/O
Analog-to-Digital Converter
AD0-AD3 Analog Inputs Analog Digital pulled-up inputs at reset
AD4-AD7 Analog Inputs Analog Analog Inputs
ADTRG ADC Trigger Input
ADVREF ADC Reference Analog
Fast Flash Program ming Interface
PGMEN0-PGMEN1 Programming Enabling Input
PGMM0-PGMM3 Programming Mode Input
PGMD0-PGMD15 Programming Data I/O
PGMRDY Programming Ready Output High
PGMNVALID Data Direction Output Low
PGMNOE Programming Read Input Low
PGMCK Programming Clock Input
PGMNCMD Programming Command Input Low
CAN Controller
CANRX CAN Input Input
CANTX CAN Output Output
Ethernet MAC 10/100
EREFCK Reference Clo ck Input RMII only
ETXCK Transmit Clock Input MII only
ERXCK Receive Clock Input MII only
ETXEN Transmit Enable Output
ETX0 - ETX3 Transmit Data Output ETX0 - ETX1 only in RMII
Tabl e 3-1. Signal Descripti on List (Continued)
Signal Name Function Type Active
Level Comments
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6120K–ATARM–11-Feb-14
Note: 1. Refer to Section 6. ”I/O Lines Considerations”.
ETXER Transmit Coding Error Output MII only
ERXDV Receive Data Valid Input MII only
ECRSDV Carrier Sense and Data Valid Input RMII only
ERX0 - ERX3 Receive Data Input ERX0 - ERX1 only in RMII
ERXER Receive Error Input
ECRS Carrier Sense Input MII only
ECOL Collision Detected Input MII only
EMDC Management Data Clock Output
EMDIO Management Data Input/Output I/O
EF100 Force 100 Mbits/sec. Output High RMII only
Tabl e 3-1. Signal Descripti on List (Continued)
Signal Name Function Type Active
Level Comments
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6120K–ATARM–11-Feb-14
4. Package
The SAM7X512/256/128 is available in 100-lead LQFP Green and 100-ball TFBGA RoHS-compliant packages.
4.1 100-lead LQFP Package Outline
Figure 4-1 shows the orientation of the 100-lead LQFP package. A detailed mechanical description is given in the
Mechanical Characteristics section.
Figure 4-1. 100-lead LQFP Package Outline (Top View)
4.2 100-lead LQFP Pinout
125
26
50
5175
76
100
Table 4-1. Pinout in 100-lead LQFP Package
1 ADVREF 26 PA18/PGMD6 51 TDI 76 TDO
2 GND 27 PB9 52 GND 77 JTAGSEL
3 AD4 28 PB8 53 PB16 78 TMS
4 AD5 29 PB14 54 PB4 79 TCK
5 AD6 30 PB13 55 PA23/PGMD11 80 PA30
6 AD7 31 PB6 56 PA24/PGMD12 81 PA0/PGMEN0
7 VDDOUT 32 GND 57 NRST 82 PA1/PGMEN1
8 VDDIN 33 VDDIO 58 TST 83 GND
9 PB27/AD0 34 PB5 59 PA25/PGMD13 84 VDDIO
10 PB28/AD1 35 PB15 60 PA26/PGMD14 85 PA3
11 PB29/AD2 36 PB17 61 VDDIO 86 PA2
12 PB30/AD3 37 VDDCORE 62 VDDCORE 87 VDDCORE
13 PA8/PGMM0 38 PB7 63 PB18 88 PA4/PGMNCMD
14 PA9/PGMM1 39 PB12 64 PB19 89 PA5/PGMRDY
15 VDDCORE 40 PB0 65 PB20 90 PA6/PGMNOE
16 GND 41 PB1 66 PB21 91 PA7/PGMNVALID
17 VDDIO 42 PB2 67 PB22 92 ERASE
18 PA10/PGMM2 43 PB3 68 GND 93 DDM
19 PA11/PGMM3 44 PB10 69 PB23 94 DDP
20 PA12/PGMD0 45 PB11 70 PB24 95 VDDFLASH
21 PA13/PGMD1 46 PA19/PGMD7 71 PB25 96 GND
22 PA14/PGMD2 47 PA20/PGMD8 72 PB26 97 XIN/PGMCK
23 PA15/PGMD3 48 VDDIO 73 PA27/PGMD15 98 XOUT
24 PA16/PGMD4 49 PA21/PGMD9 74 PA28 99 PLLRC
25 PA17/PGMD5 50 PA22/PGMD10 75 PA29 100 VDDPLL
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6120K–ATARM–11-Feb-14
4.3 100-ball TFBGA Package Outline
Figure 4-2 shows the orientation of the 100-ball TFBGA package. A detailed mechanical description is given in the
Mechanical Characteristics section of the full datasheet.
Figure 4-2. 100-ball TFBGA Package Outline (Top View)
4.4 100-ball TFBGA Pinout
1
3
4
5
6
7
8
9
10
2
ABCDEFGHJK
TOP VIEW
BALL A1
Pinout in 100-ball TFBGA Package
Pin Signal Name Pin Signal Name Pin Signal Name Pin Signal Name
A1 PA22/PGMD10 C6 PB17 F1 PB21 H6 PA7/PGMNVALID
A2 PA21/PGMD9 C7 PB13 F2 PB23 H7 PA9/PGMM1
A3 PA20/PGMD8 C8 PA13/PGMD1 F3 PB25 H8 PA8/PGMM0
A4 PB1 C9 PA12/PGMD0 F4 PB26 H9 PB29/AD2
A5 PB7 C10 PA15/PGMD3 F5 TCK H10 PLLRC
A6 PB5 D1 PA23/PGMD11 F6 PA6/PGMNOE J1 PA29
A7 PB8 D2 PA24/PGMD12 F7 ERASE J2 PA30
A8 PB9 D3 NRST F8 VDDCORE J3 PA0/PGMEN0
A9 PA18/PGMD6 D4 TST F9 GND J4 PA1/PGMEN1
A10 VDDIO D5 PB19 F10 VDDIN J5 VDDFLASH
B1 TDI D6 PB6 G1 PB22 J6 GND
B2 PA19/PGMD7 D7 PA10/PGMM2 G2 PB24 J7 XIN/PGMCK
B3 PB11 D8 VDDIO G3 PA27/PGMD15 J8 XOUT
B4 PB2 D9 PB27/AD0 G4 TDO J9 GND
B5 PB12 D10 PA11/PGMM3 G5 PA2 J10 VDDPLL
B6 PB15 E1 PA25/PGMD13 G6 PA5/PGMRDY K1 VDDCORE
B7 PB14 E2 PA26/PGMD14 G7 VDDCORE K2 VDDCORE
B8 PA14/PGMD2 E3 PB18 G8 GND K3 DDP
B9 PA16/PGMD4 E4 PB20 G9 PB30/AD3 K4 DDM
B10 PA17/PGMD5 E5 TMS G10 VDDOUT K5 GND
C1 PB16 E6 GND H1 VDDCORE K6 AD7
C2 PB4 E7 VDDIO H2 PA28 K7 AD6
C3 PB10 E8 PB28/AD1 H3 JTAGSEL K8 AD5
C4 PB3 E9 VDDIO H4 PA3 K9 AD4
C5 PB0 E10 GND H5 PA4/PGMNCMD K10 ADVREF
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6120K–ATARM–11-Feb-14
5. Power Considerations
5.1 Power Supplies
The SAM7X512/256/128 has six types of power supply pins and integrates a voltage regulator, allowing the device to b e
supplied with only one voltage. The six power supply pin types are:
VDDIN pin. It powers the voltage regulator and the ADC; voltage ranges from 3.0V to 3.6V, 3.3V nominal. In order
to decrease current consumption, if the voltage regulator and the ADC are not used, VDDIN, ADVREF, AD4, AD5,
AD6 and AD7 should be connected to GND. In this case, VDDOUT should be left unconnected.
VDDOUT pin. It is the output of the 1.8V voltage regulator.
VDDIO pin. It powers the I/O lines; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
VDDFLASH pin. It powers the USB transceivers and a part of the Flash and is required for the Flash to operate
correctly; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
VDDCORE pins. They power the logic of the device; voltage ranges from 1.65V to 1.95V, 1.8V typical. It can be
connected to the VDDOUT pin with decoupling capacitor. VDDCORE is required for the device, including its
embedded Flash, to operate correctly.
VDDPLL pin. It powers the oscillator and the PLL. It can be connected directly to the VDDOUT pin.
No separate ground pins are provided for the different power supplies. Only GND pins are provided and should be
connected as shortly as possible to the system ground plane.
5.2 Power Consumption
The SAM7X512/256/128 has a static current of less than 60 µA on VDDCORE at 25°C, including the RC oscillator, the
voltage regulator and the power-on reset when the brownout detector is deactivated. Activating the brownout detector
adds 28 µA static current.
The dynamic power consumption on VDDCORE is less than 90 mA at full speed when running out of the Flash. Under
the same conditions, the power consumption on VDDFLASH does not exceed 10 mA.
5.3 Voltage Regulator
The SAM7X512/256/128 embeds a voltage regulator that is managed by the System Controller.
In Normal Mode, the voltage regulator consumes less than 100 µA static current and draws 100 mA of output current.
The voltage regulator also has a Low-power Mode. In this mode, it consumes less than 25 µA static current and draws 1
mA of output current.
Adequate output supply decoupling is mandatory for VDDOUT to reduce ripple and avoid oscillations. The best way to
achieve this is to use two capacitors in parallel: one external 470 pF (or 1 nF) NPO capacitor should be connected
between VDDOUT and GND as close to the chip as possible. One external 2.2 µF (or 3.3 µF) X7R capacitor should be
connected between VDDOUT and GND.
Adequate input supply decoupling is mandatory for VDDIN in order to improve startup stability and reduce source voltage
drop. The input decoupling capacitor should be placed close to the chip. For example, two capacitors can be used in
parallel: 100 nF NPO and 4.7 µF X7R.
5.4 Typ ical Powering Schematics
The SAM7X512/256/128 supports a 3.3V single supply mode. The internal regulator input connected to the 3.3V source
and its output feeds VDDCORE and the VDDPLL. Figure 5-1 shows the power schematics to be used for USB bus-
powered systems.
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 5-1. 3.3V System Single Power Supply Schematic
Power Source
ranges
from 4.5V (USB)
to 18V
3.3V
VDDIN
Voltage
Regulator
VDDOUT
VDDIO
DC/DC Converter
VDDCORE
VDDFLASH
VDDPLL
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6120K–ATARM–11-Feb-14
6. I/O Lines Considerations
6.1 JTAG Port Pins
TMS, TDI and TCK are schmitt trigger inputs and are not 5-V tolerant. TMS, TDI and TCK do not integrate a pull-up
resistor.
TDO is an output, driven at up to VDDIO, and has no pull-up resistor.
The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. The JTAGSEL pin integrates
a permanent pull-down resistor of about 15 kΩ to GND.
To eliminate any risk of spuriously entering the JTAG boundary scan mode due to noise on JTAGSEL, it should be tied
externally to GND if boundary scan is not used, or pulled down with an external low-value resistor (such as 1 kΩ) .
6.2 Test Pin
The TST pin is used for manufacturing test or fast programming mode of the SAM7X512/256/128 when asserted high.
The TST pin integrates a permanent pull-down resistor of about 15 kΩ to GND.
To eliminate any risk of entering the test mode due to noise on the TST pin, it should be tied to GND if the FFPI is not
used, or pulled down with an external low-value resistor (such as 1 kΩ)
To enter fast programming mode, the TST pin and the PA0 and PA1 pins should be tied high and PA2 tied to low.
Driving the TST pin at a high level while PA0 or PA1 is driven at 0 leads to unpredictable results.
6.3 Reset Pin
The NRST pin is bidirectional with an open drain output buffer. It is handled by the on-chip reset controller and can be
driven low to provide a reset signal to the external components or asserted low externally to reset the microcontroller.
There is no constraint on the length of the reset pulse, and the reset controller can guarantee a minimum pulse length.
This allows connection of a simple push-button on the NRST pin as system user reset, and the use of the signal NRST to
reset all the components of the system.
The NRST pin integrates a permanent pull-up resistor to VDDIO.
6.4 ERASE Pin
The ERASE pin is used to re-initialize the Flash content and some of its NVM bits. It integrates a permanent pull-down
resistor of about 15 kΩ to GND.
To eliminate any risk of erasing the Flash due to noise on the ERASE pin, it shoul be tied externally to GND, which
prevents erasing the Flash from the applicatiion, or pulled down with an external low-value resistor (such as 1 kΩ) .
This pin is debounced by the RC oscillator to improve the glitch tolerance. When the pin is tied to high during less than
100 ms, ERASE pin is not taken into account. The pin must be tied high during more than 220 ms to perform the re-
initialization of the Flash.
6.5 PIO Controller Lines
All the I/O lines, PA0 to PA30 and PB0 to PB30, are 5V-tolerant and all integrate a programmable pull-up resistor.
Programming of this pull-up resistor is performed independently for each I/O line through the PIO controllers.
5V-tolerant means that the I/O lines can drive voltage level according to VDDIO, but can be driven wit h a voltage of up to
5.5V. However, driving an I/O line with a voltage over VDDIO while the programmable pull-up resistor is enabled will
create a current path through the pull-up resistor from the I/O line to VDDIO. Care should be taken, in particular at reset,
as all the I/O lines default to input with pull-up resistor enabled at reset.
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6120K–ATARM–11-Feb-14
6.6 I/O Lines Current Drawing
The PIO lines PA0 to PA3 are high-drive current capable. Each of these I/O lines can drive up to 16 mA permanently.
The remaining I/O lines can draw only 8 mA.
However, the total current drawn by all the I/O lines cannot exceed 200 mA.
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7. Processor and Architecture
7.1 ARM7TDMI Processor
RISC processor based on ARMv4T Von Neumann architecture
Runs at up to 55 MHz, providing 0.9 MIPS/MHz
Two instruction sets
ARM high-performance 32-bit instruction set
Thumb high code density 16-bit instruction set
Three-stage pipeline architecture
Instruction Fetch (F)
Instruction Decode (D)
Execute (E)
7.2 Debug and Test Features
Integrated embedded in-circuit emulator
Two watchpoint units
Test access port accessible through a JTAG protocol
Debug communication channel
Debug Unit
Two-pin UART
Debug communication channel interrupt handling
Chip ID Register
IEEE1149.1 JTAG Boundary-scan on all digital pins
7.3 Memory Controller
Programmable Bus Arbiter
Handles requests from the ARM7TDMI, the Ethernet MAC and the Peripheral DMA Controller
Address decoder provides selection signals for
Three internal 1 Mbyte memory areas
One 256 Mbyte embedded peripheral area
Abort Status Registers
Source, Type and all parameters of the access leading to an abort are saved
Facilitates debug by detection of bad pointers
Misalignment Detector
Alignment checking of all data accesses
Abort generation in case of misalignment
Remap Command
Remaps the SRAM in place of the embedded non-volatile memory
Allows handling of dynamic exception vectors
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Embedded Flash Controller
Embedded Flash interface, up to three programmable wait states
Prefetch buffer, buffering and anticipating the 16-bit requests, reducing the required wait states
Key-protected program, erase and lock/unlock sequencer
Single command for erasing, programming and locking operations
Interrupt generation in case of forbidden operation
7.4 Peripheral DMA Controller
Handles data transfer between peripherals and memories
Thirteen channels
Two for each USART
Two for the Debug Unit
Two for the Serial Synchronous Controller
Two for each Serial Peripheral Interface
One for the Analog-to-digital Converter
Low bus arbitration overhead
One Master Clock cycle needed for a transfer from memory to peripheral
Two Master Clock cycles needed for a transfer from peripheral to memory
Next Pointer management for reducing interrupt latency requirements
Peripheral DMA Controller (PDC) priority is as follows (from the highest priority to the lowest):
Receive DBGU
Receive USART0
Receive USART1
Receive SSC
Receive ADC
Receive SPI0
Receive SPI1
Transmit DBGU
Transmit USART0
Transmit USART
Transmit SSC
Transmit SPI0
Transmit SPI1
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8. Memories
8.1 SAM7X512
512 Kbytes of dual-plane Flash Memory
2 contiguous banks of 1024 pages of 256 bytes
Fast access time, 30 MHz single-cycle access in Worst Case conditions
Page programming time: 6 ms, including page auto-erase
Page programming without auto-erase: 3 ms
Full chip erase time: 15 ms
10,000 write cycles, 10-year data retention capability
32 lock bits, protecting 32 sectors of 64 pages
Protection Mode to secure contents of the Flash
128 Kbytes of Fast SRAM
Single-cycle access at full speed
8.2 SAM7X256
256 Kbytes of Flash Memory
1024 pages of 256 bytes
Fast access time, 30 MHz single-cycle access in Worst Case conditions
Page programming time: 6 ms, including page auto-erase
Page programming without auto-erase: 3 ms
Full chip erase time: 15 ms
10,000 write cycles, 10-year data retention capability
16 lock bits, each protecting 16 sectors of 64 pages
Protection Mode to secure contents of the Flash
64 Kbytes of Fast SRAM
Single-cycle access at full speed
8.3 SAM7X128
128 Kbytes of Flash Memory
512 pages of 256 bytes
Fast access time, 30 MHz single-cycle access in Worst Case conditions
Page programming time: 6 ms, including page auto-erase
Page programming without auto-erase: 3 ms
Full chip erase time: 15 ms
10,000 write cycles, 10-year data retention capability
8 lock bits, each protecting 8 sectors of 64 pages
Protection Mode to secure contents of the Flash
32 Kbytes of Fast SRAM
Single-cycle access at full speed
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SAM7X Series [DATASHEET]
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Figure 8-1. SAM7X512/256/128 Memory Mapping
0x1000 0000
0x0000 0000
0x0FFF FFFF
0xF000 0000
0xEFFF FFFF
0xFFFF FFFF
256 MBytes
256 MBytes
14 x 256 MBytes
3,584 MBytes
0x000F FFF
0x0010 0000
0x001F FFF
0x0020 0000
0x002F FFF
0x0030 0000
0x003F FFF
0x0040 0000
0x0000 0000
1 MBytes
1 MBytes
1 MBytes
1 MBytes
252 MBytes
0xFFFA 0000
0xFFFA 3FFF
0xFFFA 4000
0xF000 0000
0xFFFB 8000
0xFFFC 0000
0xFFFC 3FFF
0xFFFC 4000
0xFFFC 7FFF
0xFFFD 4000
0xFFFD 7FFF
0xFFFD 3FFF
0xFFFD FFFF
0xFFFE 0000
0xFFFE 3FFF
0xFFFF EFFF
0xFFFF FFFF
0xFFFF F000
0xFFFE 4000
0xFFFE 8000
0xFFFE 7FFF
0xFFFB 4000
0xFFFB 7FFF
0xFFF9 FFFF
0xFFFC FFFF
0xFFFD 8000
0xFFFD BFFF
0xFFFC BFFF
0xFFFC C000
0xFFFB FFFF
0xFFFB C000
0xFFFB BFFF
0xFFFA FFFF
0xFFFB 0000
0xFFFB 3FFF
0xFFFD 0000
0xFFFD C000
0xFFFC 8000
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
16 Kbytes
0x0FFF FFFF
512 Bytes/128 registers
512 Bytes/128 registers
256 Bytes/64 registers
16 Bytes/4 registers
16 Bytes/4 registers
16 Bytes/4 registers
16 Bytes/4 registers
256 Bytes/64 registers
4 Bytes/1 register
512 Bytes/128 registers
512 Bytes/128 registers
0xFFFF F000
0xFFFF F200
0xFFFF F1FF
0xFFFF F3FF
0xFFFF FBFF
0xFFFF FCFF
0xFFFF FEFF
0xFFFF FFFF
0xFFFF F400
0xFFFF FC00
0xFFFF FD0F
0xFFFF FC2F
0xFFFF FC3F
0xFFFF FD4F
0xFFFF FC6F
0xFFFF F5FF
0xFFFF F600
0xFFFF F7FF
0xFFFF F800
0xFFFF FD00
0xFFFF FF00
0xFFFF FD20
0xFFFF FD30
0xFFFF FD40
0xFFFF FD60
0xFFFF FD70
Internal Memories
Undefined
(Abort)
(1) Can be ROM, Flash or SRAM
depending on GPNVM2 and REMAP
Flash before Remap
SRAM after Remap
Internal Flash
Internal SRAM
Internal ROM
Reserved
Boot Memory (1)
Address Memory Space
Internal Memory Mapping Note:
TC0, TC1, TC2
USART0
USART1
PWMC
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
CAN
EMAC
Reserved
TWI
SSC
SPI0
SPI1
UDP
ADC
AIC
DBGU
PIOA
Reserved
PMC
MC
WDT
PIT
RTT
RSTC
VREG
PIOB
Peripheral Mapping
System Controller Mapping
Internal Peripherals
Reserved
SYSC
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8.4 Memory Mapping
8.4.1 Internal SRAM
The SAM7X512 embeds a high-speed 128-Kbyte SRAM bank.
The SAM7X256 embeds a high-speed 64-Kbyte SRAM bank.
The SAM7X128 embeds a high-speed 32-Kbyte SRAM bank.
After reset and until the Remap Command is performed, the SRAM is only accessible at address 0x0020 0000. After
Remap, the SRAM also becomes available at address 0x0.
8.4.2 Internal ROM
The SAM7X512/256/128 embeds an Internal ROM. At any time, the ROM is mapped at address 0x30 0000. The ROM
contains the FFPI and the SAM-BA program.
8.4.3 Internal Flash
The SAM7X512 features two banks (dual plane) of 256 Kbytes of Flash.
The SAM7X256 features one bank (single plane) of 256 Kbytes of Flash.
The SAM7X128 features one bank (single plane) of 128 Kbytes of Flash.
At any time, the Flash is mapped to address 0x0010 0000. It is also accessible at address 0x0 after the reset, if GPNVM
bit 2 is set and before the Remap Command.
A general purpose NVM (GPNVM) bit is used to boot either on the ROM (default) or from the Flash.
This GPNVM bit can be cleared or set respectively through the commands “Clear General-purpose NVM Bit” and “Set
General-purpose NVM Bit” of the EFC User Interface.
Setting the GPNVM Bit 2 selects the boot from the Flash. Asserting ERASE clears the GPNVM Bit 2 and thus selects the
boot from the ROM by default.
Figure 8-2. Internal Memory Mapping with GPNVM Bit 2 = 0 (default)
256M Bytes
ROM Before Remap
SRAM After Remap
Undefined Areas
(Abort)
0x000F FFFF
0x001F FFFF
0x002F FFFF
0x0FFF FFFF
1 M Bytes
1 M Bytes
1 M Bytes
252 M Bytes
Internal FLASH
Internal SRAM
0x0000 0000
0x0010 0000
0x0020 0000
0x0030 0000 Internal ROM
0x003F FFFF
0x0040 0000
1 M Bytes
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SAM7X Series [DATASHEET]
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Figure 8-3. Internal Memory Mapping with GPNVM Bit 2 = 1
8.5 Embedded Flash
8.5.1 Flash Overview
The Flash of the SAM7X512 is organized in two banks (dual plane) of 1024 pages of 256 bytes. The 524,288 bytes
are organized in 32-bit words.
The Flash of the SAM7X256 is organized in 1024 pages of 256 bytes (single plane). It reads as 65,536 32-bit
words.
The Flash of the SAM7X128 is organized in 512 p ages of 256 bytes (single plane). It reads as 32,768 32-bit words.
The Flash contains a 256-byte write buffer, accessible through a 32-bit interface.
The Flash benefits from the integration of a power reset cell and from the brownout detector. This prevents code
corruption during power supply changes, even in the worst conditions.
When Flash is not used (read or write access), it is automatically placed into standby mode.
8.5.2 Embedded Flash Controller
The Embedded Flash Controller (EFC) manages accesses performed by the masters of the system. It enables reading
the Flash and writing the write buffer. It also contains a User Interface, mapped within the Memory Controller on the APB.
The User Interface allows:
programming of the access parameters of the Flash (number of wait states, timings, etc.)
starting commands such as full erase, page erase, page program, NVM bit set, NVM bit clear, etc.
getting the end status of the last command
getting error status
programming interrupts on the end of the last commands or on errors
The Embedded Flash Controller also provides a dual 32-bit Prefetch Buffer that optimizes 16-bit access to the Flash.
This is particularly efficient when the processor is running in Thumb mode.
Two EFCs are embedded in the SAM7X512 to control each bank of 256 KBytes. Dual-plane organization allows
concurrent read and program functionality. Read from one memory plane may be performed even while program or
erase functions are being executed in the other memory plane.
One EFC is embedded in the SAM7X256/128 to control the single plane of 256/128 KBytes.
256M Bytes
Flash Before Remap
SRAM After Remap
Undefined Areas
(Abort)
0x000F FFFF
0x001F FFFF
0x002F FFFF
0x0FFF FFFF
1 M Bytes
1 M Bytes
1 M Bytes
252 M Bytes
Internal FLASH
Internal SRAM
0x0000 0000
0x0010 0000
0x0020 0000
0x0030 0000 Internal ROM
0x003F FFFF
0x0040 0000
1 M Bytes
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8.5.3 Lock Regions
8.5.3.1 SAM7X512
Two Embedded Flash Controllers each manage 16 lock bits to protect 16 regions of the flash against inadvertent flash
erasing or programming commands. The SAM7X512 contains 32 lock regions and each lock region contains 64 pages of
256 bytes. Each lock region has a size of 16 Kbytes.
If a locked-region’s erase or program command occurs, the command is aborted and the EFC trigs an interrupt.
The 32 NVM bits are software programmable through both of the EFC User Interfaces. The command “Set Lock Bit”
enables the protection. The command “Clear Lock Bit” unlocks the lock region.
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.
8.5.3.2 SAM7X256
The Embedded Flash Controller manages 16 lock bits to protect 16 regions of the flash a gainst inadvertent flash erasing
or programming commands. The SAM7X256 contains 16 lock regions and each lock region contains 64 pages of 256
bytes. Each lock region has a size of 16 Kbytes.
If a locked-region’s erase or program command occurs, the command is aborted and the EFC trigs an interrupt.
The 16 NVM bits are software programmable through the EFC User Interface. The command “Set Lock Bit” enables the
protection. The command “Clear Lock Bit” unlocks the lock region.
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.
8.5.3.3 SAM7X128
The Embedded Flash Controller manages 8 lock bits to protect 8 regions of the flash against inadvertent flash erasing or
programming commands. The SAM7X128 contains 8 lock regions and each lock region contains 64 pages of 256 bytes.
Each lock region has a size of 16 Kbytes.
If a locked-region’s erase or program command occurs, the command is aborted and the EFC trigs an interrupt.
The 8 NVM bits are software programmable through the EFC User Interface. The command “Set Lock Bit” enables the
protection. The command “Clear Lock Bit” unlocks the lock region.
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.
8.5.4 Security Bit Feature
The SAM7X512/256/128 features a security bit, based on a specific NVM-Bit. When the security is enabled, any access
to the Flash, either through the ICE interface or through the Fast Flash Programmin g Interface, is forbidden. This ensures
the confidentiality of the code programmed in the Flash.
This security bit can only be enabled, through the Command “Set Security Bit” of the EFC User Interface. Disabling the
security bit can only be achieved by asserting the ERASE pin at 1, and after a full flash erase is performed. When the
security bit is deactivated, all accesses to the flash are permitted.
It is important to note that the assertion of the ERASE pin should always be longer than 220 ms.
As the ERASE pin integrates a permanent pull-down, it can be left unconnected during normal operation. However, it is
safer to connect it directly to GND for the final application.
8.5.5 Non-volatile Brownout Detector Control
Two general purpose NVM (GPNVM) bits are used for controlling the brownout detector (BOD), so that even after a
power loss, the brownout detector operations remain in their state.
These two GPNVM bits can be cleared or set respectively through the commands “Clear General-purpo se NVM Bit” and
“Set General-purpose NVM Bit” of the EFC User Interface.
GPNVM Bit 0 is used as a brownout detector enable bit. Setting the GPNVM Bit 0 enables the BOD, clearing it
disables the BOD. Asserting ERASE clears the GPNVM Bit 0 and thus disables the brownout detector by default.
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The GPNVM Bit 1 is used as a brownout reset enable signal for the reset controller. Setting the GPNVM Bit 1
enables the brownout reset when a brownout is detected, Clearing the GPNVM Bit 1 disables the brownout reset.
Asserting ERASE disables the brownout reset by default.
8.5.6 Calibration Bits
Eight NVM bits are used to calibrate the brownout detector and the voltage regulator. These bits are factory configured
and cannot be changed by the user. The ERASE pin has no effect on the calibration bits.
8.6 Fast Flash Programming Interface
The Fast Flash Programming Interface allows programming the device through either a serial JTAG interface or through
a multiplexed fully-handshaked parallel port. It allows gang-programming with market-standard industrial programmers.
The FFPI supports read, page program, page erase, full erase, lock, unlock and protect commands.
The Fast Flash Programming Interface is enabled and the Fa st Programming Mode is entered when the TST pin and the
PA0 and PA1 pins are all tied high.
8.7 SAM-BA Boot Assistant
The SAM-BA Boot Assistant is a default Boot Program that provides an easy way to program in-situ the on-chip Flash
memory.
The SAM-BA Boot Assistant supports serial communication via the DBGU or the USB Device Port.
Communication via the DBGU supports a wide range of crystals from 3 to 20 MHz via software auto-detection.
Communication via the USB Device Port is limited to an 18.432 MHz crystal.
The SAM-BA Boot provides an interface with SAM-BA Graphic User Interface (GUI).
The SAM-BA Boot is in ROM and is mapped at address 0x0 when the GPNVM Bit 2 is set to 0.
When GPNVM bit 2 is set to 1, the device boots from the Flash.
When GPNVM bit 2 is set to 0, the device boots from ROM (SAM-BA).
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9. System Controller
The System Controller manages all vital blocks of the microcontroller: interrupts, clocks, power, time, debug and reset.
The System Controller peripherals are all mapped to the highest 4 Kbytes of address space, between addresses 0xFFFF
F000 and 0xFFFF FFFF.
Figure 9-1 on page 24 shows the System Controller Block Diagram.
Figure 8-1 on page 18 shows the mapping of the User Interface of the System Controller peripherals. Note that the
Memory Controller configuration user interface is also mapped within this address space.
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SAM7X Series [DATASHEET]
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Figure 9-1. System Controller Bloc k D iagram
NRST
SLCK
Advanced
Interrupt
Controller
Real-Time
Timer
Periodic
Interval
Timer
Reset
Controller
PA0-PA30
periph_nreset
System Controller
Watchdog
Timer
wdt_fault
WDRPROC
PIO
Controller
POR
BOD
RCOSC
gpnvm[0]
cal
en
Power
Management
Controller
OSC
PLL
XIN
XOUT
PLLRC
MAINCK
PLLCK
pit_irq
MCK
proc_nreset
wdt_irq
periph_irq{2-3]periph_nreset
periph_clk[2..18]
PCK
MCK
pmc_irq
UDPCK
nirq
nfiq
rtt_irq
Embedded
Peripherals
periph_clk[2-3]
pck[0-3]
in
out
enable
ARM7TDMI
SLCK
SLCK
irq0-irq1
fiq
irq0-irq1
fiq
periph_irq[4..19]
periph_irq[2..19]
int
int
periph_nreset
periph_clk[4..19]
Embedded
Flash
flash_poe
jtag_nreset
flash_poe
gpnvm[0..2]
flash_wrdis
flash_wrdis
proc_nreset
periph_nreset
dbgu_txd
dbgu_rxd
pit_irq
rtt_irq
dbgu_irq
pmc_irq
rstc_irq
wdt_irq
rstc_irq
efc_irq
SLCK
gpnvm[1]
Boundary Scan
TAP Controller
jtag_nreset
power_on_reset
debug
PCK
debug
idle
debug
Memory
Controller
MCK
proc_nreset
bod_rst_en
proc_nreset
power_on_reset
periph_nreset
idle
Debug
Unit
dbgu_irq
MCK
dbgu_rxd
periph_nreset force_ntrst
dbgu_txd
USB Device
Port
UDPCK
periph_nreset
periph_clk[11]
periph_irq[11]
usb_suspend
usb_suspend
Voltage
Regulator
standby
Voltage
Regulator
Mode
Controller
security_bit
cal
power_on_reset
force_ntrst
cal
PB0-PB30
efc_irq
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9.1 Reset Controller
Based on one power-on reset cell and one brownout detector
Status of the last reset, either Power-up Reset, Software Reset, User Reset, Watchdog Reset, Brownout Reset
Controls the internal resets and the NRST pin output
Allows to shape a signal on the NRST line, guaranteeing that the length of the pulse meets any requirement.
9.1.1 Brownout Detector and Power-on Reset
The SAM7X512/256/128 embeds one brownout detection circuit and a power-on reset cell. The power-on reset is
supplied with and monitors VDDCORE.
Both signals are provided to the Flash to prevent any code corruption during power-up or power-down sequences or if
brownouts occur on the power supplies.
The power-on reset cell has a limited-accuracy threshold at around 1.5V. Its output remains low during power-up until
VDDCORE goes over this voltage level. This signal goes to the reset controller and allows a full re-initialization of the
device.
The brownout detector monitors the VDDCORE and VDDFLASH levels during operation by comparing them to a fixed
trigger level. It secures system operations in the most difficult environments and prevents code corruption in case of
brownout on the VDDCORE or VDDFLASH.
When the brownout detector is enabled and VDDCORE decreases to a value below the trigger level (Vbot18-, defined as
Vbot18 - hyst/2), the brownout output is immediately activated.
When VDDCORE increases above the trigger level (Vbot18+, defined as Vbot18 + hyst/2), the reset is released. The
brownout detector only detects a drop if the voltage on VDDCORE stays below the threshold voltage for longer than
about 1µs.
The VDDCORE threshold voltage has a hysteresis of about 50 mV, to ensure spike free brownout detection. The typical
value of the brownout detector threshold is 1.68V with an accuracy of ± 2% and is factory calibrated.
When the brownout detector is enabled and VDDFLASH decreases to a value below the trigger level (Vbot33-, defined
as Vbot33 - hyst/2), the brownout output is immediately activated.
When VDDFLASH increases above the trigger level (Vbot33+, defined as Vbot33 + hyst/2), the reset is released. The
brownout detector only detects a drop if the voltage on VDDCORE stays below the threshold voltage for longer than
about 1µs.
The VDDFLASH threshold voltage has a hysteresis of about 50 mV, to ensure spike free brownout detection. The typical
value of the brownout detector threshold is 2.80V with an accuracy of ± 3.5% and is factory calibrated.
The brownout detector is low-power, as it consumes less than 28 µA static current. However, it can be deactivated to
save its static current. In this case, it consumes less than 1µA. The deactivation is configured through the GPNVM bit 0 of
the Flash.
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9.2 Clock Generator
The Clock Generator embeds one low-power RC Oscillator, one Main Oscillator and one PLL with the following
characteristics:
RC Oscillator ranges between 22 KHz and 42 KHz
Main Oscillator frequency ranges between 3 and 20 MHz
Main Oscillator can be bypassed
PLL output ranges between 80 and 200 MHz
It provides SLCK, MAINCK and PLLCK.
Figure 9-2. Clock Generator Block Diagram
Embedded
RC
Oscillator
Main
Oscillator
PLL and
Divider
Clock Generator
Power
Management
Controller
XIN
XOUT
PLLRC
Slow Clock
SLCK
Main Clock
MAINCK
PLL Clock
PLLCK
Control
Status
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9.3 Power Management Controller
The Power Management Controller uses the Clock Generator outputs to provide:
the Processor Clock PCK
the Master Clock MCK
the USB Clock UDPCK
all the peripheral clocks, independently controllable
four programmable clock outputs
The Master Clock (MCK) is programmable from a few hundred Hz to the maximum operating frequency of the device.
The Processor Clock (PCK) switches off when entering processor idle mode, thus allowing reduced power consumption
while waiting for an interrupt.
Figure 9-3. Power Management Controller Block Diagram
9.4 Advanced Interrupt Controller
Controls the interrupt lines (nIRQ and nFIQ) of an ARM Processor
Individually maskable and vectored interrupt sources
Source 0 is reserved for the Fast Interrupt Input (FIQ)
Source 1 is reserved for system peripherals (RTT, PIT, EFC, PMC, DBGU, etc.)
Other sources control the peripheral interrupts or external interrupts
Programmable edge-triggered or level-sensitive internal sources
Programmable positive/negative edge-triggered or high/low level-sensitive external sources
8-level Priority Controller
Drives the normal interrupt nIRQ of the processor
Handles priority of the interrupt sources
Higher priority interrupts can be served during service of lower priority interrupt
Vectoring
Optimizes interrupt service routine branch and execution
One 32-bit vector register per interrupt source
Interrupt vector register reads the corresponding current interrupt vector
MCK
periph_clk[2..18]
int
UDPCK
SLCK
MAINCK
PLLCK Prescaler
/1,/2,/4,...,/64
PCK
Processor
Clock
Controller
Idle Mode
Master Clock Controller
Peripherals
Clock Controller
ON/OFF
USB Clock Controller
ON/OFF
SLCK
MAINCK
PLLCK Prescaler
/1,/2,/4,...,/64
Programmable Clock Controller
PLLCK Divider
/1,/2,/4
pck[0..3]
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Protect Mode
Easy debugging by preventing automatic operations
Fast Forcing
Permits redirecting any interrupt source on the fast interrupt
General Interrupt Mask
Provides processor synchronization on events without triggering an interrupt
9.5 Debug Unit
Comprises:
One two-pin UART
One Interface for the Debug Communication Channel (DCC) support
One set of Chip ID Registers
One Interface providing ICE Access Prevention
Two-pin UART
USART-compatible User Interface
Programmable Baud Rate Generator
Parity, Framing and Overrun Error
Automatic Echo, Local Loopback and Remote Loopback Channel Modes
Debug Communication Channel Support
Offers visibility of COMMRX and COMMTX signals from the ARM Processor
Chip ID Registers
Identification of the device revision, sizes of the embedded memories, set of peripherals
Chip ID is 0x275C 0A40 (MRL A) for SAM7X512
Chip ID is 0x275B 0940 (MRL A or B) for SAM7X256
Chip ID is 0x275B 0942 (MRL C) for SAM7X256
Chip ID is 0x275A 0740 (MRL A or B) for SAM7X128
Chip ID is 0x275A 0742 (MRL C) for SAM7X128
9.6 Periodic Interval Timer
20-bit programmable counter plus 12-bit interval counter
9.7 Watchdog Timer
12-bit key-protected Programmable Counter running on prescaled SLCK
Provides reset or interrupt signals to the system
Counter may be stopped while the processor is in debug state or in idle mode
9.8 Real-time Ti mer
32-bit free-running counter with alarm running on prescaled SLCK
Programmable 16-bit prescaler for SLCK accuracy compensation
9.9 PIO Controllers
Two PIO Controllers, each controlling 31 I/O lines
Fully programmable through set/clear registers
Multiplexing of two peripheral functions per I/O line
For each I/O line (whether assigned to a peripheral or used as general-purpose I/O)
Input change interrupt
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Half a clock period glitch filter
Multi-drive option enables driving in open drain
Programmable pull-up on each I/O line
Pin data status register, supplies visibility of the level on the pin at any time
Synchronous output, provides Set and Clear of several I/O lines in a single write
9.10 Voltage Regulator Controller
The purpose of this controller is to select the Power Mode of the Voltage Regulator between Normal Mode (bit 0 is
cleared) or Standby Mode (bit 0 is set).
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10. Peripherals
10.1 User Interface
The User Peripherals are mapped in the 256 Mbytes of address space between 0xF000 0000 and 0xFFFF EFFF. Each
peripheral is allocated 16 Kbytes of address space.
A complete memory map is provided in Figure 8-1 on page 18.
10.2 Peripheral Identifiers
The SAM7X512/256/128 embeds a wide range of peripherals. Table 10-1 defines the Peripheral Identifiers of the
SAM7X512/256/128. Unique peripheral identifiers are defined for both the Advanced Interrupt Controller and the Power
Management Controller.
Note: 1. Setting SYSC and ADC bits in the clock set/clear registers of the PMC has no ef fect. The System Controller
and ADC are continuously clocked.
Table 10-1. Peripheral Identifiers
Peripheral ID Peripheral Mnemonic Peripheral Name External
Interrupt
0 AIC Advanced Interrupt Controller FIQ
1 SYSC(1) System Controller
2 PIOA Parallel I/O Controller A
3 PIOB Parallel I/O Controller B
4 SPI0 Serial Peripheral Interface 0
5 SPI1 Serial Peripheral Interface 1
6 US0 USART 0
7 US1 USART 1
8 SSC Synchronous Serial Controller
9 TWI Two-wire Interface
10 PWMC Pulse Width Modulation Controller
11 UDP USB Device Port
12 TC0 Timer/Counter 0
13 TC1 Timer/Counter 1
14 TC2 Timer/Counter 2
15 CAN CAN Controller
16 EMAC Ethernet MAC
17 ADC(1) Analog-to Digital Converter
18 - 29 Reserved
30 AIC Advanced Interrupt Controller IRQ0
31 AIC Advanced Interrupt Controller IRQ1
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10.3 Peripheral Multiplexing on PIO Lines
The SAM7X512/256/128 features two PIO controllers, PIOA and PIOB, that multiplex the I/O lines of the peripheral set.
Each PIO Controller controls 31 lines. Each line can be assigned to one of two peripheral functions, A or B. Some of
them can also be multiplexed with the analog inputs of the ADC Controller.
Table 10-2 on page 32 and Table 10-3 on page 33 defines how the I/O lines of the peripherals A, B or the analog inputs
are multiplexed on the PIO Controller A and PIO Controller B. The two columns “Function” and “Comments” have been
inserted for the user’s own comments; they may be used to track how pins are defined in an application.
Note that some peripheral functions that are output only, may be duplicated in the table.
At reset, all I/O lines are automatically configured as input with the programmable pull-up enabled, so that the device is
maintained in a static state as soon as a reset is detected.
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10.4 PIO Controller A Multiplexing
Table 10-2. Multiplexing on PIO Controller A
PIO Controller A Application Usage
I/O Line Peripheral A Peripheral B Comments Function Comments
PA0 RXD0 High-drive
PA1 TXD0 High-drive
PA2 SCK0 SPI1_NPCS1 High-drive
PA3 RTS0 SPI1_NPCS2 High-drive
PA4 CTS0 SPI1_NPCS3
PA5 RXD1
PA6 TXD1
PA7 SCK1 SPI0_NPCS1
PA8 RTS1 SPI0_NPCS2
PA9 CTS1 SPI0_NPCS3
PA10 TWD
PA11 TWCK
PA12 SPI_NPCS0
PA13 SPI0_NPCS1 PCK1
PA14 SPI0_NPCS2 IRQ1
PA15 SPI0_NPCS3 TCLK2
PA16 SPI0_MISO
PA17 SPI0_MOSI
PA18 SPI0_SPCK
PA19 CANRX
PA20 CANTX
PA21 TF SPI1_NPCS0
PA22 TK SPI1_SPCK
PA23 TD SPI1_MOSI
PA24 RD SPI1_MISO
PA25 RK SPI1_NPCS1
PA26 RF SPI1_NPCS2
PA27 DRXD PCK3
PA28 DTXD
PA29 FIQ SPI1_NPCS3
PA30 IRQ0 PCK2
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10.5 PIO Controller B Multiplexing
Table 10-3. Multiplexing on PIO Controller B
PIO Controller B Application Usage
I/O Line Peripheral A Peripheral B Comments Function Comments
PB0 ETXCK/EREFCK PCK0
PB1 ETXEN
PB2 ETX0
PB3 ETX1
PB4 ECRS
PB5 ERX0
PB6 ERX1
PB7 ERXER
PB8 EMDC
PB9 EMDIO
PB10 ETX2 SPI1_NPCS1
PB11 ETX3 SPI1_NPCS2
PB12 ETXER TCLK0
PB13 ERX2 SPI0_NPCS1
PB14 ERX3 SPI0_NPCS2
PB15 ERXDV/ECRSDV
PB16 ECOL SPI1_NPCS3
PB17 ERXCK SPI0_NPCS3
PB18 EF100 ADTRG
PB19 PWM0 TCLK1
PB20 PWM1 PCK0
PB21 PWM2 PCK1
PB22 PWM3 PCK2
PB23 TIOA0 DCD1
PB24 TIOB0 DSR1
PB25 TIOA1 DTR1
PB26 TIOB1 RI1
PB27 TIOA2 PWM0 AD0
PB28 TIOB2 PWM1 AD1
PB29 PCK1 PWM2 AD2
PB30 PCK2 PWM3 AD3
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10.6 Ethernet MAC
DMA Master on Receive and Transmit Channels
Compatible with IEEE Standard 802.3
10 and 100 Mbit/s operation
Full- and half-duplex operation
Statistics Counter Registers
MII/RMII interface to the physical layer
Interrupt generation to signal receive and transmit completion
28-byte transmit FIFO and 28-byte receive FIFO
Automatic pad and CRC generation on transmitted frames
Automatic discard of frames received with errors
Address checking logic supports up to four specific 48-bit addresses
Support Promiscuous Mode where all valid received frames are copied to memory
Hash matching of unicast and multicast destination addresses
Physical layer management through MDIO interface
Half-duplex flow control by forcing collisions on incoming frames
Full-duplex flow control with recognition of incoming pause frames
Support for 802.1Q VLAN tagging with recognition of incoming VLAN and priority tagged frames
Multiple buffers per receive and transmit frame
Jumbo frames up to 10240 bytes supported
10.7 Serial Peripheral Interface
Supports communication with external serial devices
Four chip selects with external decoder allow communication with up to 15 peripherals
Serial memories, such as DataFlash® and 3-wire EEPROMs
Serial peripherals, such as ADCs, DACs, LCD Controllers, CAN Controllers and Sensors
External co-processors
Master or slave serial peripheral bus interface
8- to 16-bit programmable data length per chip select
Programmable phase and polarity per chip select
Programmable transfer delays per chip select, between consecutive transfers and between clock and data
Programmable delay between consecutive transfers
Selectable mode fault detection
Maximum frequency at up to Master Clock
10.8 Two-wire Interface
Master Mode only
Compatibility with I2C compatible devices (refer to the TWI section of the datasheet)
One, two or three bytes internal address registers for easy Serial Memory access
7-bit or 10-bit slave addressing
Sequential read/write operations
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10.9 USART
Programmable Baud Rate Generator
5- to 9-bit full-duplex synchronous or asynchronous serial communications
1, 1.5 or 2 stop bits in Asynchronous Mode
1 or 2 stop bits in Synchronous Mode
Parity generation and error detection
Framing error detection, overrun error detection
MSB or LSB first
Optional break generation and detection
By 8 or by 16 over-sampling receiver frequency
Hardware handshaking RTS - CTS
Modem Signals Management DTR-DSR-DCD-RI on USART1
Receiver time-out and transmitter timeguard
Multi-drop Mode with address generation and detection
RS485 with driver control signal
ISO7816, T = 0 or T = 1 Protocols for interfacing with smart cards
NACK handling, error counter with repetition and iteration limit
IrDA modulation and demodulation
Communication at up to 115.2 Kbps
Test Modes
Remote Loopback, Local Loopback, Automatic Echo
10.10 Serial Synchronous Controller
Provides serial synchronous communication links used in audio and telecom applications
Contains an independent receiver and transmitter and a common clock divider
Offers a configurable frame sync and data length
Receiver and transmitter can be programmed to start automatically or on detection of different event on the frame
sync signal
Receiver and transmitter include a data signal, a clock signal and a frame synchronization signal
10.11 T imer Counter
Three 16-bit Timer Counter Channels
Two output compare or one input capture per channel
Wide range of functions including:
Frequency measurement
Event counting
Interval measurement
Pulse generation
Delay timing
Pulse Width Modulation
Up/down capabilities
Each channel is user-configurable and contains:
Three external clock inputs
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Five internal clock inputs, as defined in Table 10-4
Two multi-purpose input/output signals
Two global registers that act on all three TC channels
10.12 Pulse Width Modulation Controller
Four channels, one 16-bit counter per channel
Common clock generator, providing thirteen different clocks
One Modulo n counter providing eleven clocks
Two independent linear dividers working on modulo n counter outputs
Independent channel programming
Independent enable/disable commands
Independent clock selection
Independent period and duty cycle, with double buffering
Programmable selection of the output waveform polarity
Programmable center or left aligned output waveform
10.13 USB Device Port
USB V2.0 full-speed compliant,12 Mbits per second
Embedded USB V2.0 full-speed transceiver
Embedded 1352-byte dual-port RAM for endpoints
Six endpoints
Endpoint 0: 8 bytes
Endpoint 1 and 2: 64 bytes ping-pong
Endpoint 3: 64 bytes
Endpoint 4 and 5: 256 bytes ping-pong
Ping-pong Mode (two memory banks) for bulk endpoints
Suspend/resume logic
10.14 CAN Controller
• Fully compliant with CAN 2.0A and 2.0B
• Bit rates up to 1Mbit/s
• Eight object oriented mailboxes each with the following properties:
CAN Specification 2.0 Part A or 2.0 Part B Programmable for each Message
Object configurable to receive (with overwrite or not) or transmit
Local tag and mask filters up to 29-bit identifier/channel
32-bit access to data registers for each mailbox data object
Uses a 16-bit time stamp on receive and transmit message
Hardware concatenation of ID unmasked bitfields to speedup family ID processing
Table 10-4. Timer Counter Clocks Assignment
TC Clock input Clock
TIMER_CLOCK1 MCK/2
TIMER_CLOCK2 MCK/8
TIMER_CLOCK3 MCK/32
TIMER_CLOCK4 MCK/128
TIMER_CLOCK5 MCK/1024
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16-bit internal timer for time stamping and network synchronization
Programmable reception buffer length up to 8 mailbox objects
Priority management between transmission mailboxes
Autobaud and listening mode
Low power mode and programmable wake-up on bus activity or by the application
Data, remote, error and overload frame handling
10.15 Analog-to-Digital Converter
8-channel ADC
10-bit 384 K samples/sec. Successive Approximation Register ADC
±2 LSB Integral Non Linearity, ±1 LSB Differential Non Linearity
Integrated 8-to-1 multiplexer, offering eight independent 3.3V analog inputs
External voltage reference for better accuracy on low voltage inputs
Individual enable and disable of each channel
Multiple trigger sources
Hardware or software trigger
External trigger pin
Timer Counter 0 to 2 outputs TIOA0 to TIOA2 trigger
Sleep Mode and conversion sequencer
Automatic wakeup on trigger and back to sleep mode after conversions of all enabled channels
Four of eight analog inputs shared with digital signals
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11. ARM7TDMI Processor Overview
11.1 Overview
The ARM7TDMI core executes both the 32-bit ARM and 16-bit Thumb instruction sets, allowing the user to trade off
between high performance and high code density.The ARM7TDMI processor implements Von Neuman architecture,
using a three-stage pipeline consisting of Fetch, Decode, and Execute stages.
The main features of the ARM7tDMI processor are:
ARM7TDMI Based on ARMv4T Architecture
Two Instruction Sets
ARM High-performance 32-bit Instruction Set
Thumb High Code Density 16-bit Instruction Set
Three-Stage Pipeline Architecture
Instruction Fetch (F)
Instruction Decode (D)
Execute (E)
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11.2 ARM7TDMI Processor
For further details on ARM7TDMI, refer to the following ARM documents:
ARM Architecture Reference Manual (DDI 0100E)
ARM7TDMI Technical Reference Manual (DDI 0210B)
11.2.1 Instruction Type
Instructions are either 32 bits long (in ARM state) or 16 bits long (in THUMB state).
11.2.2 Data Type
ARM7TDMI supports byte (8-bit), half-word (16-bit) and word (32-bit) data types. Words must be aligned to four-byte
boundaries and half words to two-byte boundaries.
Unaligned data access behavior depends on which instruction is used where.
11.2.3 ARM7TDMI Operating Mode
The ARM7TDMI, based on ARM architecture v4T, supports seven processor modes:
User: The normal ARM program execution state
FIQ: Designed to support high-speed data transfer or channel process
IRQ: Used for general-purpose interrupt handling
Supervisor: Protected mode for the operating system
Abort mode: Implements virtual memory and/or memory protection
System: A privileged user mode for the operating system
Undefined: Supports software emulation of hardware coprocessors
Mode changes may be made under software control, or may be brought about by external interrupts or exception
processing. Most application programs execute in User mode. The non-user modes, or privileged modes, are entered in
order to service interrupts or exceptions, or to access protected resources.
11.2.4 ARM7TDMI Registers
The ARM7TDMI processor has a total of 37registers:
31 general-purpose 32-bit registers
6 status registers
These registers are not accessible at the same time . The processor state and operating mode determine which registers
are available to the programmer.
At any one time 16 registers are visible to the user. The remainder are synonyms used to speed up exception
processing.
Register 15 is the Program Counter (PC) and can be used in all instructions to reference data relative to the current
instruction.
R14 holds the return address after a subroutine call.
R13 is used (by software convention) as a stack pointer.
Registers R0 to R7 are unbanked registers. This means that each of them refers to the same 32-bit physical register in all
processor modes. They are general-purpose registers, with no special uses managed by the architecture, and can be
used wherever an instruction allows a general-purpose register to be specified.
Registers R8 to R14 are banked registers. This means that each of them depends on the current mode of the processor.
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11.2.4.1 Modes and Exception Handling
All exceptions have banked registers for R14 and R13.
After an exception, R14 holds the return address for exception processing. This address is used to return after the
exception is processed, as well as to address the instruction that caused the exception.
R13 is banked across exception modes to provide each exception handler with a private stack pointer.
The fast interrupt mode also banks registers 8 to 12 so that interrupt processing can begin without having to save these
registers.
A seventh processing mode, System Mode, does not have any banked registers. It uses the User Mode registers.
System Mode runs tasks that require a privileged processor mode and allows them to invoke all classes of exceptions.
11.2.4.2 Status Registers
All other processor states are held in status registers. The current operating processor status is in the Current Program
Status Register (CPSR). The CPSR holds:
four ALU flags (Negative, Zero, Carry, and Overflow)
two interrupt disable bits (one for each type of interrupt)
one bit to indicate ARM or Thumb execution
five bits to encode the current processor mode
All five exception modes also have a Saved Program Status Register (SPSR) that holds the CPSR of the task
immediately preceding the exception.
Table 11-1. ARM7TDMI ARM Modes and Registers Layout
User and
System Mode Supervisor
Mode Abort Mode Undefined
Mode Interrupt
Mode Fast Interrupt
Mode
R0 R0 R0 R0 R0 R0
R1 R1 R1 R1 R1 R1
R2 R2 R2 R2 R2 R2
R3 R3 R3 R3 R3 R3
R4 R4 R4 R4 R4 R4
R5 R5 R5 R5 R5 R5
R6 R6 R6 R6 R6 R6
R7 R7 R7 R7 R7 R7
R8 R8 R8 R8 R8 R8_FIQ
R9 R9 R9 R9 R9 R9_FIQ
R10 R10 R10 R10 R10 R10_FIQ
R11 R11 R11 R11 R11 R11_FIQ
R12 R12 R12 R12 R12 R12_FIQ
R13 R13_SVC R13_ABORT R13_UNDEF R13_IRQ R13_FIQ
R14 R14_SVC R14_ABORT R14_UNDEF R14_IRQ R14_FIQ
PC PC PC PC PC PC
CPSR CPSR CPSR CPSR CPSR CPSR
SPSR_SVC SPSR_ABORT SPSR_UNDEF SPSR_IRQ SPSR_FIQ
Mode-specific banked registers
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11.2.4.3 Exception Types
The ARM7TDMI supports five types of exception and a privileged processing mode for each type. The types of exceptions
are:
fast interrupt (FIQ)
normal interrupt (IRQ)
memory aborts (used to implement memory protection or virtual memory)
attempted execution of an undefined instruction
software interrupts (SWIs)
Exceptions are generated by internal and external sources.
More than one exception can occur in the same time.
When an exception occurs, the banked version of R14 and the SPSR for the exception mode are used to save state.
To return after handling the exception, the SPSR is moved to the CPSR, and R14 is moved to the PC. This can be done
in two ways:
by using a data-processing instruction with the S-bit set, and the PC as the destination
by using the Load Multiple with Restore CPSR instruction (LDM)
11.2.5 ARM Instruction Set Overview
The ARM instruction set is divided into:
Branch instructions
Data processing instructions
Status register transfer instructions
Load and Store instructions
Coprocessor instructions
Exception-generating instructions
ARM instructions can be executed conditionally. Every instruction contains a 4-bit condition code field (bit[31:28]).
Table 11-2 gives the ARM instruction mnemonic list.
Table 11-2. ARM Instruction Mnemonic List
Mnemonic Operation Mnemonic Operation
MOV Move CDP Coprocessor Data Processing
ADD Add MVN Move Not
SUB Subtract ADC Add with Carry
RSB Reverse Subtract SBC Subtract with Carry
CMP Compare RSC Reverse Subtract with Carry
TST Test CMN Compare Negated
AND Logical AND TEQ Test Equivalence
EOR Logical Exclusive OR BIC Bit Clear
MUL Multiply ORR Logical (inclusive) OR
SMULL Sign Long Multiply MLA Multiply Accumulate
SMLAL Signed Long Multiply Accumulate UMULL Unsigned Long Multiply
MSR Move to Status Register UMLAL Unsigned Long Multiply Accumulate
B Branch MRS Move From Status Register
BX Branch and Exchange BL Branch and Link
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11.2.6 Thumb Instruction Set Overview
The Thumb instruction set is a re-encoded subset of the ARM instruction set.
The Thumb instruction set is divided into:
Branch instructions
Data processing instructions
Load and Store instructions
Load and Store Multiple instructions
Exception-generating instruction
In Thumb mode, eight general-purpose registers, R0 to R7, are available that are the same physical registers as R0 to
R7 when executing ARM instructions. Some Thumb instructions also access to the Program Counter (ARM Register 15),
the Link Register (ARM Register 14) and the Stack Pointer (ARM Register 13). Further instructions allow limited access
to the ARM registers 8 to 15.
Table 11-3 gives the Thumb instruction mnemonic list.
LDR Load Word SWI Software Interrupt
LDRSH Load Signed Halfword STR Store Word
LDRSB Load Signed Byte STRH Store Half Word
LDRH Load Half Word STRB Store Byte
LDRB Load Byte STRBT Store Register Byte with Translation
LDRBT Load Register Byte with Translation STRT Store Register with Translation
LDRT Load Register with Translation STM Store Multiple
LDM Load Multiple SWPB Swap Byte
SWP Swap Word MRC Move From Coprocessor
MCR Move To Coprocessor STC Store From Coprocessor
LDC Load To Coprocessor
Table 11-2. ARM Instruction Mnemonic List
Mnemonic Operation Mnemonic Operation
Table 11-3. Thumb Instruction Mnemonic List
Mnemonic Operation Mnemonic Operation
MOV Move MVN Move Not
ADD Add ADC Add with Carry
SUB Subtract SBC Subtract with Carry
CMP C ompare CMN Compare Negated
TST Test NEG Negate
AND Logical AND BIC Bit Clear
EOR Logical Exclusive OR OR R Logical (inclusive) OR
LSL Logical Shift Left LSR Logical Shift Right
ASR Arithmetic Shift Right ROR Rotate Right
MUL Multiply
B Branch BL Branch and Link
BX Branch and Exchange SWI Software Interrupt
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LDR Load Word STR Store Word
LDRH Load Half Word STRH Store Half Word
LDRB Load Byte STRB Store Byte
LDRSH Load Signed Halfword LDRSB Load Signed Byte
LDMIA Load Multiple STMIA Store Multiple
PUSH Push Register to stack POP Pop Register from stack
Table 11-3. Thumb Instruction Mnemonic List
Mnemonic Operation Mnemonic Operation
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12. Debug and Test Features
12.1 Description
The SAM7X Series features a number of complementary debug and test capabilities. A common JTAG/ICE (In-Circuit
Emulator) port is used for standard debugging functions, such as downloading code and single-stepping through
programs. The Debug Unit provides a two-pin UART that can be used to upload an application into internal SRAM. It
manages the interrupt handling of the internal COMMTX and COMMRX signals that trace the activity of the Debug
Communication Channel.
A set of dedicated debug and test input/output pins gives direct access to these capabilities from a PC-based test
environment.
12.2 Block Diagram
Figure 12-1. Debug and Test Block Diagram
ICE
PDC DBGU
PIO
DRXD
DTXD
TST
TMS
TCK
TDI
JTAGSEL
TDO
Boundary
TAP
ICE/JTAG
TAP
ARM7TDMI
Reset
and
Test
POR
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12.3 Application Examples
12.3.1 Debug Environment
Figure 12-2 shows a complete debug environment example. The ICE/JTAG interface is used for standard debugging
functions, such as downloading code and single-stepping through the program.
Figure 12-2. Applicatio n Debug Environment Example
ICE/JTAG
Interface
Host Debugger
ICE/JTAG
Connector
Terminal
RS232
Connector
AT91SAMSxx
AT91SAM7Sxx-based Application Board
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12.3.2 Test Environment
Figure 12-3 shows a test environment example. Test vectors are sent and interpreted by the tester. In this example, the
“board in test” is designed using a number of JTAG-compliant devices. These devices can be connected to form a single
scan chain.
Figure 12-3. Application Test Environment Example
12.4 Debug and Test Pin Description
12.5 Functional Description
12.5.1 Test Pin
One dedicated pin, TST, is used to define the device operating mode. The user must make sure that this pin is tied at low
level to ensure normal operating conditions. Other values associated with this pin are reserved for manufacturing test.
Tester
JTAG
Interface
ICE/JTAG
Connector
AT91SAM7Xxx-based Application Board In Test
AT91SAM7Xxx
Test Adaptor
Chip 2Chip n
Chip 1
Table 12-1 . Debug and Tes t Pin List
Pin Name Function Type Active Leve l
Reset/Test
NRST Microcontroller Reset Input/Output Low
TST Test Mode Select Input High
ICE and JTAG
TCK Test Clock Input
TDI Test Data In Input
TDO Test Data Out Output
TMS Test Mode Select Input
JTAGSEL JTAG Selection Input
Debug Unit
DRXD Debug Receive Data Input
DTXD Debug Transmit Data Output
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12.5.2 EmbeddedICE (Embedded In-circuit Emulator)
The ARM7TDMI EmbeddedICE is supported via the ICE/JTAG port. The internal state of the ARM7TDMI is examined
through an ICE/JTAG port.
The ARM7TDMI processor contains hardware extensions for advanced debugging features:
In halt mode, a store-multiple (STM) can be inserted into the instruction pipeline. This exports the contents of the
ARM7TDMI registers. This data can be serially shifted out without affecting the rest of the system.
In monitor mode, the JTAG interface is used to transfer data between the debugger and a simple monitor program
running on the ARM7TDMI processor.
There are three scan chains inside the ARM7TDMI processor that support testing, debugging, and programming of the
EmbeddedICE. The scan chains are controlled by the ICE/JTAG port.
EmbeddedICE mode is selected when JTAGSEL is low. It is not possible to switch directly between ICE and JTAG
operations. A chip reset must be performed after JTAGSEL is changed.
For further details on the EmbeddedICE, see the ARM7TDMI (Rev4) Technical Reference Manual (DDI0210B).
12.5.3 Debug Unit
The Debug Unit provides a two-pin (DXRD and TXRD) USART that can be used for several debug and trace purposes
and offers an ideal means for in-situ programming solutions and debug monitor communication. Moreover, the
association with two peripheral data controller channels permits packet handling of these tasks with processor time
reduced to a minimum.
The Debug Unit also manages the interrupt handling of the COMMTX and COMMRX signals that come from the ICE and
that trace the activity of the Debug Communication Channel. The Debug Unit allows blockage of access to the system
through the ICE interface.
A specific register, the Debug Unit Chip ID Register, gives information about the product version and its internal
configuration.
The SAM7X512 Debug Unit Chip ID value is 0x275C 0A40 on 32-bit width.
The SAM7X256 Debug Unit Chip ID value is 0x275B 0940 on 32-bit width.
The SAM7X128 Debug Unit Chip ID value is 0x275A 0740 on 32-bit width.
For further details on the Debug Unit, see the Debug Unit section.
12.5.4 IEEE 1149.1 JTAG Boundary Scan
IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging technology.
IEEE 1149.1 JTAG Boundary Scan is enabled when JTAGSEL is high. The SAMPLE, EXTEST and BYPASS functions
are implemented. In ICE debug mode, the ARM processor responds with a non-JTAG chip ID that identifies the
processor to the ICE system. This is not IEEE 1149.1 JTAG-compliant.
It is not possible to switch directly between JTAG and ICE operations. A chip reset must be performed after JTAGSEL is
changed.
A Boundary-scan Descriptor Language (BSDL) file is provided to set up test.
12.5.4.1 JTAG Boundary-scan Register
The Boundary-scan Register (BSR) contains 187 bits that correspond to active pins and associated control signals.
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Each SAM7X input/output pin corresponds to a 3-bit register in the BSR. The OUTPUT bit contains data that can be
forced on the pad. The INPUT bit facilitates the observability of data applied to the pad. The CONTROL bit selects the
direction of the pad.
Table 12-2. SAM7X JTAG Boundar y Scan Re gister
Bit
Number Pin Name Pi n Type Associated BSR
Cells
187
PA30/IRQ0/PCK2 IN/OUT
INPUT
186 OUTPUT
185 CONTROL
184
PA0/RXD0 IN/OUT
INPUT
183 OUTPUT
182 CONTROL
181
PA1/TXD0 IN/OUT
INPUT
180 OUTPUT
179 CONTROL
178
PA3/RTS0/SPI1_NPCS2 IN/OUT
INPUT
177 OUTPUT
176 CONTROL
175
PA2/SCK0/SPI1_NPCS1 IN/OUT
INPUT
174 OUTPUT
173 CONTROL
172
PA4/CTS0/SPI1_NPCS3 IN/OUT
INPUT
171 OUTPUT
170 CONTROL
169
PA5/RXD1 IN/OUT
INPUT
168 OUTPUT
167 CONTROL
166
PA6/TXD1 IN/OUT
CONTROL
165 INPUT
164 OUTPUT
163
PA7/SCK1/SPI0_NPCS1 IN/OUT
CONTROL
162 INPUT
161 OUTPUT
160 ERASE IN INPUT
159
PB27/TIOA2/PWM0/AD0 IN/OUT
INPUT
158 OUTPUT
157 CONTROL
156
PB28/TIOB2/PWM1/AD1 IN/OUT
INPUT
155 OUTPUT
154 CONTROL
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153
PB29/PCK1/PWM2/AD2 IN/OUT
INPUT
152 OUTPUT
151 CONTROL
150
PB30/PCK2/PWM3/AD3 IN/OUT
INPUT
149 OUTPUT
148 CONTROL
147
PA8/RTS1/SPI0_NPCS2 IN/OUT
INPUT
146 OUTPUT
145 CONTROL
144
PA9/CTS1/SPI0_NPCS3 IN/OUT
INPUT
143 OUTPUT
142 CONTROL
141
PA10/TWD IN/OUT
INPUT
140 OUTPUT
139 CONTROL
138
PA11/TWCK IN/OUT
INPUT
137 OUTPUT
136 CONTROL
135
PA12/SPI0_NPCS0 IN/OUT
INPUT
134 OUTPUT
133 CONTROL
132
PA13/SPI0_NPCS1/PCK1 IN/OUT
INPUT
131 OUTPUT
130 CONTROL
129
PA14/SPI0_NPCS2/IRQ1 IN/OUT
INPUT
128 OUTPUT
127 CONTROL
126
PA15/SPI0_NPCS3/TCLK2 IN/OUT
INPUT
125 OUTPUT
124 CONTROL
123
PA16/SPI0_MISO IN/OUT
INPUT
122 OUTPUT
121 CONTROL
120
PA17/SPI0_MOSI IN/OUT
INPUT
119 OUTPUT
118 CONTROL
Table 12-2. SAM7X JTAG Boundar y Scan Re gister (Continued)
Bit
Number Pin Name Pi n Type Associated BSR
Cells
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117
PA18/SPI0_SPCK IN/OUT
INPUT
116 OUTPUT
115 CONTROL
114
PB9/EMDIO IN/OUT
INPUT
113 OUTPUT
112 CONTROL
111
PB8/EMDC IN/OUT
INPUT
110 OUTPUT
109 CONTROL
108
PB14/ERX3/SPI0_NPCS2 IN/OUT
INPUT
107 OUTPUT
106 CONTROL
105
PB13/ERX2/SPI0_NPCS1 IN/OUT
INPUT
104 OUTPUT
103 CONTROL
102
PB6/ERX1 IN/OUT
INPUT
101 OUTPUT
100 CONTROL
99
PB5/ERX0 IN/OUT
INPUT
98 OUTPUT
97 CONTROL
96
PB15/ERXDV/ECRSDV IN/OUT
INPUT
95 OUTPUT
94 CONTROL
93
PB17/ERXCK/SPI0_NPCS3 IN/OUT
INPUT
92 OUTPUT
91 CONTROL
90
PB7/ERXER IN/OUT
INPUT
89 OUTPUT
88 CONTROL
87
PB12/ETXER/TCLK0 IN/OUT
INPUT
86 OUTPUT
85 CONTROL
84
PB0/ETXCK/EREFCK/PCK0 PB0/ETXCK/ERE
FCK/PCK0
INPUT
83 OUTPUT
82 CONTROL
Table 12-2. SAM7X JTAG Boundar y Scan Re gister (Continued)
Bit
Number Pin Name Pi n Type Associated BSR
Cells
51
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
81
PB1/ETXEN PB1/ETXEN
INPUT
80 OUTPUT
79 CONTROL
78
PB2/ETX0 PB2/ETX0
INPUT
77 OUTPUT
76 CONTROL
75
PB3/ETX1 PB3/ETX1
INPUT
74 OUTPUT
73 CONTROL
72
PB10/ETX2/SPI1_NPCS1 IN/OUT
INPUT
71 OUTPUT
70 CONTROL
69
PB11/ETX3/SPI1_NPCS2 IN/OUT
INPUT
68 OUTPUT
67 CONTROL
66
PA19/CANRX IN/OUT
INPUT
65 OUTPUT
64 CONTROL
63
PA20/CANTX IN/OUT
INPUT
62 OUTPUT
61 CONTROL
60
PA21/TF/SPI1_NPCS0 IN/OUT
INPUT
59 OUTPUT
58 CONTROL
57
PA22/TK/SPI1_SPCK IN/OUT
INPUT
56 OUTPUT
55 CONTROL
54
PB16/ECOL/SPI1_NPCS3 IN/OUT
INPUT
53 OUTPUT
52 CONTROL
51
PB4/ECRS IN/OUT
INPUT
50 OUTPUT
49 CONTROL
48
PA23/TD/SPI1_MOSI IN/OUT
INPUT
47 OUTPUT
46 CONTROL
Table 12-2. SAM7X JTAG Boundar y Scan Re gister (Continued)
Bit
Number Pin Name Pi n Type Associated BSR
Cells
52
SAM7X Series [DATASHEET]
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45
PA24/RD/SPI1_MISO IN/OUT
INPUT
44 OUTPUT
43 CONTROL
42
PA25/RK/SPI1_NPCS1 IN/OUT
INPUT
41 OUTPUT
40 CONTROL
39
PA26/RF/SPI1_NPCS2 IN/OUT
INPUT
38 OUTPUT
37 CONTROL
36
PB18/EF100/ADTRG IN/OUT
INPUT
35 OUTPUT
34 CONTROL
33
PB19/PWM0/TCLK1 IN/OUT
INPUT
32 OUTPUT
31 CONTROL
30
PB20/PWM1/PCK0 IN/OUT
INPUT
29 OUTPUT
28 CONTROL
27
PB21/PWM2/PCK2 IN/OUT
INPUT
26 OUTPUT
25 CONTROL
24
PB22/PWM3/PCK2 IN/OUT
INPUT
23 OUTPUT
22 CONTROL
21
PB23/TIOA0/DCD1 IN/OUT
INPUT
20 OUTPUT
19 CONTROL
18
PB24/TIOB0/DSR1 IN/OUT
INPUT
17 OUTPUT
16 CONTROL
15
PB25/TIOA1/DTR1 IN/OUT
INPUT
14 OUTPUT
13 CONTROL
12
PB26/TIOB1/RI1 IN/OUT
INPUT
11 OUTPUT
10 CONTROL
Table 12-2. SAM7X JTAG Boundar y Scan Re gister (Continued)
Bit
Number Pin Name Pi n Type Associated BSR
Cells
53
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
9
PA27DRXD/PCK3 IN/OUT
INPUT
8OUTPUT
7CONTROL
6
PA28/DTXD IN/OUT
INPUT
5OUTPUT
4CONTROL
3
PA29/FIQ/SPI1_NPCS3 IN/OUT
INPUT
2OUTPUT
1CONTROL
Table 12-2. SAM7X JTAG Boundar y Scan Re gister (Continued)
Bit
Number Pin Name Pin Type Associated BSR
Cells
54
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
12.5.5 ID Code Register
Access: Read-only
• VERSION[31:28]: Product Version Number
Set to 0x0.
• PART NUMBER[27:12]: Product Part Number
AT91SAM7X512: 0x5B18
AT91SAM7X256: 0x5B17
AT91SAM7X128: 0x5B16
• MANUFAC TURER IDENTITY[11:1]
Set to 0x01F.
Bit[0] Required by IEEE Std. 1149.1.
Set to 0x1.
AT91SAM7X512: JTAG ID Code value is 05B1_803F
AT91SAM7X256: JTAG ID Code value is 05B1_703F
AT91SAM7X128: JTAG ID Code value is 05B1_603F
31 30 29 28 27 26 25 24
VERSION PART NUMBER
23 22 21 20 19 18 17 16
PART NUMBER
15 14 13 12 11 10 9 8
PART NUMBER MANUFACTURER IDENTITY
76543210
MANUFACTURER IDENTITY 1
55
SAM7X Series [DATASHEET]
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13. Reset Controller (RSTC)
The Reset Controller (RSTC), based on power-on reset cells, handles all the resets of the system without any external
components. It reports which reset occurred last.
The Reset Controller also drives independently or simultaneously the external reset and the peripheral and processor
resets.
A brownout detection is also available to prevent the processor from falling into an unpredictable state.
13.1 Block Diagram
Figure 13-1. Reset Controller Block Diagram
NRST
Startup
Counter
proc_nreset
wd_fault
periph_nreset
SLCK
Reset
State
Manager
Reset Controller
brown_out
bod_rst_en
rstc_irq
NRST
Manager exter_nreset
nrst_out
Main Supply
POR
WDRPROC
user_reset
Brownout
Manager bod_reset
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13.2 Functional Description
13.2.1 Reset Controller Overview
The Reset Controller is made up of an NRST Manager, a Brownout Manager, a Startup Counter and a Reset State
Manager. It runs at Slow Clock and generates the following reset signals:
proc_nreset: Processor reset line. It also resets the Watchdog Timer.
periph_nreset: Affects the whole set of embedded peripherals.
nrst_out: Drives the NRST pin.
These reset signals are asserted by the Reset Controller, either on external events or on software action. The Reset
State Manager controls the generation of reset signals and provides a signal to the NRST Manager when an assertion of
the NRST pin is required.
The NRST Manager shapes the NRST assertion during a programmable time, thus controlling external device resets.
The startup counter waits for the complete crystal oscillator startup. The wait delay is given by the crystal oscillator
startup time maximum value that can be found in the section Crystal Oscillator Characteristics in the Electrical
Characteristics section of the product documentation.
13.2.2 NRST Manager
The NRST Manager samples the NRST input pin and drives this pin low when required by the Reset State Manager.
Figure 13-2 shows the block diagram of the NRST Manager.
Figure 13-2. NRST Manager
13.2.2.1 NRST Signal or Interrupt
The NRST Manager samples the NRST pin at Slow Clock speed. When the line is detected low, a User Reset is reported
to the Reset State Manager.
However, the NRST Manager can be programmed to not trigger a reset when an assertion of NRST occurs. Writing the
bit URSTEN at 0 in RSTC_MR disables the User Reset trigger.
The level of the pin NRST can be read at any time in the bit NRSTL (NRST level) in RSTC_SR. As soon as t he pin NRST
is asserted, the bit URSTS in RSTC_SR is set. This bit clears only when RSTC_SR is read.
The Reset Controller can also be programmed to generate an interrupt instead of generating a reset. To do so, the bit
URSTIEN in RSTC_MR must be written at 1.
13.2.2.2 NRST External Reset Control
The Reset State Manager asserts the signal ext_nreset to assert the NRST pin. When this occurs, the “nrst_out ” signal is
driven low by the NRST Manager for a time programmed by the field ERSTL in RSTC_MR. This assertion duration,
named EXTERNAL_RESET_LENGTH, lasts 2(ERSTL+1) Slow Clock cycles. This gives the approximate duration of an
assertion between 60 µs and 2 seconds. Note that ERSTL at 0 defines a two-cycle duration for the NRST pulse.
External Reset Timer
URSTS
URSTEN
ERSTL
exter_nreset
URSTIEN
RSTC_MR
RSTC_MR
RSTC_MR
RSTC_SR
NRSTL
nrst_out
NRST
rstc_irq
Other
interrupt
sources
user_reset
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This feature allows the Reset Controller to shape the NRST pin level, and thus to guarantee that the NRST line is driven
low for a time compliant with potential external devices connected on the system reset.
13.2.3 Brownout Manager
Brownout detection prevents the processor from falling into an unpredictable state if the power supply drops below a
certain level. When VDDCORE drops below the brownout threshold, the brownout manager requests a brownout reset
by asserting the bod_reset signal.
The programmer can disable the brownout reset by setting low the bod_rst_en input signal, i.e.; by locking the
corresponding general-purpose NVM bit in the Flash. When the brownout reset is disabled, no reset is performed.
Instead, the brownout detection is reported in the bit BODSTS of RSTC_SR. BODSTS is set and clears only when
RSTC_SR is read.
The bit BODSTS can trigger an interrupt if the bit BODIEN is set in the RSTC_MR.
At factory, the brownout reset is disabled.
Figure 13-3. Brownout Manager
rstc_irq
brown_out
bod_reset
bod_rst_en
BODIEN
RSTC_MR
BODSTS
RSTC_SR
Other
interrupt
sources
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13.2.4 Reset States
The Reset State Manager handles the different reset sources and generates the internal reset signals. It reports the reset
status in the field RSTTYP of the Status Register (RSTC_SR). The update of the field RSTTYP is performed when the
processor reset is released.
13.2.4.1 Power-up Reset
When VDDCORE is powered on, the Main Supply POR cell output is filtered with a start-up counter that operates at Slow
Clock. The purpose of this counter is to ensure that the Slow Clock oscillator is stable before starting up the device.
The startup time, as shown in Figure 13-4, is hardcoded to comply with the Slow Clock Oscillator startup time. After the
startup time, the reset signals are released and the field RSTTYP in RSTC_SR reports a Power-up Reset.
When VDDCORE is detected low by the Main Supply POR Cell, all reset signals are asserted immediately.
Figure 13-4. Power-up Reset
SLCK
periph_nreset
proc_nreset
Main Supply
POR output
NRST
(nrst_out)
EXTERNAL RESET LENGTH
= 2 cycles
Startup Time
MCK
Processor Startup
= 3 cycles
Any
Freq.
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13.2.4.2 User Reset
The User Reset is entered when a low level is detected on the NRST pin and the bit URSTEN in RSTC_MR is at 1. The
NRST input signal is resynchronized with SLCK to insure proper behavior of the system.
The User Reset is entered as soon as a low level is detected on NRST. The Processor Reset and the Peripheral Reset
are asserted.
The User Reset is left when NRST rises, after a two-cycle resynchronization time and a three-cycle processor startup.
The processor clock is re-enabled as soon as NRST is confirmed high.
When the processor reset signal is released, the RSTTYP field of the Status Register (RSTC_SR) is loaded with the
value 0x4, indicating a User Reset.
The NRST Manager guarantees that the NRST line is asserted for EXTERNAL_RESET_LENGTH Slow Clock cycles, as
programmed in the field ERSTL. However, if NRST does not rise after EXTERNAL_RESET_LENGTH because it is
driven low externally, the internal reset lines remain asserted until NRST actually rises.
Figure 13-5. User Reset State
SLCK
periph_nreset
proc_nreset
NRST
NRST
(nrst_out)
>= EXTERNAL RESET LENGTH
MCK
Processor Startup
= 3 cycles
Any
Freq.
Resynch.
2 cycles
RSTTYP Any XXX
Resynch.
2 cycles
0x4 = User Reset
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13.2.4.3 Brownout Reset
When the brown_out/bod_reset signal is asserted, the Reset State Manager immediately enters the Brownout Reset. In
this state, the processor, the peripheral and the external reset lines are asserted.
The Brownout Reset is left 3 Slow Clock cycles after the rising edge of brown_out/bod_reset after a two-cycle
resynchronization. An external reset is also triggered.
When the processor reset is released, the field RSTTYP in RSTC_SR is loaded with the value 0x5, thus indicating that
the last reset is a Brownout Reset.
Figure 13-6. Brownout Reset State
SLCK
periph_nreset
proc_nreset
brown_out
or bod_reset
NRST
(nrst_out)
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
MCK
Processor Startup
= 3 cycles
Any
Freq.
RSTTYP Any XXX 0x5 = Brownout Reset
Resynch.
2 cycles
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13.2.4.4 Software Reset
The Reset Controller offers several commands used to assert the different reset signals. These commands are
performed by writing the Control Register (RSTC_CR) with the following bits at 1:
PROCRST: Writing PROCRST at 1 resets the processor and the watchdog timer.
PERRST: Writing PERRST at 1 resets all the embedded peripherals, including the memory system, and, in
particular, the Remap Command. The Peripheral Reset is generally used for debug purposes.
Except for Debug purposes, PERRST must always be used in conjuction with PROCRST (PERRST and
PROCRST set both at 1 simultaneously).
EXTRST: Writing EXTRST at 1 asserts low the NRST pin during a time defined by the field ERSTL in the Mode
Register (RSTC_MR).
The software reset is entered if at least one of these bits is set by the software. All these commands can be performed
independently or simultaneously. The software reset lasts 3 Slow Clock cycles.
The internal reset signals are asserted as soon as the register write is performed. This is detected on the Master Clock
(MCK). They are released when the software reset is left, i.e.; synchronously to SLCK.
If EXTRST is set, the nrst_out signal is asserted depending on the programming of the field ERSTL. However, the
resulting falling edge on NRST does not lead to a User Reset.
If and only if the PROCRST bit is set, the Reset Controller reports the software status in the field RSTTYP of the Status
Register (RSTC_SR). Other Software Resets are not reported in RSTTYP.
As soon as a software operation is detected, the bit SRCMP (Software Reset Command in Progress) is set in the Status
Register (RSTC_SR). It is cleared as soon as the software reset is left. No other software reset can be performed while
the SRCMP bit is set, and writing any value in RSTC_CR has no effect.
Figure 13-7. Software Reset
SLCK
periph_nreset
if PERRST=1
proc_nreset
if PROCRST=1
Write RSTC_CR
NRST
(nrst_out)
if EXTRST=1 EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
MCK
Processor Startup
= 3 cycles
Any
Freq.
RSTTYP Any XXX 0x3 = Software Reset
Resynch.
1 cycle
SRCMP in RSTC_SR
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13.2.4.5 Watchdog Reset
The Watchdog Reset is entered when a watchdog fault occurs. This state lasts 3 Slow Clock cycles.
When in Watchdog Reset, assertion of the reset signals depends on the WDRPROC bit in WDT_MR:
If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST line is also asserted,
depending on the programming of the field ERSTL. However, the resulting low level on NRST does not result in a
User Reset state.
If WDRPROC = 1, only the processor reset is asserted.
The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a processor reset if
WDRSTEN is set, the Watchdog Timer is always reset after a Watchdo g Re set , and the Watchdog is enabled by d efault
and with a period set to a maximum.
When the WDRSTEN in WDT_MR bit is reset, the watchdog fault has no impact on the reset controller.
Figure 13-8. Watchdog Reset
Only if
WDRPROC = 0
SLCK
periph_nreset
proc_nreset
wd_fault
NRST
(nrst_out)
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
MCK
Processor Startup
= 3 cycles
Any
Freq.
RSTTYP Any XXX 0x2 = Watchdog Reset
63
SAM7X Series [DATASHEET]
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13.2.5 Reset State Priorities
The Reset State Manager manages the following priorities between the different reset sources, given in descending
order:
Power-up Reset
Brownout Reset
Watchdog Res et
Software Reset
User Reset
Particular cases are listed below:
When in User Reset:
A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal.
A software reset is impossible, since the processor reset is being activated.
When in Software Reset:
A watchdog event has priority over the current state.
The NRST has no effect.
When in Watchdog Reset:
The processor reset is active and so a Software Reset cannot be programmed.
A User Reset cannot be entered.
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13.2.6 Reset Controller Status Register
The Reset Controller status register (RSTC_SR) provides several status fields:
RSTTYP field: This field gives the type of the last reset, as explained in previous sections.
SRCMP bit: This field indicates that a Software Reset Command is in progress and that no further software reset
should be performed until the end of the current one. This bit is automatically cleared at the end of the current
software reset.
NRSTL bit: The NRSTL bit of the Status Register gives the level of the NRST pin sampled on each MCK rising
edge.
URSTS bit: A high-to-low transition of the NRST pin sets the URSTS bit of the RSTC_SR register. This transition is
also detected on the Master Clock (MCK) rising edge (see Figure 13-9). If the User Reset is disabled (URSTEN =
0) and if the interruption is enabled by the URSTIEN bit in the RSTC_MR register, the URSTS bit triggers an
interrupt. Reading the RSTC_SR status register resets the URSTS bit and clears the interrupt.
BODSTS bit: This bit indicates a brownout detection when the brownout reset is disabled (bod_rst_en = 0). It
triggers an interrupt if the bit BODIEN in the RSTC_MR register enables the interrupt. Reading the RSTC_SR
register resets the BODSTS bit and clears the interrupt.
Figure 13-9. Reset Controller Status and Interrupt
MCK
NRST
NRSTL
2 cycle
resynchronization 2 cycle
resynchronization
URSTS
read
RSTC_SR
Peripheral Access
rstc_irq
if (URSTEN = 0) and
(URSTIEN = 1)
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13.3 Reset Controller (RSTC) User Interface
Table 13-1. Regist er Mapping
Offset Register Name Access Reset
0x00 Control Register RSTC_CR Write-only -
0x04 Status Register RSTC_SR Read-only 0x000 0_0000
0x08 Mode Register RSTC_MR Read-write 0x0000_0000
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SAM7X Series [DATASHEET]
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13.3.1 Reset Controller Control Register
Register Name: RSTC_CR
Access Type: Write-only
• PROCRST: Processor Reset
0 = No effect.
1 = If KEY is correct, resets the processor.
• PERRST: Peripheral Reset
0 = No effect.
1 = If KEY is correct, resets the peripherals.
• EXTRST: External Reset
0 = No effect.
1 = If KEY is correct, asserts the NRST pin.
•KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– –
76543210
––––EXTRSTPERRST–PROCRST
67
SAM7X Series [DATASHEET]
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13.3.2 Reset Controller Status Register
Register Name: RSTC_SR
Access Type: Read-only
• URSTS: User Reset Status
0 = No high-to-low edge on NRST happened since the last read of RSTC_SR.
1 = At least one high-to-low transition of NRST has been detected since the last read of RSTC_SR.
• BODSTS: Brownout Detection Status
0 = No brownout high-to-low transition happened since the last read of RSTC_SR.
1 = A brownout high-to-low transition has been detected since the last read of RSTC_SR.
• RSTTYP: Reset Type
Reports the cause of the last processor reset. Reading this RSTC_SR does not reset this field.
• NRSTL: NRST Pin Level
Registers the NRST Pin Level at Master Clock (MCK).
• SRCMP: Software Reset Command in Progress
0 = No software command is being performed by the reset controller. The reset controller is ready for a software command.
1 = A software reset command is being performed by the reset controller. The reset controller is busy.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––SRCMPNRSTL
15 14 13 12 11 10 9 8
––––– RSTTYP
76543210
––––––BODSTSURSTS
RSTTYP Reset Type Comments
0 0 0 Power-up Reset VDDCORE rising
0 1 0 Watch dog Reset Watchdog fault occurred
0 1 1 Sof tware Reset Processor reset required by the software
1 0 0 User Reset NRST pin detected low
1 0 1 Brownout Reset Brownout reset occurred
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SAM7X Series [DATASHEET]
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13.3.3 Reset Controller Mode Register
Register Name: RSTC_MR
Access Type: Read-write
• URSTEN: User Reset Enable
0 = The detection of a low level on the pin NRST does not generate a User Reset.
1 = The detection of a low level on the pin NRST triggers a User Reset.
• URSTIEN: User Reset Interrupt Enable
0 = USRTS bit in RSTC_SR at 1 has no effect on rstc_irq.
1 = USRTS bit in RSTC_SR at 1 asserts rstc_irq if URSTEN = 0.
• BODIEN: Brownout Detection Interrupt Enable
0 = BODSTS bit in RSTC_SR at 1 has no effect on rstc_irq.
1 = BODSTS bit in RSTC_SR at 1 asserts rstc_irq.
• ERSTL: External Reset Length
This field defines the external reset length. The external reset is asserted during a time of 2(ERSTL+1) Slow Clock cycles. This
allows assertion duration to be programmed between 60 µs and 2 seconds.
•KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
–––––––BODIEN
15 14 13 12 11 10 9 8
–––– ERSTL
76543210
– – URSTIEN – – – URSTEN
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SAM7X Series [DATASHEET]
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14. Real-time Timer (RTT)
14.1 Overview
The Real-time Timer is built around a 32-bit counter and used to count elapsed seconds. It generates a periodic interrupt
or/and triggers an alarm on a programmed value.
14.2 Block Diagram
Figure 14-1. Real-time Timer
14.3 Functional Description
The Real-time Timer is used to count elapsed seconds. It is built around a 32-bit counter fed by Slow Clock divided by a
programmable 16-bit value. The value can be programmed in the field RTPRES of the Real-time Mode Register
(RTT_MR).
Programming RTPRES at 0x00008000 corresponds to feeding the real-time counter with a 1 Hz signal (if the Slow Clock
is 32.768 Hz). The 32-bit counter can count up to 232 seconds, corresponding to more than 136 years, then roll over to 0.
The Real-time Timer can also be used as a free-running timer with a lower time-base. The best accuracy is achieved by
writing RTPRES to 3. Programming RTPRES to 1 or 2 is possible, but may result in losing status events because the
status register is cleared two Slow Clock cycles after read. Thus if the RTT is configured to trigger an interrupt, the
interrupt occurs during 2 Slow Clock cycles after reading RTT_SR. To prevent several executions of the interrupt
handler, the interrupt must be disabled in the interrupt handler and re-enabled when the status register is clear.
The Real-time Timer value (CRTV) can be read at any time in the register RTT_VR (Real-time Value Register). As this
value can be updated asynchronously from the Master Clock, it is advisable to read this register twice at the same value
to improve accuracy of the returned value.
SLCK
RTPRES
RTTINC
ALMS
16-bit
Divider
32-bit
Counter
ALMV =
CRTV
RTT_MR
RTT_VR
RTT_AR
RTT_SR
RTTINCIEN
RTT_MR
0
10
ALMIEN
rtt_int
RTT_MR
set
set
RTT_SR
read
RTT_SR
reset
reset
RTT_MR
reload
rtt_alarm
RTTRST
RTT_MR
RTTRST
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
The current value of the counter is compared with the value written in the alarm register RTT_AR (Real-time Alarm
Register). If the counter value matches the alarm, the bit ALMS in RTT_SR is set. The alarm register is set to its
maximum value, corresponding to 0xFFFF_FFFF, after a reset.
The bit RTTINC in RTT_SR is set each time the Real-time Timer counter is incremented. This bit can be used to start a
periodic interrupt, the period being one second when the RTPRES is programmed with 0x8000 and Slow Clock equal to
32.768 Hz.
Reading the RTT_SR status register resets the RTTINC and ALMS fields.
Writing the bit RTTRST in RTT_MR immediately reloads and restarts the clock divider with the new programmed value.
This also resets the 32-bit counter.
Note: Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK):
1) The restart of the counter and the reset of the RTT_VR current value register is effective only 2 slow clock
cycles after the write of the RTTRST bit in the RTT_MR register.
2) The status register flags reset is taken into account only 2 slow clock cycles after the read of the RTT_SR
(Status Register).
Figure 14-2. RTT Counting
Prescaler
ALMVALMV-10 ALMV+1
0
RTPRES - 1
RTT
APB cycle
read RTT_SR
ALMS (RTT_SR)
APB Interface
MCK
RTTINC (RTT_SR)
ALMV+2 ALMV+3
...
APB cycle
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SAM7X Series [DATASHEET]
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14.4 Real-time Ti mer (RTT) User Interface
Table 14-1. Register Mapping
Offset Register Name Access Reset Value
0x00 Mode Register RTT_MR Read-write 0x0000_8000
0x04 Alarm Register RTT_AR Read-write 0xFFFF_FFFF
0x08 Value Register RTT_VR Read-only 0x0000_0000
0x0C Status Register RTT_SR Read-only 0x0000_0000
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14.4.1 Real-time Timer Mode Register
Register Name: RTT_MR
Access Type: Read-write
• RTPRES: Real-time Timer Prescaler Value
Defines the number of SLCK periods required to increment the real-time timer. RTPRES is defined as follows:
RTPRES = 0: The Prescaler Period is equal to 216
RTPRES ≠ 0: The Prescaler Period is equal to RTPRES.
• ALMIEN: Alarm Interrupt Enable
0 = The bit ALMS in RTT_SR has no effect on interrupt.
1 = The bit ALMS in RTT_SR asserts interrupt.
• RTTINCIEN: Real-time Timer Increment Interrupt Enable
0 = The bit RTTINC in RTT_SR has no effect on interrupt.
1 = The bit RTTINC in RTT_SR asserts interrupt.
• RTTRST: Real -ti me T ime r Re st art
1 = Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––RTTRSTRTTINCIENALMIEN
15 14 13 12 11 10 9 8
RTPRES
76543210
RTPRES
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14.4.2 Real-time Timer Alarm Register
Register Name: RTT_AR
Access Type: Read-write
• ALMV: Alarm Value
Defines the alarm value (ALMV+1) compared with the Real-time Timer.
14.4.3 Real-time Timer Value Register
Register Name: RTT_VR
Access Type: Read-only
• CRTV: Current Real-time Value
Returns the current value of the Real-time Timer.
31 30 29 28 27 26 25 24
ALMV
23 22 21 20 19 18 17 16
ALMV
15 14 13 12 11 10 9 8
ALMV
76543210
ALMV
31 30 29 28 27 26 25 24
CRTV
23 22 21 20 19 18 17 16
CRTV
15 14 13 12 11 10 9 8
CRTV
76543210
CRTV
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14.4.4 Real-time Timer Status Register
Register Name: RTT_SR
Access Type: Read-only
• ALMS: Real-time Ala rm Statu s
0 = The Real-time Alarm has not occurred since the last read of RTT_SR.
1 = The Real-time Alarm occurred since the last read of RTT_SR.
• RTTINC: Real-time Timer Increment
0 = The Real-time Timer has not been incremented since the last read of the RTT_SR.
1 = The Real-time Timer has been incremented since the last read of the RTT_SR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––RTTINCALMS
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15. Periodic Interval Timer (PIT)
15.1 Overview
The Periodic Interval Timer (PIT) provides the operating system’s scheduler interrupt. It is designed to offer maximum
accuracy and efficient management, even for systems with long response time.
15.2 Block Diagram
Figure 15-1. Periodic Interval Timer
20-bit
Counter
MCK/16
PIV
PIT_MR
CPIV PIT_PIVR PICNT
12-bit
Adder
0
0
read PIT_PIVR
CPIV PICNT
PIT_PIIR
PITS
PIT_SR
set
reset
PITIEN
PIT_MR
pit_irq
1
0
10
MCK
Prescaler
= ?
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15.3 Functional Description
The Periodic Interval Timer aims at providing periodic interrupts for use by operating systems.
The PIT provides a programmable overflow counter and a reset-on-read feature. It is built around two counters: a 20-bit
CPIV counter and a 12-bit PICNT counter. Both counters work at Master Clock /16.
The first 20-bit CPIV counter increments from 0 up to a programmable overflow value set in the field PIV of the Mode
Register (PIT_MR). When the counter CPIV reaches this value, it resets to 0 and increments the Periodic Interval
Counter, PICNT. The status bit PITS in the Status Register (PIT_SR) rises and triggers an interrupt, provided the
interrupt is enabled (PITIEN in PIT_MR).
Writing a new PIV value in PIT_MR does not reset/restart the counters.
When CPIV and PICNT values are obtained by reading the Periodic Interval Value Register (PIT_PIVR), the overflow
counter (PICNT) is reset and the PITS is cleared, thus acknowledging the interrupt. The value of PICNT gives the
number of periodic intervals elapsed since the last read of PIT_PIVR.
When CPIV and PICNT values are obtained by reading the Periodic Interval Image Register (PIT_PIIR), there is no effect
on the counters CPIV and PICNT, nor on the bit PITS. For example, a profiler can read PIT_PIIR without clearing any
pending interrupt, whereas a timer interrupt clears the interrupt by reading PIT_PIVR.
The PIT may be enabled/disabled using the PITEN bit in the PIT_MR register (disabled on reset). The PITEN bit only
becomes effective when the CPIV value is 0. Figure 15-2 illustrates the PIT counting. After the PIT Enable bit is reset
(PITEN= 0), the CPIV goes on counting until the PIV value is reached, and is then reset. PIT restarts counting, only if the
PITEN is set again.
The PIT is stopped when the core enters debug state.
Figure 15-2. Enablin g/Disabling PIT with PITEN
MCK Prescaler
PIVPIV - 10
PITEN
10
0
15
CPIV 1
restarts MCK Prescaler
01
APB cycle
read PIT_PIVR
0
PICNT
PITS (PIT_SR)
MCK
APB Interface
APB cycle
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15.4 Periodic Interval Timer (PIT) User Interface
Table 15-1. Regist er Mapping
Offset Register Name Access Reset
0x00 Mode Register PIT_MR Read-write 0x000F_FFFF
0x04 Status Register PIT_SR Read-only 0x0000_0000
0x08 Periodic Interval Value Register PIT_PIVR Read-only 0x0000_000 0
0x0C Periodic In terval Image Register PIT_PIIR Read-only 0x0000_000 0
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15.4.1 Periodic Interval Timer Mode Register
Register Name: PIT_MR
Access Type: Read-write
• PIV: Pe riodic Interval Value
Defines the value compared with the primary 20-bit counter of the Periodic Interval Timer (CPIV). The period is equal to (PIV + 1).
• PITEN: Period Interval Timer Enabled
0 = The Periodic Interval Timer is disabled when the PIV value is reached.
1 = The Periodic Interval Timer is enabled.
• PITIEN: Periodic Interval Timer Interrupt Enable
0 = The bit PITS in PIT_SR has no effect on interrupt.
1 = The bit PITS in PIT_SR asserts interrupt.
31 30 29 28 27 26 25 24
––––––PITIENPITEN
23 22 21 20 19 18 17 16
–––– PIV
15 14 13 12 11 10 9 8
PIV
76543210
PIV
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15.4.2 Periodic Interval Timer Status Register
Register Name: PIT_SR
Access Type: Read-only
• PITS: Periodic Interval Timer Status
0 = The Periodic Interval timer has not reached PIV since the last read of PIT_PIVR.
1 = The Periodic Interval timer has reached PIV since the last read of PIT_PIVR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––PITS
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15.4.3 Periodic Interval Timer Value Register
Register Name: PIT_PIVR
Access Type: Read-only
Reading this register clears PITS in PIT_SR.
• CPIV: Current Periodic Interval Value
Returns the current value of the periodic interval timer.
• PICNT: Periodic Inte rval Counter
Returns the number of occurrences of periodic intervals since the last read of PIT_PIVR.
31 30 29 28 27 26 25 24
PICNT
23 22 21 20 19 18 17 16
PICNT CPIV
15 14 13 12 11 10 9 8
CPIV
76543210
CPIV
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15.4.4 Periodic Interval Timer Image Register
Register Name: PIT_PIIR
Access Type: Read-only
• CPIV: Current Periodic Interval Value
Returns the current value of the periodic interval timer.
• PICNT: Periodic Inte rval Counter
Returns the number of occurrences of periodic intervals since the last read of PIT_PIVR.
31 30 29 28 27 26 25 24
PICNT
23 22 21 20 19 18 17 16
PICNT CPIV
15 14 13 12 11 10 9 8
CPIV
76543210
CPIV
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16. Watchdog Timer (WDT)
16.1 Overview
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It features a
12-bit down counter that allows a watchdog period of up to 16 seconds (slow clock at 32.768 kHz). It can generate a
general reset or a processor reset only. In addition, it can be stopped while th e processor is in debug mode or idle mode.
16.2 Block Diagram
Figure 16-1. Watchdog Timer Block Diagram
=0
10
set
reset
read WDT_SR
or
reset
wdt_fault
(to Reset Controller)
set
reset
WDFIEN
wdt_int
WDT_MR
SLCK
1/128
12-bit Down
Counter
Current
Value
WDD
WDT_MR
<= WDD
WDV
WDRSTT
WDT_MR
WDT_CR
reload
WDUNF
WDERR
reload
write WDT_MR
WDT_MR
WDRSTEN
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16.3 Functional Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It is supplied
with VDDCORE. It restarts with initial values on processor reset.
The Watchdog is built around a 12-bit down counter, which is loaded with the value defined in the field WV of the Mode
Register (WDT_MR). The Watchdog Timer uses the Slow Clock divided by 128 to establish the maximum Watchdog
period to be 16 seconds (with a typical Slow Clock of 32.768 kHz).
After a Processor Reset, the value of WV is 0xFFF, corresponding to the maximum value of the counter with the external
reset generation enabled (field WDRSTEN at 1 after a Backup Reset). This means that a default Watchdog is running at
reset, i.e., at power-up. The user must either disable it (by setting the WDDIS bit in WDT_MR) if he does not expect to
use it or must reprogram it to meet the maximum Watchdog period the application requires.
The Watchdog Mode Register (WDT_MR) can be written only once. Only a processor reset resets it. Writing the
WDT_MR register reloads the timer with the newly programmed mode parameters.
If the watchdog is restarted by writing into the WDT_CR register, the WDT_MR register must not be programmed
during a period of time of 3 slow clock period following the WDT_CR write access. In any case, programming a
new value in WDT_MR automatically initiates a restart instruction.
In normal operation, the user reloads the Watchdog at regular intervals before the timer underflow occurs, by writing the
Control Register (WDT_CR) with the bit WDRSTT to 1. The Watchdog counter is then immediately reloaded from
WDT_MR and restarted, and the Slow Clock 128 divider is reset and restarted. The WDT_CR register is write-protected.
As a result, writing WDT_CR without the correct hard-coded key has no effect. If an underflow does occur, the “wdt_fault”
signal to the Reset Controller is asserted if the bit WDRSTEN is set in the Mode Register (WDT_MR). Moreover, the bit
WDUNF is set in the Watchdog Status Register (WDT_SR).
To prevent a software deadlock that continuously triggers the Watchdog, the reload of the Watchdog must occur while
the Watchdog counter is within a window between 0 and WDD, WDD is defined in the WatchDog Mode Register
WDT_MR.
Any attempt to restart the Watchdog while the Watchdog counter is between WDV and WDD results in a Watchdog error,
even if the Watchdog is disabled. The bit WDERR is updated in the WDT_SR and the “wdt_fault” signal to the Reset
Controller is asserted.
Note that this feature can be disabled by programming a WDD value greater than or equal to the WDV value. In such a
configuration, restarting the Watchdog Timer is permitted in the whole range [0; WDV] and does not generate an error.
This is the default configuration on reset (the WDD and WDV values are equal).
The status bits WDUNF (Watchdog Underflow) and WDERR (Watchdog Error) trigger an interrupt, provided the bit
WDFIEN is set in the mode register. The signal “wdt_fault” to the reset controller causes a Watchdog reset if the
WDRSTEN bit is set as already explained in the reset controller programmer Datasheet. In that case, the processor and
the Watchdog Timer are reset, and the WDERR and WDUNF flags are reset.
If a reset is generated or if WDT_SR is read, the status bits are reset, the interrupt is cleared, and the “wdt_fault” signal to
the reset controller is deasserted.
Writing the WDT_MR reloads and restarts the down counter.
While the processor is in debug state or in idle mode, the counter may be stopped depending on the value programmed
for the bits WDIDLEHLT and WDDBGHLT in the WDT_MR.
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Figure 16-2. Watchdog Behav io r
0
WDV
WDD
WDT_CR = WDRSTT
Watchdog
Fault
Normal behavior
Watchdog Error Watchdog Underflow
FFF if WDRSTEN is 1
if WDRSTEN is 0
Forbidden
Window
Permitted
Window
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16.4 Watchdog Timer (WDT) User Interface
16.4.1 Watchdog Timer Control Register
Register Name: WDT_CR
Access Type: Write-only
• WDRSTT: Watchdog Restart
0: No effect.
1: Restarts the Watchdog.
•KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
Table 16-1. Register Mapping
Offset Register Name Access Reset Value
0x00 Control Regist er WDT_CR Wr ite-only -
0x04 Mode Register WDT_MR Read-write Once 0x3FFF_2FFF
0x08 Status Register WDT_SR Read-only 0x0000_0000
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––WDRSTT
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16.4.2 Watchdog Timer Mode Register
Register Name: WDT_MR
Access Type: Read-write Once
• WDV: Watchdog Counter Value
Defines the value loaded in the 12-bit Watchdog Counter.
• WDFIEN: Watchdog Fault Interrupt Enable
0: A Watchdog fault (underflow or error) has no effect on interrupt.
1: A Watchdog fault (underflow or error) asserts interrupt.
• WDRSTEN: Watchdog Reset Enable
0: A Watchdog fault (underflow or error) has no effect on the resets.
1: A Watchdog fault (underflow or error) triggers a Watchdog reset.
• WDRPROC: Watchdog Reset Processor
0: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates all resets.
1: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates the processor reset.
• WDD: Watchdog Delta Value
Defines the permitted range for reloading the Watchdog Timer.
If the Watchdog Timer value is less than or equal to WDD, writing WDT_CR with WDRSTT = 1 restarts the timer.
If the Watchdog Timer value is greater than WDD, writing WDT_CR with WDRSTT = 1 causes a Watchdog error.
• WDDBGHLT: Watchdog Debug Halt
0: The Watchdog runs when the processor is in debug state.
1: The Watchdog stops when the processor is in debug state.
• WDIDLEHLT: Watchdog Idle Halt
0: The Watchdog runs when the system is in idle mode.
1: The Watchdog stops when the system is in idle state.
• WDDIS: Watchdog Disable
0: Enables the Watchdog Timer.
1: Disables the Watchdog Timer.
Note: The WDD and WDV values must not be modified within three slow clock periods after a restart of the watchdog performed by a
write access in WDT_CR; otherwise, the watchdog may trigger an end of period earlier than expected.
31 30 29 28 27 26 25 24
– – WDIDLEHLT WDDBGHLT WDD
23 22 21 20 19 18 17 16
WDD
15 14 13 12 11 10 9 8
WDDIS WDRPROC WDRSTEN WDFIEN WDV
76543210
WDV
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16.4.3 Watchdog Timer Status Register
Register Name: WDT_SR
Access Type: Read-only
• WDUNF: Watchdog Underflow
0: No Watchdog underflow occurred since the last read of WDT_SR.
1: At least one Watchdog underflow occurred since the last read of WDT_SR.
• WDERR: Watchdog Error
0: No Watchdog error occurred since the last read of WDT_SR.
1: At least one Watchdog error occurred since the last read of WDT_SR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––WDERRWDUNF
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17. Voltage Regulator Mode Controller (VREG)
17.1 Overview
The Voltage Regulator Mode Controller contains one Read-write register, the Voltage Regulator Mode Register. Its offset
is 0x60 with respect to the System Controller offset.
This register controls the Voltage Regulator Mode. Setting PSTDBY (bit 0) puts the Voltage Regulator in Standby Mode
or Low-power Mode. On reset, the PSTDBY is reset, so as to wake up the Voltage Regulator in Normal Mode.
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17.2 Voltage Regulator Power Controller (VREG) User Interface
17.2.1 Voltage Regulator Mode Register
Register Name: VREG_MR
Access Type: Read-write
• PSTDBY: Periodic Interval Value
0 = Voltage regulator in normal mode.
1 = Voltage regulator in standby mode (low-power mode).
Table 17-1. Register Mapping
Offset Register Name Access Reset Value
0x60 Voltage Regulator Mode Register VREG_MR Read-write 0x0
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––PSTDBY
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18. Memory Controller (MC)
18.1 Overview
The Memory Controller (MC) manages the ASB bus and controls accesses requested by the masters, typically the ARM7TDMI
processor and the Peripheral DMA Controller. It features a bus arbiter, an address decoder, an abort status, a misalignment
detector and an Embedded Flash Controller.
18.2 Block Diagram
Figure 18-1. Memory Controller Block Diagram
18.3 Functional Description
The Memory Controller handles the internal ASB bus and arbitrates the accesses of up to three masters.
ARM7TDMI
Processor
Bus
Arbiter
Peripheral
DMA
Controller
Memory Controller
Abort
ASB
Abort
Status
Address
Decoder
User
Interface
Peripheral 0
Peripheral 1
Internal
RAM
APB
APB
Bridge
Misalignment
Detector
From Master
to Slave
Peripheral N
Embedded
Flash
Controller
Internal
Flash
EMAC
DMA
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It is made up of:
A bus arbiter
An address decoder
An abort status
A misalignment detector
An Embedded Flash Controller
The MC handles only little-endian mode accesses. The masters work in little-endian mode only.
18.3.1 Bus Arbiter
The Memory Controller has a simple, hard-wired priority bus arbiter that gives the control of the bus to one of the three
masters. The EMAC has the highest priority; the Peripheral DMA Controller has the medium priority; the ARM processor
has the lowest one.
18.3.2 Address Decoder
The Memory Controller features an Address Decoder that first decodes the four highest bits of the 32-bit address bus
and defines three separate areas:
One 256-Mbyte address space for the internal memories
One 256-Mbyte address space reserved for the embedded peripherals
An undefined address space of 3584M bytes representing fourteen 256-Mbyte areas that return an Abort if
accessed
Figure 18-2 shows the assignment of the 256-Mbyte memory areas.
Figure 18-2. Memory Areas
18.3.2.1 Internal Memory Mapping
Within the Internal Memory address space, the Address Decoder of the Memory Controller decodes eight more address
bits to allocate 1-Mbyte address spaces for the embedded memories.
The allocated memories are accessed all along the 1-Mbyte address space and so are repeated n times within this
address space, n equaling 1M bytes divided by the size of the memory.
When the address of the access is undefined within the internal memory area, the Address Decoder returns an Abort to
the master.
0x0000 0000
0x0FFF FFFF
0x1000 0000
0xEFFF FFFF
0xF000 0000
0xFFFF FFFF
256M Bytes
256M Bytes
14 x 256MBytes
3,584 Mbytes
Internal Memories
Undefined
(Abort)
Peripherals
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Figure 18-3. Internal Memory Mapping
18.3.2.2 Internal Memory Area 0
The first 32 bytes of Internal Memory Area 0 contain the ARM processor exception vectors, in particular, the Reset
Vector at address 0x0.
Before execution of the remap command, the on-chip Flash is mapped into Internal Memory Area 0, so that the
ARM7TDMI reaches an executable instruction contained in Flash. After the remap command, the internal SRAM at
address 0x0020 0000 is mapped into Internal Memory Area 0. The memory mapped into Internal Memory Area 0 is
accessible in both its original location and at address 0x0.
18.3.3 Remap Command
After execution, the Remap Command causes the Internal SRAM to be accessed through the Internal Memory Area 0.
As the ARM vectors (Reset, Abort, Data Abort, Prefetch Abort, Undefined Instruction, Interrupt, and Fast Interrupt) are
mapped from address 0x0 to address 0x20, the Remap Command allows the user to redefine dynamically these vectors
under software control.
The Remap Command is accessible through the Memory Controller User Interface by writing the MC_RCR (Remap
Control Register) RCB field to one.
The Remap Command can be cancelled by writing the MC_RCR RCB field to one, which acts as a toggling command.
This allows easy debug of the user-defined boot sequence by offering a simple way to put the chip in the same
configuration as after a reset.
18.3.4 Abort Status
There are two reasons for an abort to occur:
access to an undefined address
an access to a misaligned address.
When an abort occurs, a signal is sent back to all the masters, regardless of which one has generated the access.
However, only the ARM7TDMI can take an abort signal into account, and only under the condition that it was generatin g
an access. The Peripheral DMA Controller and the EMAC do not handle the abort input signal. Note that the connections
are not represented in Figure 18-1.
To facilitate debug or for fault analysis by an operating system, the Memory Controller integrates an Abort Status register
set.
The full 32-bit wide abort address is saved in MC_AASR. Parameters of the access are saved in MC_ASR and include:
the size of the request (field ABTSZ)
256M Bytes
Internal Memory Area 0
Undefined Areas
(Abort)
0x000F FFFF
0x001F FFFF
0x002F FFFF
0x0FFF FFFF
1 M Bytes
1 M Bytes
1 M Bytes
252 M Bytes
Internal Memory Area 1
Internal Flash
Internal Memory Area 2
Internal SRAM
0x0000 0000
0x0010 0000
0x0020 0000
0x0030 0000 Internal Memory Area 3
Internal ROM
0x003F FFFF
0x0040 0000
1 M Bytes
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the type of the access, whether it is a data read or write, or a code fetch (field ABTTYP)
whether the access is due to accessing an undefined address (bit UNDADD) or a misaligned address (bit
MISADD)
the source of the access leading to the last abort (bits MST_EMAC, MST_PDC and MST_ARM)
whether or not an abort occurred for each master since the last read of the register (bits SVMST_EMAC,
SVMST_PDC and SVMST_ARM) unless this information is loaded in MST bits
In the case of a Data Abort from the processor, the address of the data access is stored. This is useful, as searching for
which address generated the abort would require disassembling the instructions and full knowledge of the processor
context.
In the case of a Prefetch Abort, the address may have changed, as the prefetch abort is pipelined in the ARM processor.
The ARM processor takes the prefetch abort into account only if the read instruction is executed and it is probable that
several aborts have occurred during this time. Thus, in this case, it is preferable to use the content of the Abort Link
register of the ARM processor.
18.3.5 Embedded Flash Controller
The Embedded Flash Controller is added to the Memory Controller and ensures the interface of the flash block with the
32-bit internal bus. It allows an increase of performance in Thumb Mode for Code Fetch with its system of 32-bit buffers.
It also manages with the programming, erasing, locking and unlocking sequences thanks to a full set of commands.
18.3.6 Misalignment Detector
The Memory Controller features a Misalignment Detector that checks the consistency of the accesses.
For each access, regardless of the master, the size of the access and the bits 0 and 1 of the address bus are checked. If
the type of access is a word (32-bit) and the bits 0 and 1 are not 0, or if the type of the access is a half-word (16-bit) and
the bit 0 is not 0, an abort is returned to the master and the access is cancelled. Note that the accesses of the ARM
processor when it is fetching instructions are not checked.
The misalignments are generally due to software bugs leading to wrong pointer handling. These bugs are particularly
difficult to detect in the debug phase.
As the requested address is saved in the Abort Status Register and the address of the instruction generating the
misalignment is saved in the Abort Link Register of the processor, detection and fix of this kind of software bugs is
simplified.
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18.4 Memory Controller (MC) User Interface
Base Address: 0xFFFFFF00
Note: 1. EFC1 pertains to AT91SAM7X512 only.
Table 18-1. Regist er Mapping
Offset Register Name Access Reset St ate
0x00 MC Remap Control Register MC_RCR Write-only
0x04 MC Abort Status Register MC_ASR Read-only 0x0
0x08 MC Abort Address Status Register MC_AASR Read-only 0x0
0x10-0x5C Reserved
0x60 EFC0 Configuration Registers See the Embedded Flash Controller Se ction
0x70 EFC1(1) Configuration Registers
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18.4.1 MC Remap Control Register
Register Name: MC_RCR
Access Type: Write-only
Offset:0x0
• RCB: Remap Command Bit
0: No effect.
1: This Command Bit acts on a toggle basis: writing a 1 alternatively cancels and restores the remapping of the page zero mem-
ory devices.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––RCB
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18.4.2 MC Abort Status Register
Register Name:MC_ASR
Access Type: Read-only
Reset Value:0x0
Offset: 0x04
• UNDAD D: Undefined Address Abor t Status
0: The last abort was not due to the access of an undefined address in the address space.
1: The last abort was due to the access of an undefined address in the address space.
• MISADD: Misaligned Address Abort Status
0: The last aborted access was not due to an address misalignment.
1: The last aborted access was due to an address misalignment.
• ABTSZ: Abort Size Status
• ABTTYP: Abort Type Status
• MST_EMAC: EMAC Abort Source
0: The last aborted access was not due to the EMAC.
1: The last aborted access was due to the EMAC.
31 30 29 28 27 26 25 24
– – – – – SVMST_ARM SVMST_PDC SVMST_EMAC
23 22 21 20 19 18 17 16
– – – – – MST_ARM MST_PDC MST_EMAC
15 14 13 12 11 10 9 8
– – – – ABTTYP ABTSZ
76543 2 1 0
––––– –MISADDUNDADD
ABTSZ Abort Size
00 Byte
01 Half-word
10 Word
11 Reserved
ABTTYP Abort Type
0 0 Data Read
0 1 Data Write
1 0 Code Fetch
11 Reserved
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• MST_PDC: PDC Abort Source
0: The last aborted access was not due to the PDC.
1: The last aborted access was due to the PDC.
• MST_ARM : ARM Abort Source
0: The last aborted access was not due to the ARM.
1: The last aborted access was due to the ARM.
• SVMST_EMAC: Saved EMAC Abor t Source
0: No abort due to the EMAC occurred since the last read of MC_ASR or it is notified in the bit MST_EMAC.
1: At least one abort due to the EMAC occurred since the last read of MC_ASR.
• SVMST_PDC: Saved PDC Abort Source
0: No abort due to the PDC occurred since the last read of MC_ASR or it is notified in the bit MST_PDC.
1: At least one abort due to the PDC occurred since the last read of MC_ASR.
• SVMST_ARM: Saved ARM Abort Source
0: No abort due to the ARM occurred since the last read of MC_ASR or it is notified in the bit MST_ARM.
1: At least one abort due to the ARM occurred since the last read of MC_ASR.
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18.4.3 MC Abort Address Status Register
Register Name: MC_AASR
Access Type: Read-only
Reset Value:0x0
Offset: 0x08
• ABTADD: Abort Address
This field contains the address of the last aborted access.
31 30 29 28 27 26 25 24
ABTADD
23 22 21 20 19 18 17 16
ABTADD
15 14 13 12 11 10 9 8
ABTADD
76543210
ABTADD
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19. Embedded Flash Controller (EFC)
19.1 Overview
The Embedded Flash Controller (EFC ) is a part of the Memory Controller and ensures the interface of the Flash block
with the 32-bit internal bus. It increases performance in Thumb Mode for Code Fetch with its system of 32-bit buffers. It
also manages the programming, erasing, locking and unlocking sequences using a full set of commands.
The AT91SAM7X512 is equipped with two EFCs, EFC0 and EFC1. EFC1 does not feature the Security bit and GPNVM
bits. The Security and GPNVM bits embedded only on EFC0 apply to the two blocks in the AT91SAM7X512.
19.2 Functional Description
19.2.1 Embedded Flash Organization
The Embedded Flash interfaces directly to the 32-bit internal bus. It is composed of several interfaces:
One memory plane organized in several pages of the same size
Two 32-bit read buffers used for code read optimization (see “Read Operations” on page 100).
One write buffer that manages page programming. The write buffer size is equal to the page size. This buffer is
write-only and accessible all along the 1 MByte address space, so that each word can be written to its final
address (see “Write Operations” on page 102).
Several lock bits used to protect write and erase operations on lock regions. A lock region is composed of several
consecutive pages, and each lock region has its associated lock bit.
Several general-purpose NVM bits . Each bit controls a specific feature in the device. Refer to the product definition
section to get the GPNVM assignment.
The Embedded Flash size, the page size and the lock region organization are described in the product definition section.
Table 19-1 . Product Specific Lock and General-purpose NVM Bits
SAM7X512 SAM7X256 SAM7X128 Denomination
3 3 3 Number of General-purpose NVM bits
32 16 8 Number of Lock Bits
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Figure 19-1. Embedded Flas h Me mory Mapping
19.2.2 Read Operations
An optimized controller manages embedded Flash reads. A system of 2 x 3 2-bit buff ers is added in order to start access
at following address during the second read, thus increasing performance when the processor is running in Thumb mode
(16-bit instruction set). See Figure 19-2, Figure 19-3 and Figure 19-4.
This optimization concerns only Code Fetch and not Data.
The read operations can be performed with or without wait state. Up to 3 wait states can be programmed in the field FWS
(Flash Wait State) in the Flash Mode Register MC_FMR (see “MC Flash Mode Register” on page 108). Definin g FWS to
be 0 enables the single-cycle access of the embedded Flash.
The Flash memory is accessible through 8-, 16- and 32-bit reads.
As the Flash block size is smaller than the address space reserved for the internal memory area, the embedded Flash
wraps around the address space and appears to be repeated within it.
Lock Region 0
Lock Region
(n-1)
Page 0
Page (m-1)
Start Address
32-bit wide
Flash Memory
Page ( (n-1)*m )
Page (n*m-1)
Lock Bit 0
Lock Region 1 Lock Bit 1
Lock Bit n-1
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Figure 19-2. Code Read O ptimization in Thumb Mode for FWS = 0
Note: When FWS is equal to 0, all accesses are perfor m ed in a single-cycle access.
Figure 19-3. Code Read O ptimization in Thumb Mode for FWS = 1
Note: When FWS is equal to 1, in case of sequential reads, all the accesses are performed in a single-cycle access (except
for the first one).
Flash Access
Buffer (32 bits)
Master Clock
ARM Request (16-bit)
Code Fetch
Data To ARM
Bytes 0-3 Bytes 4-7
Bytes 0-3
Bytes 0-1 Bytes 2-3 Bytes 4-5 Bytes 6-7 Bytes 8-9 Bytes 10-11 Bytes 12-13
@Byte 0 @Byte 2 @Byte 4 @Byte 6 @Byte 8 @Byte 10 @Byte 12 @Byte 14 @Byte 16
Bytes 14-15
Bytes 4-7
Bytes 8-11
Bytes 8-11
Bytes 12-15 Bytes 16-19
Bytes 12-15
Flash Access
Buffer (32 bits)
Master Clock
ARM Request (16-bit)
Code Fetch
Data To ARM
Bytes 0-3 Bytes 4-7
Bytes 0-3
Bytes 2-3 Bytes 4-5 Bytes 6-7 Bytes 8-9 Bytes 10-11
@Byte 0 @Byte 4 @Byte 6 @Byte 8 @Byte 10 @Byte 12 @Byte 14
Bytes 4-7
Bytes 8-11
Bytes 8-11
Bytes 12-15
1 Wait State Cycle
Bytes 0-1
1 Wait State Cycle 1 Wait State Cycle 1 Wait State Cycle
@Byte 2
Bytes 12-13
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Figure 19-4. Code Read O ptimization in Thumb Mode for FWS = 3
Note: When FWS is equal to 2 or 3, in case of sequential reads, the first access takes FWS cycles, the second access one
cycle, the third access FWS cycles, the fourth access one cycle, etc.
19.2.3 Write Operations
The internal memory area reserved for the embedded Flash can also be written through a write-only latch buffer. Write
operations take into account only the 8 lowest address bits and thus wrap around within the internal memory area
address space and appear to be repeated 1024 times within it.
Write operations can be prevented by programming the Memory Protection Unit of the product.
Writing 8-bit and 16-bit data is not allowed and may lead to unpredictable data corruption.
Write operations are performed in the number of wait states equal to the number of wait states for read operations + 1,
except for FWS = 3 (see “MC Flash Mode Register” on page 108).
19.2.4 Flash Commands
The EFC offers a command set to manage programming the memory flash, locking and unlocking lock sectors,
consecutive programming and locking, and full Flash erasing.
To run one of these commands, the field FCMD of the MC_FCR register has to be written with the command number. As
soon as the MC_FCR register is written, the FRDY flag is automatically cleared. Once the current command is achieved,
then the FRDY flag is automatically set. If an interrupt has been enabled by setting the bit FRDY in MC_FMR, the
interrupt line of the Memory Controller is activated.
Flash Access
Master Clock
Data To ARM 0-1
@Byte 0 @2
Bytes 0-3 Bytes 4-7 Bytes 8-11 Bytes 12-15
Bytes 0-3
2-3 6-7
@4
8-9 10-11
4-5
@8 @12
Bytes 4-7
3 Wait State Cycles
Buffer (32 bits)
ARM Request (16-bit)
Code Fetch
Bytes 8-11
3 Wait State Cycles 3 Wait State Cycles 3 Wait State Cycles
@6 @10
12-13
Table 19-2 . Set of Commands
Command Value Mnemonic
Write page 0x01 WP
Set Lock Bit 0x02 SLB
Write Page and Lock 0x03 WPL
Clear Lock Bit 0x04 CLB
Erase all 0x08 EA
Set General-purpose NVM Bit 0x0B SGPB
Clear General-purpose NVM Bit 0x0D CGPB
Set Security Bit 0x0F SSB
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All the commands are protected by the same keyword, which has to be written in the eight highest bits of the MC_FCR
register.
Writing MC_FCR with data that does not contain the correct key and/or with an invalid command has no effect on the
memory plane; however, the PROGE flag is set in the MC_FSR register. This flag is automatically cleared by a read
access to the MC_FSR register.
When the current command writes or erases a page in a locked region, the command has no effect on the whole memory
plane; however, the LOCKE flag is set in the MC_FSR register . This flag is automatically cleared by a read access to the
MC_FSR register.
Figure 19-5. Command State Chart
In order to guarantee valid operations on the Flash memory, the field Flash Microsecond Cycle Number (FMCN) in the
Flash Mode Register MC_FMR must be correctly programmed (see “MC Flash Mode Register” on page 108).
19.2.4.1 Flash Programming
Several commands can be used to program the Flash.
Check if FRDY flag set No
Yes
Read Status: MC_FSR
Write FCMD and PAGENB in MC_FCR
Check if LOCKE flag set
Check if FRDY flag set No
Read Status: MC_FSR
Yes
Yes Locking region violation
No
Check if PROGE flag set Yes
No
Bad keyword violation and/or Invalid command
Command Successful
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The Flash technology requires that an erase must be done before programming. The entire memory plane can be erased
at the same time, or a page can be automatically erased by clearing the NEBP bit in the MC_FMR register before writing
the command in the MC_FCR register.
By setting the NEBP bit in the MC_FMR register, a page can be programmed in several steps if it has been erased
before (see Figure 19-6).
Figure 19-6. Example of Partial Page Programming
The Partial Programming mode works only with 32-bit (or higher) boundaries. It cannot be used with boundaries lower
than 32 bits (8 or 16-bit for example).
After programming, the page (the whole lock region) can be locked to prevent miscellaneous write or erase sequences.
The lock bit can be automatically set after page programming using WPL.
Data to be written are stored in an internal latch buffer. The size of the latch buffer corresponds to the page size. The
latch buffer wraps around within the internal memory area address space and appears to be repeated by the number of
pages in it.
Note: Writing of 8-bit and 16-bit data is not allowed and may lead to unpredictable data corruption.
Data are written to the latch buffer before the programming command is written to the Flash Command Register
MC_FCR. The sequence is as follows:
Write the full page, at any page address, within the internal memory area address space using only 32-bit access.
Programming starts as soon as the page number and the programming command are written to the Flash
Command Register. The FRDY bit in the Flash Programming Status Register (MC_FSR) is automatically cleared.
When programming is completed, the bit FRDY in the Flash Programming Status Register (MC_FSR) rises. If an
interrupt was enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is activated.
Two errors can be detected in the MC_FSR register after a programming sequence:
Programming Error: A bad keyword and/or an invalid command have been written in the MC_FCR register.
Lock Error: The page to be programmed belongs to a locked region. A command must be previously run to u nlock
the corresponding region.
19.2.4.2 Erase All Command
The entire memory can be erased if the Erase All Command (EA) in the Flash Command Register MC_FCR is written.
Erase All operation is allowed only if there are no lock bits set. Thus, if at least one lock region is locked, the bit LOCKE
in MC_FSR rises and the command is cancelled. If the bit LOCKE has been written at 1 in MC_FMR, the interrupt line
rises.
Erase All Flash Programming of the second part of Page 7 Programming of the third part of Page 7
32 bits wide 32 bits wide 32 bits wide
16 words
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
...
CA FE CA FE
CA FE CA FE
CA FE CA FE
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF CA FE CA FE
CA FE CA FE
CA FE CA FE
DE CA DE CA
DE CA DE CA
DE CA DE CA
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
FF FF FF FF
Step 1. Step 2. Step 3.
...
...
...
...
...
...
...
...
...
...
...
(NEBP = 1) (NEBP = 1)
16 words
16 words
16 words
Page 7 erased
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When programming is complete, the bit FRDY bit in the Flash Programming Status Register (MC_FSR) rises. If an
interrupt has been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is activated.
Two errors can be detected in the MC_FSR register after a programming sequence:
Programming Error: A bad keyword and/or an invalid command have been written in the MC_FCR register.
Lock Error: At least one lock region to be erased is protected. The erase command has been refused and no page
has been erased. A Clear Lock Bit command must be executed previously to unlock the corresponding lock
regions.
19.2.4.3 Lock Bit Protection
Lock bits are associated with several pages in the embedded Flash memory plane. This defines lock regions in the
embedded Flash memory plane. They prevent writing/erasing protected pages.
After production, the device may have some embedded Flash lock regio ns locked. These locked regions are reserved for
a default application. Refer to the product definition section for the default embedded Flash mapping. Locked sectors can
be unlocked to be erased and then programmed with another application or other data.
The lock sequence is:
The Flash Command register must be written with the following value:
(0x5A << 24) | (lockPageNumber << 8 & PAGEN) | SLB
lockPageNumber is a page of the corresponding lock region.
When locking completes, the bit FRDY in the Flash Programming Status Register (MC_FSR) rises. If an interrupt
has been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is activated.
A programming error, where a bad keyword and/or an invalid command have been written in the MC_FCR register, may
be detected in the MC_FSR register after a programming sequence.
It is possible to clear lock bits that were set previously. Then the locked region can be erased or programmed. The unlock
sequence is:
The Flash Command register must be written with the following value:
(0x5A << 24) | (lockPageNumber << 8 & PAGEN) | CLB
lockPageNumber is a page of the corresponding lock region.
When the unlock completes, the bit FRDY in the Flash Programming Status Register (MC_FSR) rises. If an
interrupt has been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is
activated.
A programming error, where a bad keyword and/or an invalid command have been written in the MC_FCR register, may
be detected in the MC_FSR register after a programming sequence.
The Unlock command programs the lock bit to 1; the corresponding bit LOCKSx in MC_FSR reads 0. The Lock
command programs the lock bit to 0; the corresponding bit LOCKSx in MC_FSR reads 1.
Note: Access to the Flash in Read Mode is permitted when a Lock or Unlock command is performed.
19.2.4.4 General-purpose NVM Bits
General-purpose NVM bits do not interfere with the embedded Flash memory plane. (Does not apply to EFC1 on the
AT91SAM7X512.) These general-purpose bits are dedicated to protect other parts of the product. They can be set
(activated) or cleared individually. Refer to the product definition section for the general-purpose NVM bit action.
The activation sequence is:
Start the Set General Purpose Bit command (SGPB) by writing the Flash Command Register with the SEL
command and the number of the general-purpose bit to be set in the PAGEN field.
When the bit is set, the bit FRDY in the Flash Programming Status Register (MC_FSR) rises. If an interrupt has
been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is activated.
Two errors can be detected in the MC_FSR register after a programming sequence:
Programming Error: A bad keyword and/or an invalid command have been written in the MC_FCR register
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If the general-purpose bit number is greater than the total number of general-purpose bits, then the command has
no effect.
It is possible to deactivate a general-purpose NVM bit set previously. The clear sequence is:
S tart the Clear General-purpose Bit command (CGPB) by writing the Flash Command Register with CGPB a nd the
number of the general-purpose bit to be cleared in the PAGEN field.
When the clear completes, the bit FRDY in the Flash Programming S tatus Register (MC_FSR) rises. If an interrupt
has been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is activated.
Two errors can be detected in the MC_FSR register after a programming sequence:
Programming Error: a bad keyword and/or an invalid command have been written in the MC_FCR register
If the number of the general-purpose bit set in the P AGEN field is greater than the total numb er of general-purpose
bits, then the command has no effect.
The Clear General-purpose Bit command programs the general-purpose NVM bit to 0; the corresponding bit GPNVM0 to
GPNVMx in MC_FSR reads 0. The Set General-purpose Bit command programs the general-purpose NVM bit to 1; the
corresponding bit GPNVMx in MC_FSR reads 1.
Note: Access to the Flash in read mode is permitted when a Set, Clear or Get General-purpose NVM Bit command is
performed.
19.2.4.5 Security Bit
The goal of the security bit is to prevent external access to the internal bus system. (Does not apply to EFC1 on the
AT91SAM7X512.) JTAG, Fast Flash Programming and Flash Serial Test Interface features are disabled. Once set, this
bit can be reset only by an external hardware ERASE request to the chip. Refer to the product definition section for the
pin name that controls the ERASE. In this case, the full memory plane is erased and all lock and general-purpose NVM
bits are cleared. The security bit in the MC_FSR is cleared only after these operations. The activation sequence is:
Start the Set Security Bit command (SSB) by writing the Flash Command Register.
When the locking completes, the bit FRDY in the Flash Programming Status Register (MC_FSR) rises. If an
interrupt has been enabled by setting the bit FRDY in MC_FMR, the interrupt line of the Memory Controller is
activated.
When the security bit is active, the SECURITY bit in the MC_FSR is set.
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19.3 Embedded Flash Controller (EFC ) User Interface
The User Interface of the EFC is integrated within the Memory Controller with Base Address: 0xFFFF FF00.
The AT91SAM7X512 is equipped with two EFCs, EFC0 and EFC1, as described in the Register Mapping tables and Register
descriptions that follow.
Table 19-3. Embedded Flash Controller (EFC0) Register Mapping
Offset Register Name Access Reset St ate
0x60 MC Flash Mode Register MC_FMR Read-write 0x0
0x64 MC Flash Command Reg ister MC_FCR Write-only –
0x68 MC Flash St atus Register MC_FSR Read-only –
0x6C Reserved – – –
Table 19-4. Embedded Flash Controller (EFC1) Register Mapping
Offset Register Name Access Reset St ate
0x70 MC Flash Mode Register MC_FMR Read-write 0x0
0x74 MC Flash Command Reg ister MC_FCR Write-only –
0x78 MC Flash St atus Register MC_FSR Read-only –
0x7C Reserved – – –
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19.3.1 MC Flash Mode Register
Register Name:MC_FMR
Access Type: Read-write
Offset: (EFC0) 0x60
Offset: (EFC1) 0x70
• FRDY: Flash Ready Interrupt Enable
0: Flash Ready does not generate an interrupt.
1: Flash Ready generates an interrupt.
• LOCKE: Lock Error Interrupt Enable
0: Lock Error does not generate an interrupt.
1: Lock Error generates an interrupt.
• PROGE: Programming Error Interrupt Enable
0: Programming Error does not generate an interrupt.
1: Programming Error generates an interrupt.
• NEBP: No Erase Before Programming
0: A page erase is performed before programming.
1: No erase is performed before programming.
• FWS: Flash Wait State
This field defines the number of wait states for read and write operations:
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FMCN
15 14 13 12 11 10 9 8
–––––– FWS
76543210
NEBP – – – PROGE LOCKE – FRDY
FWS Read Operations Write Operations
0 1 cycle 2 cycles
1 2 cycles 3 cycles
2 3 cycles 4 cycles
3 4 cycles 4 cycles
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• FMCN: Flash Microsecond Cycle Number
Before writing Non Volatile Memory bits (Lock bits, General Purpose NVM bit and Security bits), this field must be set to the num-
ber of Master Clock cycles in one microsecond.
When writing the rest of the Flash, this field defines the number of Master Clock cycles in 1.5 microseconds. This number mu st be
rounded up.
Warning: The value 0 is only allowed for a master clock period superior to 30 microseconds.
Warning: In order to guarantee valid operations on the flash memory, the field Flash Microsecond Cycle Number (FMCN) must
be correctly programmed.
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19.3.2 MC Flash Command Register
Register Name:MC_FCR
Access Type: Write-only
Offset: (EFC0) 0x64
Offset: (EFC1) 0x74
• FCMD: Flash Command
This field defines the Flash commands:
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
–––––– PAGEN
15 14 13 12 11 10 9 8
PAGEN
76543210
–––– FCMD
FCMD Operations
0000 No command.
Does not raise the Programming Error Status flag in the Flash Status Register MC_FSR.
0001 Write Page Command (WP):
Starts the programming of the page specified in the PAGEN field.
0010 Set Lock Bit Command (SLB):
Starts a set lock bit sequence of the lock region specified in the PAGEN field.
0011 Write Page and Lock Command (WPL):
The lock sequence of the lock region associated with the page specified in the field PAGEN
occurs automatically after completion of the programming sequence.
0100 Clear Lock Bit Command (CLB):
Starts a clear lock bit sequence of the lock region specified in the PAGEN field.
1000 Erase All Command (EA):
Starts the erase of the entire Flash.
If at least one page is locked, the command is cancelled.
1011 Set General-purpose NVM Bit (SGPB):
Activates the general-purpose NVM bit corresponding to the number specified in the PAGEN
field.
1101 Clear General Purpose NVM Bit (CGPB):
Deactivates the general-purpose NVM bit correspond ing to the number specified in the
PAGEN field.
1111 Set Security Bit Command (SSB):
Sets security bit.
Others Reserved.
Raises the Programming Error Status flag in the Flash Status Register MC_FSR.
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•PAGEN: Page Number
Note: Depending on the command, all the possible unused bits of PAGEN are meaningless.
• KEY: Write Protection Key
This field should be written with the value 0x5A to enable the command defined by the bits of the register. If the field is written with
a different value, the write is not performed and no action is started.
Command PAGEN Description
Write Page Command PAGEN defines the page number to be written.
Write Page and Lock Command PAGEN defines the page number to be written and its associated
lock region.
Erase All Command This field is meaningless
Set/Clear Lock Bit Command PAGEN defines one page number of the lock region to be locked or
unlocked.
Set/Clear General Purpose NVM Bit Command PAGEN defines the general-purpose bit number .
Set Security Bit Command This field is meaningless
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19.3.3 MC Flash Status Register
Register Name:MC_FSR
Access Type: Read-only
Offset: (EFC0) 0x68
Offset: (EFC1) 0x78
• FRDY: Flash Ready Status
0: The EFC is busy and the application must wait before running a new command.
1: The EFC is ready to run a new command.
• LOCKE: Lock Error Status
0: No programming of at least one locked lock region has happened since the last read of MC_FSR.
1: Programming of at least one locked lock region has happened since the last read of MC_FSR.
• PROGE: Programming Error Status
0: No invalid commands and no bad keywords were written in the Flash Command Register MC_FCR.
1: An invalid command and/or a bad keyword was/were written in the Flash Command Register MC_FCR.
• SECURITY: Security Bit Status (Does not apply to EFC1 on the AT91SAM7X512.)
0: The security bit is inactive.
1: The security bit is active.
• GPNVMx: General-purpose NVM Bit Status (Does not ap ply to EFC1 on the AT91SAM7X512.)
0: The corresponding general-purpose NVM bit is inactive.
1: The corresponding general-purpose NVM bit is active.
• EFC LOCKSx: Lock Region x Lock Status
0: The corresponding lock region is not locked.
1: The corresponding lock region is locked.
31 30 29 28 27 26 25 24
LOCKS15 LOCKS14 LOCKS13 LOCKS12 LOCKS11 LOCKS10 LOCKS9 LOCKS8
23 22 21 20 19 18 17 16
LOCKS7 LOCKS6 LOCKS5 LOCKS4 LOCKS3 LOCKS2 LOCKS1 LOCKS0
15 14 13 12 11 10 9 8
–––––GPNVM2 GPNVM1 GPNVM0
76543210
– – – SECURITY PROGE LOCKE – FRDY
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20. Fast Flash Programming Interface (FFPI)
20.1 Overview
The Fast Flash Programming Interface provides two solutions - parallel or serial - for high-volume programming using a
standard gang programmer. The parallel interface is fully handshaked and the device is considered to be a standard
EEPROM. Additionally, the parallel protocol offers an optimized access to all the embedded Flash functionalities. The
serial interface uses the standard IEEE 1149.1 JTAG protocol. It offers an optimized access to all the embedded Flash
functionalities.
Although the Fast Flash Programming Mode is a ded icated mode for high volume programming, this mode not designed
for in-situ programming.
20.2 Parallel Fast Flash Programming
20.2.1 Device Configuration
In Fast Flash Programming Mode, the device is in a specific test mode. Only a certain set of pins is significant, the rest of
the PIOs are used as inputs with a pull-up. The crystal oscillator is in bypass mode. Other pins must be left unconnected.
Figure 20-1. Parallel Programming Interface
NCMD PGMNCMD
RDY PGMRDY
NOE PGMNOE
NVALID PGMNVALID
MODE[3:0] PGMM[3:0]
DATA[15:0] PGMD[15:0]
XIN
TST
VDDIO PGMEN0
PGMEN1
0 - 50MHz
VDDIO
VDDCORE
VDDIO
VDDPLL
VDDFLASH
GND
VDDIO
Table 20-1. Signal Descriptio n List
Signal Name Function Type Active
Level Comments
Power
VDDFLASH Flash Power Supply Power
VDDIO I/O Lines Power Supply Power
VDDCORE Core Power Supply Power
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20.2.2 Signal Names
Depending on the MODE settings, DATA is latched in different internal registers.
When MODE is equal to CMDE, then a new command (strobed on DATA[15:0] signals) is stored in the command
register.
VDDPLL PLL Power Supply Power
GND Ground Ground
Clocks
XIN
Main Clock Input.
This input can be tied to GND. In this
case, the device is clocked by the internal
RC oscillator.
Input 32KHz to 50MHz
Test
TST Test Mode Select Input High Must be connected to VDDIO
PGMEN0 Test Mode Select Input High M ust be connected to VDDIO
PGMEN1 Test Mode Select Input High M ust be connected to VDDIO
PIO
PGMNCMD Valid command available Input Low Pulled-up input at reset
PGMRDY 0: Device is busy
1: Device is ready for a new command Output High Pu lled-up input at reset
PGMNOE Output Enable (active high) Input Low Pulled-up input at reset
PGMNVALID 0: DATA[15:0] is in input mode
1: DATA[15:0] is in output mode Output Low Pulled- up input at reset
PGMM[3:0] Specifies DATA type (See Table 20-2) Input Pulled-up input at reset
PGMD[15:0] Bi-directional data bus Input/Output Pulled-up input at reset
Tabl e 20-1. Sig nal Description List (Continued)
Signal Name Function Type Active
Level Comments
Table 20-2. Mode Coding
MODE[3:0] Symbol Data
0000 CMDE Command Register
0001 ADDR0 Address Register LSBs
0010 ADDR1
0101 DATA Data Register
Default IDLE No register
Table 20-3. Command Bit Coding
DATA[15:0] Symbol Command Executed
0x0011 READ Read Flash
0x0012 WP Write Page Flash
0x0022 WPL Write Page and Lock Flash
0x0032 EWP Erase Page and Write Page
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Note: 1. Applies to AT91SAM7X512.
20.2.3 Entering Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
Apply GND, VDDIO, VDDCORE, VDDFLASH and VDDPLL.
Apply XIN clock within TPOR_RESET if an external clock is available.
Wait for TPOR_RESET
Start a read or write handshaking.
Note: After reset, the device is clocked by the internal RC oscillator . Before clearing RDY signal, if an external clock ( >
32 kHz) is connected to XIN, then the device switches on the external clock. Else, XIN input is not considered. A
higher frequency on XIN speeds up the programmer handshake.
20.2.4 Programmer Handsh ak in g
An handshake is defined for read and write operations. When the device is ready to start a new operation (RDY signal
set), the programmer starts the handshake by clearing the NCMD signal. The handshaking is achieved once NCMD
signal is high and RDY is high.
20.2.4.1 Write Handshaking
For details on the write handshaking sequence, refer to Figure 20-2and Table 20-4.
0x0042 EWPL Erase Page and Write Page then Lock
0x0013 EA Erase All
0x0014 SLB Set Lock Bit
0x0024 CLB Clear Lock Bit
0x0015 GLB Get Lock Bit
0x0034 SGPB Set General Purpose NVM bit
0x0044 CGPB Clear General Purpose NVM bit
0x0025 GGPB Get General Purpose NVM bit
0x0054 SSE Set Security Bit
0x0035 GSE Get Security Bit
0x001F WRAM Write Memory
0x0016 SEFC S elect EFC Controller(1)
0x001E GVE Get Version
Table 20-3. Command Bit Coding (Continued)
DATA[15:0] Symbol Command Executed
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Figure 20-2. Parallel Programming Timing, Write Sequence
20.2.4.2 Read Handshaking
For details on the read handshaking sequence, refer to Figure 20-3 and Table 20-5.
Figure 20-3. Parallel Programming Timing, Read Sequence
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
1
2
3
4
5
Table 20-4. Wr ite Handshake
Step Programmer Action Device Action Data I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latches MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Releases MODE and DATA signals E xecutes command and polls NCMD high Input
5 Sets NCMD signal Executes command and polls NCMD high Input
6 Waits for RDY high Sets RDY Input
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
1
2
3
4
5
6
7
9
8
ADDR
Adress IN Z Data OUT
10
11
XIN
12
13
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20.2.5 Device Operations
Several commands on the Flash memory are available. These commands are summarized in Table 20-3 on page 114.
Each command is driven by the programmer through the parallel interface running several read/write handshaking
sequences.
When a new command is executed, the previous one is automatically achieved. Thus, chaining a read command after a
write automatically flushes the load buffer in the Flash.
20.2.5.1 Flash Read Command
This command is used to read the contents of the Flash memory. The read command can start at any valid address in
the memory plane and is optimized for consecutive reads. Read handshaking can be chained; an internal address buffer
is automatically increased.
Table 20-5. Read Handshake
Step Programmer Action Device Action DATA I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latch MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Set s DATA signal in tristate Wait s for NOE Low Input
5 Clears NOE signal Tristate
6 Waits for NVALID low Sets DATA bus in output mode and outputs
the flash contents. Output
7 Clears NVALID signal Output
8 Reads value on DATA Bus Wait s for NOE high Output
9 Set s NOE signal Output
10 Wait s for NVALID high Sets DATA bus in input mode X
11 Sets DATA in output mode Sets NVALID signal Input
12 Sets NCMD signal Waits for NCMD high Input
13 Wait s for RDY high Sets RDY signal Input
Table 20-6 . Read Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE READ
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Read handshaking DATA *Memory Address++
5 Read handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 Read handshaking DATA *Memory Address++
n+3 Read handshaking DATA *Memory Address++
... ... ... ...
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20.2.5.2 Flash Write Command
This command is used to write the Flash contents.
The Flash memory plane is organized into several pages. Data to be written are stored in a load buffer that corresponds
to a Flash memory page. The load buffer is automatically flushed to the Flash:
before access to any page other than the current one
when a new command is validated (MODE = CMDE)
The Write Page command (WP) is optimized for consecutive writes. Write handshaking can be chained; an internal
address buffer is automatically increased.
The Flash command Write Page and Lock (WPL) is equivalent to the Flash Write Command. However, the lock bit is
automatically set at the end of the Flash write operation. As a lock region is composed of several pages, the programmer
writes to the first pages of the lock region using Flash write commands and writes to the last page of the lock region using
a Flash write and lock command.
The Flash command Erase Page and Write (EWP) is equivalent to the Flash Write Command. However, before
programming the load buffer, the page is erased.
The Flash command Erase Page and Write the Lock (EWPL) combines EWP and WPL commands.
20.2.5.3 Flash Full Erase Command
This command is used to erase the Flash memory planes.
All lock regions must be unlocked before the Full Erase command by using the CLB command. Otherwise, the erase
command is aborted and no page is erased.
20.2.5.4 Flash Lock Commands
Lock bits can be set using WPL or EWPL commands. They can also be set by using the Set Lock command (SLB). With
this command, several lock bits can be activated. A Bit Mask is provided as argument to the command. When bit 0 of the
bit mask is set, then the first lock bit is activated.
Table 20-8. Write Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE WP or WPL or EWP or EWPL
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Write handshaking DATA *Memory Address++
5 Write handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 W rite handshaking DATA *Memory Address++
n+3 W rite handshaking DATA *Memory Address++
... ... ... ...
Table 20-9. Full Erase Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE EA
2 Write handshaking DATA 0
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In the same way, the Clear Lock command (CLB) is used to clear lock bits. All the lock bits are also cleared by the EA
command.
Lock bits can be read using Get Lock Bit command (GLB). The nth lock bit is active when the bit n of the bit mask is set..
20.2.5.5 Flash General-purpose NVM Commands
General-purpose NVM bits (GP NVM bits) can be set using the Set GPNVM command (SGPB). This command also
activates GP NVM bits. A bit mask is provided as argument to the command. When bit 0 of the bit mask is set, then the
first GP NVM bit is activated.
In the same way, the Clear GPNVM command (CGPB) is used to clear general-purpose NVM bits. All the general-
purpose NVM bits are also cleared by the EA command. The general-purpose NVM bit is deactivated when the
corresponding bit in the pattern value is set to 1.
General-purpose NVM bits can be read using the Get GPNVM Bit command (GGPB). The nth GP NVM bit is active when
bit n of the bit mask is set..
20.2.5.6 Flash Security Bit Command
A security bit can be set using the Set Security Bit command (SSE). Once the security bit is active, the Fast Flash
programming is disabled. No other command can be run. An event on the Erase pin can erase the security bit once the
contents of the Flash have been erased.
Table 20-10. Set and Clear Lock Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SLB or CLB
2 Write handshaking DATA Bit Mask
Table 20-11. Get Lock Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GLB
2 Read handshakin g DATA Lock Bit Mask Status
0 = Lock bit is cleared
1 = Lock bit is set
Table 20-12. Set/Clear GP NVM Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SGPB or CGPB
2 Write handshaking DATA GP NVM bit pattern value
Table 20-13. Get GP NVM Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GGPB
2 Read handshakin g DATA GP NVM Bit Mask Status
0 = GP NVM bit is cleared
1 = GP NVM bit is set
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The AT91SAM7X512 security bit is controlled by the EFC0. To use the Set Security Bit command, the EFC0 must be
selected using the Select EFC command
Once the security bit is set, it is not possible to access FFPI. The only way to erase the security bit is to erase the Flash.
In order to erase the Flash, the user must perform the following:
Power-off the chip
Power-on the chip with TST = 0
Assert Erase during a period of more than 220 ms
Power-off the chip
Then it is possible to return to FFPI mode and check that Flash is erased.
20.2.5.7 AT91SAM7X512 Select EFC Command
The commands WPx, EA, xLB, xFB are executed using the current EFC controller. The default EFC controller is EFC0.
The Select EFC command (SEFC) allows selection of the current EFC controller.
20.2.5.8 Memory Write Command
This command is used to perform a write access to any memory location.
The Memory Write command (WRAM) is optimized for consecutive writes. Write handshaking can be chained; an
internal address buffer is automatically increased.
Table 20-14. Set Security Bit Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SSE
2 Write handshaking DATA 0
Table 20-15. Select EFC Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SEFC
2 Write handshaking DATA 0 = Select EFC0
1 = Select EFC1
Table 20-16. Write Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE WRAM
2 Write handshaking ADDR0 Memory Address LSB
3 Write handshaking ADDR1 Memory Address
4 Write handshaking DATA *Memory Address++
5 Write handshaking DATA *Memory Address++
... ... ... ...
n Write handshaking ADDR0 Memory Address LSB
n+1 Write handshaking ADDR1 Memory Address
n+2 W rite handshaking DATA *Memory Address++
n+3 W rite handshaking DATA *Memory Address++
... ... ... ...
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20.2.5.9 Get Version Command
The Get Version (GVE) command retrieves the version of the FFPI interface.
Table 20-17. Get Version Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE GVE
2 Write handshaking DATA Version
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20.3 Serial Fast Flash Programming
The Serial Fast Flash programming interface is based on IEEE Std. 1149.1 “Standard Test Access Port and Boundary-
Scan Architecture”. Refer to this standard for an explanation of terms used in this chapter and for a description of the
TAP controller states.
In this mode, data read/written from/to the embedded Flash of the device are transmitted through the JTAG interface of
the device.
20.3.1 Device Configuration
In Serial Fast Flash Programming Mode, the device is in a specific test mode.Only a certain set of pins is significant, the
rest of the PIOs are used as inputs with a pull-up. The crystal oscillator is in bypass mode. Other pins must be left
unconnected.
Figure 20-4. Serial Programing
TDI
TDO
TMS
TCK
XIN
TST
VDDIO PGMEN0
PGMEN1
0-50MHz
VDDIO
VDDCORE
VDDIO
VDDPLL
VDDFLASH
GND
VDDIO
Table 20-18. Signal Description List
Signal Name Function Type Active
Level Comments
Power
VDDFLASH Flash Power Supply Power
VDDIO I/O Lines Power Supply Power
VDDCORE Core Power Supply Power
VDDPLL PLL Power Supply Power
GND Ground Ground
Clocks
XIN
Main Clock Input.
This input can be tied to GND. In this
case, the device is clocked by the internal
RC oscillator.
Input 32 kHz to 50 MHz
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20.3.2 Entering Serial Programming Mode
The following algorithm puts the device in Serial Programming Mode:
Apply GND, VDDIO, VDDCORE, VDDFLASH and VDDPLL.
Apply XIN clock within TPOR_RESET + 32(TSCLK) if an external clock is available.
Wait for TPOR_RESET.
Reset the TAP controller clocking 5 TCK pulses with TMS set.
Shift 0x2 into the IR register (IR is 4 bits long, LSB first) without going through the Run-Test-Idle state.
Shift 0x2 into the DR register (DR is 4 bits long, LSB first) without going through the Run-Test-Idle state.
Shift 0xC into the IR register (IR is 4 bits long, LSB first) without going through the Run-Test-Idle state.
Note: After reset, the device is clocked by the internal RC oscillator . Before clearing RDY signal, if an external clock ( >
32 kHz) is connected to XIN, then the device will switch on the external clock. Else, XIN input is not considered .
An higher frequency on XIN speeds up the programmer handshake.
20.3.3 Read/Write Handshake
The read/write handshake is done by carrying out read/write operations on two registers of the device that are accessible
through the JTAG:
Debug Comms Control Register: DCCR
Debug Comms Data Register: DCDR
Access to these registers is done through the TAP 38-bit DR register comprising a 32-bit data field, a 5-bit address field
and a read/write bit. The data to be written is scanned into the 32-bit data field with the address of the register to the 5-bit
Test
TST Test Mode Select Input High Must be connected to VDDIO.
PGMEN0 Test Mode Select Input High Must be connected to VDDIO
PGMEN1 Test Mode Select Input High Must be connected to VDDIO
JTAG
TCK JTAG TCK Input - Pulled-up input at reset
TDI JTAG Test Data In Input - Pulled-up input at reset
TDO JTAG Test Data Out Output -
TMS JTAG Test Mode Select Input - Pulled-up input at reset
Table 20-18. Signal Description List (Continued)
Signal Name Function Type Active
Level Comments
Table 20-19. Reset TAP Controller and Go to Select-DR-Scan
TDI TMS TAP Controller State
X1
X1
X1
X1
X 1 Test-Logic Reset
X 0 Run-Test/Idle
Xt 1 Select-DR-Scan
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address field and 1 to the read/write bit. A register is read by scanning its address into the address field and 0 into the
read/write bit, going through the UPDATE-DR TAP state, then scanning out the data.
Refer to the ARM7TDMI reference manuel for more information on Comm channel operations.
Figure 20-5. TAP 8-bit DR Register
A read or write takes place when the TAP controller enters UPDATE-DR state. Refer to the IEEE 1149.1 for more details
on JTAG operations.
The address of the Debug Comms Control Register is 0x04.
The address of the Debug Comms Data Register is 0x05.
The Debug Comms Control Register is read-only and allows synchronized handshaking between the processor
and the debugger.
Bit 1 (W): Denotes whether the programmer can read a data through the Debug Comms Data Register. If
the device is busy W = 0, then the programmer must poll until W = 1.
Bit 0 (R): Denotes whether the programmer can send data from the Debug Comms Data Register. If R = 1,
data previously placed there through the scan chain has not been collected by the device and so the
programmer must wait.
The write handshake is done by polling the Debug Comms Control Register until the R bit is cleared. Once cleared, data
can be written to the Debug Comms Data Register.
The read handshake is done by polling the Debug Comms Control Register until the W bit is set. Once set, data can be
read in the Debug Comms Data Register.
20.3.4 Device Operations
Several commands on the Flash memory are available. These commands are summarized in Table 20-3 on page 114.
Commands are run by the programmer through the serial interface that is reading and writing the Debug Comms
Registers.
20.3.4.1 Flash Read Command
This command is used to read the Flash contents. The memory map is accessible through this command. Memory is
seen as an array of words (32-bit wide). The read command can start at any valid address in the memory plane. This
address must be word-aligned. The address is automatically incremented.
TDI TDO4 0r/w Address 31 Data 0
Address
Decoder
Debug Comms Control Register
Debug Comms Data Register
32
5
Table 20-20. Read Command
Read/Write DR Data
Write (Number of Words to Read) << 16 | READ
Write Address
Read Memory [address]
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20.3.4.2 Flash Write Command
This command is used to write the Flash contents. The address transmitted must be a valid Flash address in the memory
plane.
The Flash memory plane is organized into several pages. Data to be written is stored in a load buffer that corresponds to
a Flash memory page. The load buffer is automatically flushed to the Flash:
before access to any page than the current one
at the end of the number of words transmitted
The Write Page command (WP) is optimized for consecutive writes. Write handshaking can be chained; an internal
address buffer is automatically increased.
Flash Write Page and Lock command (WPL) is equivalent to the Flash Write Command. However, the lock bit is
automatically set at the end of the Flash write operation. As a lock region is composed of several pages, the programmer
writes to the first pages of the lock region using Flash write commands and writes to the last page of the lock region using
a Flash write and lock command.
Flash Erase Page and Write command (EWP) is equivalent to the Flash Write Command. However, before
programming the load buffer, the page is erased.
Flash Erase Page and Write the Lock command (EWPL) combines EWP and WPL commands.
20.3.4.3 Flash Full Erase Command
This command is used to erase the Flash memory planes.
All lock bits must be deactivated before using the Full Erase command. This can be done by using the CLB command.
20.3.4.4 Flash Lock Commands
Lock bits can be set using WPL or EWPL commands. They can also be set by using the Set Lock command (SLB). With
this command, several lock bits can be activated at the same time. Bit 0 of Bit Mask corresponds to the first lock bit and
so on.
Read Memory [address+4]
... ...
Read Memory [address+(Number of Words to Read - 1)* 4]
Table 20-20. Read Command (Continued)
Read/Write DR Data
Table 20-21. Write Command
Read/Write DR Data
Write (Number of Words to Write) << 16 | (WP or WPL or EWP or EWPL)
Write Address
Write Memory [address]
Write Memory [address+4]
Write Memory [address+8]
Writ e Memory [add re ss+(Number of Words to Wr i te - 1)* 4]
Table 20-22. Full Erase Command
Read/Write DR Data
Write EA
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In the same way, the Clear Lock command (CLB) is used to clear lock bits. All the lock bits can also be cleared by the
EA command.
Lock bits can be read using Get Lock Bit command (GLB). When a bit set in the Bit Mask is returned, then the
corresponding lock bit is active.
20.3.4.5 Flash General-purpose NVM Commands
General-purpose NVM bits (GP NVM) can be set with the Set GPNVM command (SGPB). Using this command, several
GP NVM bits can be activated at the same time. Bit 0 of Bit Mask corresponds to the first GPNVM bit and so on.
In the same way, the Clear GPNVM command (CGPB) is used to clear GP NVM bits. All the general-purpose NVM bits
are also cleared by the EA command.
GP NVM bits can be read using Get GPNVM Bit command (GGPB). When a bit set in the Bit Mask is returned , then the
corresponding GPNVM bit is set.
20.3.4.6 Flash Security Bit Command
Security bits can be set using Set Security Bit command (SSE). Once the security bit is active, the Fast Flash
programming is disabled. No other command can be run. Only an event on the Erase pin can erase the security bit once
the contents of the Flash have been erased.
The AT91SAM7X512 security bit is controlled by the EFC0. To use the Set Security Bit command, the EFC0 must be
selected using the Select EFC command.
Once the security bit is set, it is not possible to access FFPI. The only way to erase the security bit is to erase the Flash.
In order to erase the Flash, the user must perform the following:
Power-off the chip
Power-on the chip with TST = 0
Table 20-23. Set and Clear Lock Bit Command
Read/Write DR Data
Write SLB or CLB
Write Bit Mask
Table 20-24. Get Lock Bit Command
Read/Write DR Data
Write GLB
Read Bit Mask
Table 20-25. Set and Clear General-purpose NVM Bit Command
Read/Write DR Data
Write SGPB or CGPB
Write Bit Mas k
Table 20-26. Get General-purpose NVM Bit Command
Read/Write DR Data
Write GGPB
Read Bit Mask
Table 20-27. Set Security Bit Command
Read/Write DR Data
Write SSE
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Assert Erase during a period of more than 220 ms
Power-off the chip
Then it is possible to return to FFPI mode and check that Flash is erased.
20.3.4.7 AT91SAM7X512 Select EFC Command
The commands WPx, EA, xLB, xFB are executed using the current EFC controller. The default EFC controller is EFC0.
The Select EFC command (SEFC) allows selection of the current EFC controller.
20.3.4.8 Memory Write Command
This command is used to perform a write access to any memory location.
The Memory Write command (WRAM) is optimized for consecutive writes. An internal address buffer is automatically
increased.
20.3.4.9 Get Version Command
The Get Version (GVE) command retrieves the version of the FFPI interface.
Table 20-28. Select EFC Command
Step Handshake Sequence MODE[3:0] DATA[15:0]
1 Write handshaking CMDE SEFC
2 Write handshaking DATA 0 = Select EFC0
1 = Select EFC1
Table 20-29. Write Command
Read/Write DR Data
Write (Number of Words to Write) << 16 | (WRAM)
Write Address
Write Memory [address]
Write Memory [address+4]
Write Memory [address+8]
Writ e Memory [add re ss+(Number of Words to Wr i te - 1)* 4]
Table 20-30. Get Version Command
Read/Write DR Data
Write GVE
Read Version
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21. AT91SAM Boot Program
21.1 Overview
The Boot Program integrates different programs permitting download and/or upload into the different memories of the
product.
First, it initializes the Debug Unit serial port (DBGU) and the USB Device Port.
SAM-BA Boot is then executed. It waits for transactions either on the USB device, or on the DBGU serial port.
21.2 Flow Diagram
The Boot Program implements the algorithm in Figure 21-1.
Figure 21-1. Boot Program Algorith m Flow Diagram
21.3 Device Initialization
Initialization follows the steps described below:
1. FIQ initialization
1. Stack setup for ARM supervisor mode
2. Setup the Embedded Flash Controller
3. External Clock detection
4. Main oscillator frequency detection if no external clock detected
5. Switch Master Clock on Main Oscillator
6. Copy code into SRAM
7. C variable initialization
8. PLL setup: PLL is initialized to generate a 48 MHz clock necessary to use the USB Device
9. Disable of the Watchdog and enable of the user reset
10. Initialization of the USB Device Port
11. Jump to SAM-BA Boot sequence (see “SAM-BA Boot” on page 129)
Device
Setup
AutoBaudrate
Sequence Successful ?
Run SAM-BA Boot Run SAM-BA Boot
USB Enumeration
Successful ?
Yes Yes
No
No
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21.4 SAM-BA Boot
The SAM-BA boot principle is to:
Check if USB Device enumeration has occurred
Check if the AutoBaudrate sequence has succeeded (see Figure 21-2)
Figure 21-2. AutoBaudrate Flow Diagram
Once the communication interface is identified, the application runs in an infinite loop waiting for different
commands as in Table 21-1.
Table 21-1. Commands Available through the SAM-BA Boot
Command Action Argument(s) Example
Owrite a byte Address, Value# O200001,CA#
oread a byte Address,# o200001,#
Hwrite a half word Address, Value# H200002,CAFE#
hread a half word Address,# h200002,#
Wwrite a word Address, Value# W200000,CAFEDECA#
wread a word Address,# w200000,#
Ssend a file Address,# S200000,#
Rreceive a file Address, NbOfBytes# R200000,1234#
Ggo Address# G200200#
Vdisplay version No argument V#
Device
Setup
Character '0x80'
received ? No
Yes
Character '0x80'
received ? No
Yes
Character '#'
received ?
Yes
Run SAM-BA Boot
Send Character '>'
No
1st measurement
2nd measurement
Test Communication
UART operational
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Write commands: Write a byte (O), a halfword (H) or a word (W) to the target.
Address: Address in hexadecimal.
Value: Byte, halfword or word to write in hexadecimal.
Output: ‘>’.
Read commands: Read a byte (o), a halfword (h) or a word (w) from the target.
Address: Address in hexadecimal
Output: The byte, halfword or word read in hexadecimal following by ‘>’
Send a file (S): Send a file to a specified address
Address: Address in hexadecimal
Output: ‘>’.
Note: There is a time-out on this command which is reached when the prompt ‘>’ appears before the end of the com-
mand execution.
Receive a file (R): Receive data into a file from a specified address
Address: Address in hexadecimal
NbOfBytes: Number of bytes in hexadecimal to receive
Output: ‘>’
Go (G): Jump to a specified address and execute the code
Address: Address to jump in hexadecimal
Output: ‘>’
Get Version (V): Return the SAM-BA boot version
Output: ‘>’
21.4.1 DBGU Serial Port
Communication is performed through the DBGU serial port initialized to 115200 Baud, 8, n, 1.
The Send and Receive File commands use the Xmodem protocol to communicate. Any terminal performing this protocol
can be used to send the application file to the target. The size of the binary file to send depends on the SRAM size
embedded in the product. In all cases, the size of the binary file must be lo wer than the SRAM size because the Xmodem
protocol requires some SRAM memory to work.
21.4.2 Xmodem Protocol
The Xmodem protocol supported is the 128-byte length block. This protocol uses a two-character CRC-16 to guarantee
detection of a maximum bit error.
Xmodem protocol with CRC is accurate provided both sender and receiver report successful transmission. Each block of
the transfer looks like:
<SOH><blk #><255-blk #><--128 data bytes--><checksum> in which:
<SOH> = 01 hex
<blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not to 01)
<255-blk #> = 1’s complement of the blk#.
<checksum> = 2 bytes CRC16
Figure 21-3 shows a transmission using this protocol.
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Figure 21-3. X mod em Transfer Example
21.4.3 USB Device Port
A 48 MHz USB clock is necessary to use the USB Device port. It has been programmed earlier in the device initialization
procedure with PLLB configuration.
The device uses the USB communication device class (CDC) drivers to take advantage of the installed PC RS-232
software to talk over the USB. The CDC class is implemented in all releases of Windows®, from Windows 98SE to
Windows XP®. The CDC document, available at www.usb.org, describes a way to implement devices such as ISDN
modems and virtual COM ports.
The Vendor ID is Atmel’s vendor ID 0x03EB. The product ID is 0x6124. These references are used by the host operating
system to mount the correct driver. On Windows systems, the INF files contain the correspondence between vendor ID
and product ID.
Atmel provides an INF example to see the device as a new serial port and also provides another custom driver used by
the SAM-BA application: atm6124.sys. Refer to the document “USB Basic Application”, literature number 6123, for more
details.
21.4.3.1 Enumeration Process
The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the device
through the control endpoint. The device handles standard requests as defined in the USB Specification.
Host Device
SOH 01 FE Data[128] CRC CRC
C
ACK
SOH 02 FD Data[128] CRC CRC
ACK
SOH 03 FC Data[100] CRC CRC
ACK
EOT
ACK
Table 21-2. Handled Standard Requests
Request Definition
GET_DESCRIPTOR Returns the current device configuration value.
SET_ADDRESS Sets the device address for all future device access.
SET_CONFIGURATION Sets the device configuration.
GET_CONFIGURATION Returns the current device configuration value.
GET_STATUS Return s status for the specified reci pient.
SET_FEATURE Used to set or enable a specific feature.
CLEAR_FEATURE Used to clear or disable a specific feature.
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The device also handles some class requests defined in the CDC class.
Unhandled requests are STALLed.
21.4.3.2 Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process. Endpoint 1 is a 64-byte
Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN en dpoi nt. SAM-BA Boot commands are sent by the host through
the endpoint 1. If required, the message is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the response.
Table 21-3. Handled Class Reque sts
Request Definition
SET_LINE_CODING Configures DTE rate, stop bits, parity and number of
character bits.
GET_LINE_CODING Requests current DTE rate, stop bits, parity and number of
character bits.
SET_CONTROL_LINE_STATE RS-232 signal used to tell the DCE device the DTE device
is now present.
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21.5 Hardware and Software Constraints
SAM-BA boot copies itself in the SRAM and uses a block of internal SRAM for variables and stacks. The
remaining available size for the user code is 122880 bytes for SAM7x512, 57344 bytes f or SAM7 X256 and 24576
bytes for SAM7X128.
USB requirements:
pull-up on DDP
18.432 MHz Quartz
Table 21-4. User Area Addresses
Device Start Address End Address Size (bytes)
SAM7X512 0x202000 0x220000 122880
SAM7X256 0x202000 0x210000 57344
SAM7X128 0x202000 0x208000 24576
Table 21-5 . Pins Driven du ring Boo t Progr am Execution
Peripheral Pin PIO Line
DBGU DRXD PA27
DBGU DTXD PA28
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22. Peripheral DMA Controller (PDC)
22.1 Overview
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals such as the UART, USART,
SSC, SPI, MCI and the on- and off-chip memories. Using the Peripheral DMA Controller avoids processor intervention
and removes the processor interrupt-handling overhead. This significantly reduces the number of clock cycles required
for a data transfer and, as a result, improves the performance of the microcontroller and makes it more power efficient.
The PDC channels are implemented in pairs, each pair being dedicated to a particular peripheral. One channel in the pair
is dedicated to the receiving channel and one to the transmitting channel of each UART, USART, SSC and SPI.
The user interface of a PDC channel is integrated in the memory space of each peripheral. It contains:
A 32-bit memory pointer register
A 16-bit transfer count register
A 32-bit register for next memory pointer
A 16-bit register for next transfer count
The peripheral triggers PDC transfers using transmit and receive signals. When the programmed data is transferred, an
end of transfer interrupt is generated by the corresponding peripheral.
22.2 Block Diagram
Figure 22-1. Block Diagram
22.3 Functional Description
22.3.1 Configuration
The PDC channels user interface enables the user to configure and control the data transfers for each channel. The user
interface of a PDC channel is integrated into the user interface of the peripheral (offset 0x100), which it is related to.
Per peripheral, it contains four 32-bit Pointer Registers (RPR, RNPR, TPR, and TNPR) and four 16-bit Counter Registers
(RCR, RNCR, TCR, and TNCR).
Control
PDC Channel 0
PDC Channel 1
THR
RHR
Control Status & Control
Peripheral Peripheral DMA Controller
Memory
Controller
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The size of the buffer (number of transfers) is configured in an internal 16-bit transfer counter register, and it is possible,
at any moment, to read the number of transfers left for each channel.
The memory base address is configured in a 32-bit memory pointer by defining the location of the first address to access
in the memory. It is possible, at any moment, to read the location in memory of the next transfer and the number of
remaining transfers. The PDC has dedicated status registers which indicate if the transfer is enabled or disabled for each
channel. The status for each channel is located in the peripheral status register. Transfers can be enabled and/or
disabled by setting TXTEN/TXTDIS and RXTEN/RXTDIS in PDC Transfer Control Register. These control bits enable
reading the pointer and counter registers safely without any risk of their changing between both reads.
The PDC sends status flags to the peripheral visible in its status-register (ENDRX, ENDTX, RXBUFF, and TXBUFE).
ENDRX flag is set when the PERIPH_RCR register reaches zero.
RXBUFF flag is set when both PERIPH_RCR and PERIPH_RNCR reach zero.
ENDTX flag is set when the PERIPH_TCR register reaches zero.
TXBUFE flag is set when both PERIPH_TCR and PERIPH_TNCR reach zero.
These status flags are described in the peripheral status register.
22.3.2 Memory Pointers
Each peripheral is connected to the PDC by a receiver data channel and a transmitter data channel. Each channel has
an internal 32-bit memory pointer. Each memory pointer points to a location anywhere in the memory space (on-chip
memory or external bus interface memory).
Depending on the type of transfer (byte, half-word or word), the memory pointer is incremented by 1, 2 or 4, respectively
for peripheral transfers.
If a memory pointer is reprogrammed while the PDC is in operation, the transfer address is changed, and the PDC
performs transfers using the new address.
22.3.3 Transfer Counters
There is one internal 16-bit transfer counter for each channel used to count the size of the block already transferred by its
associated channel. These counters are decremented after each data transfer. When the counter reaches zero, the
transfer is complete and the PDC stops transferring data.
If the Next Counter Register is equal to zero, the PDC disables the trigger while activating the related peripheral end flag.
If the counter is reprogrammed while the PDC is operating, the number of transfers is updated and the PDC counts
transfers from the new value.
Programming the Next Counter/Pointer registers chains the buffers. The counters are decremented after each data
transfer as stated above, but when the transfer counter reaches zero, the values of the Next Counter/Pointer are loaded
into the Counter/Pointer registers in order to re-enable the triggers.
For each channel, two status bits indicate the end of the current buffer (ENDRX, ENTX) and the end of both current and
next buffer (RXBUFF, TXBUFE). These bits are directly mapped to the peripheral status register and can trigger an
interrupt request to the AIC.
The peripheral end flag is automatically cleared when one of the counte r-registers (Counter or Next Counter Register) is
written.
Note: When the Next Counter Register is loaded into the Counter Register, it is set to zero.
22.3.4 Data Transfers
The peripheral triggers PDC transfers using transmit (TXRDY) and receive (RXRDY) signals.
When the peripheral receives an external character, it sends a Receive Ready signal to the PDC which then requests
access to the system bus. When access is granted, the PDC starts a read of the peripheral Receive Holding Register
(RHR) and then triggers a write in the memory.
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After each transfer, the relevant PDC memory pointer is incremented and the number of transfers left is decremented.
When the memory block size is reached, a signal is sent to the peripheral and the transfer stops.
The same procedure is followed, in reverse, for transmit transfers.
22.3.5 Priority of PDC Transfer Requests
The Peripheral DMA Controller handles transfer requests from the channel according to priorities fixed for each
product.These priorities are defined in the product datasheet.
If simultaneous requests of the same type (receiver or transmitter) occur on identical peripherals, the priority is
determined by the numbering of the peripherals.
If transfer requests are not simultaneous, they are treated in the order they occurred. Requests from the receivers are
handled first and then followed by transmitter requests.
22.4 Peripheral DMA Controller (PDC) User Interface
Note: 1. PERIPH: Ten registers are mapped in the peripheral memory space at the same offset. These can be defined by the
user according to the function and the peripheral desired (DBGU, USART, SSC, SPI, MCI, etc.).
Table 22-1. Regist er Mapping
Offset Register Name A ccess Reset
0x100 Receive Pointer Register PERIPH(1)_RPR Read-write 0x0
0x104 Receive Counter Register PERIPH_RCR Read-write 0x0
0x108 Transmit Pointer Register PERIPH_TPR Read-write 0x0
0x10C Transmit Counter Register PERIPH_TCR Read-write 0x0
0x110 Receive Next Pointer Register PERIPH_RNPR Read-write 0x0
0x114 Receive Next Counter Register PERIPH_RNCR Read-write 0x0
0x118 Transmit Next Pointer Register PERIPH_TNPR Read-write 0x0
0x11C Transmit Next Counter Register PERIPH_TNCR Read-write 0x 0
0x120 PDC Transfer Control Register PERIPH_PTCR Write-only -
0x124 PDC Transfer Status Register PERIPH_PTSR Read-only 0x0
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22.4.1 PDC Receive Pointer Register
Register Name: PERIPH_RPR
Access Type: Read-write
• RXPTR: Receive Pointer Address
Address of the next receive transfer.
22.4.2 PDC Receive Counter Register
Register Name: PERIPH_RCR
Access Type: Read-write
• RXCTR: Receive Counter Value
Number of receive transfers to be performed.
31 30 29 28 27 26 25 24
RXPTR
23 22 21 20 19 18 17 16
RXPTR
15 14 13 12 11 10 9 8
RXPTR
76543210
RXPTR
31 30 29 28 27 26 25 24
--
23 22 21 20 19 18 17 16
--
15 14 13 12 11 10 9 8
RXCTR
76543210
RXCTR
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22.4.3 PDC Tran smi t Poi n te r Re gi st er
Register Name: PERIPH_TPR
Access Type: Read-write
• TXPTR: Transmit Pointer Address
Address of the transmit buffer.
22.4.4 PDC Transmit Counter Register
Register Name: PERIPH_TCR
Access Type: Read-write
• TXCTR: Transmit Counter Value
TXCTR is the size of the transmit transfer to be performed. At zero, the peripheral DMA transfer is stopped.
31 30 29 28 27 26 25 24
TXPTR
23 22 21 20 19 18 17 16
TXPTR
15 14 13 12 11 10 9 8
TXPTR
76543210
TXPTR
31 30 29 28 27 26 25 24
--
23 22 21 20 19 18 17 16
--
15 14 13 12 11 10 9 8
TXCTR
76543210
TXCTR
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22.4.5 PDC Receive Next Pointer Register
Register Name: PERIPH_RNPR
Access Type: Read-write
• RXNPTR: Receive Next Pointer Address
RXNPTR is the address of the next buffer to fill with received data when the current buffer is full.
22.4.6 PDC Receive Next Counter Register
Register Name: PERIPH_RNCR
Access Type: Read-write
• RXNCR: Receive Next Counter Value
RXNCR is the size of the next buffer to receive.
31 30 29 28 27 26 25 24
RXNPTR
23 22 21 20 19 18 17 16
RXNPTR
15 14 13 12 11 10 9 8
RXNPTR
76543210
RXNPTR
31 30 29 28 27 26 25 24
--
23 22 21 20 19 18 17 16
--
15 14 13 12 11 10 9 8
RXNCR
76543210
RXNCR
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22.4.7 PDC Transmit Next Pointer Register
Register Name: PERIPH_TNPR
Access Type: Read-write
• TXNPTR: Transmit Next Pointer Address
TXNPTR is the address of the next buffer to transmit when the current buffer is empty.
22.4.8 PDC Transmit Next Counter Register
Register Name: PERIPH_TNCR
Access Type: Read-write
• TXNCR: Transmit Next Counter Value
TXNCR is the size of the next buffer to transmit.
31 30 29 28 27 26 25 24
TXNPTR
23 22 21 20 19 18 17 16
TXNPTR
15 14 13 12 11 10 9 8
TXNPTR
76543210
TXNPTR
31 30 29 28 27 26 25 24
--
23 22 21 20 19 18 17 16
--
15 14 13 12 11 10 9 8
TXNCR
76543210
TXNCR
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22.4.9 PDC Transfer Control Register
Register Name: PERIPH_PTCR
Access Type: Write-only
• RXTEN: Receiver Transfer Enable
0 = No effect.
1 = Enables the receiver PDC transfer requests if RXTDIS is not set.
• RXTDIS: Receiver Transfer Disabl e
0 = No effect.
1 = Disables the receiver PDC transfer requests.
• TXTEN: Transmitter Transfer Enable
0 = No effect.
1 = Enables the transmitter PDC transfer requests.
• TXTDIS: Transmitter Transfer Disable
0 = No effect.
1 = Disables the transmitter PDC transfer requests
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––TXTDISTXTEN
76543210
––––––RXTDISRXTEN
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22.4.10 PDC Transfer Status Register
Register Name: PERIPH_PTSR
Access Type: Read-only
• RXTEN: Receiver Transfer Enable
0 = Receiver PDC transfer requests are disabled.
1 = Receiver PDC transfer requests are enabled.
• TXTEN: Transmitter Transfer Enable
0 = Transmitter PDC transfer requests are disabled.
1 = Transmitter PDC transfer requests are enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––TXTEN
76543210
–––––––RXTEN
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23. Advanced Interrupt Controller (AIC)
23.1 Overview
The Advanced Interrupt Controller (AIC) is an 8-level priority, individually maskable, vectored interrupt controller,
providing handling of up to thirty-two interrupt sources. It is designed to substantially reduce the software and real-time
overhead in handling internal and external interrupts.
The AIC drives the nFIQ (fast interrupt request) and the nIRQ (standard interrupt request) inputs of an ARM processor.
Inputs of the AIC are either internal peripheral interrupts or external interrupts coming from the product's pins.
The 8-level Priority Controller allows the user to define the priority for each interrupt source, thus permitting higher priority
interrupts to be serviced even if a lower priority interrupt is being treated.
Internal interrupt sources can be programmed to be level sensitive or edge triggered. External interrupt sources can be
programmed to be positive-edge or negative-edge triggered or high-level or low-level sensitive.
The fast forcing feature redirects any internal or external interrupt source to provide a fast interrupt rather than a normal
interrupt.
23.2 Block Diagram
Figure 23-1. Block Diagram
AIC
APB
ARM
Processor
FIQ
IRQ0-IRQn
Embedded
PeripheralEE
Peripheral
Embedded
Peripheral
Embedded
Up to
Thirty-two
Sources nFIQ
nIRQ
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23.3 Application Block Diagram
Figure 23-2. Description of the Applicati on Block
23.4 AIC Detailed Bl ock Diagram
Figure 23-3 . AIC Detailed Block Dia gr am
23.5 I/O Line Description
Advanced Interrupt Controller
Embedded Peripherals External Peripherals
(External Interrupts)
Standalone
Applications RTOS Drivers Hard Real Time Tasks
OS-based Applications
OS Drivers
General OS Interrupt Handler
FIQ
PIO
Controller
Advanced Interrupt Controller
IRQ0-IRQn PIOIRQ
Embedded
Peripherals
External
Source
Input
Stage
Internal
Source
Input
Stage
Fast
Forcing Interrupt
Priority
Controller
Fast
Interrupt
Controller
ARM
Processor
nFIQ
nIRQ
Power
Management
Controller
Wake UpUser Interface
APB
Processor
Clock
Table 23-1. I/O Line Description
Pin Name Pin Description Type
FIQ Fast Interrupt Input
IRQ0 - IRQn Interrupt 0 - Interrupt n Input
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23.6 Product Dependencies
23.6.1 I/O Lines
The interrupt signals FIQ and IRQ0 to IRQn are normally multiplexed through the PIO controllers. Depending on the
features of the PIO controller used in the product, the pins must be programmed in accordance with their assigned
interrupt function. This is not applicable when the PIO controller used in the product is transparent on the input path.
23.6.2 Power Management
The Advanced Interrupt Controller is continuously clocked. The Power Management Controller has no effect on the
Advanced Interrupt Controller behavior.
The assertion of the Advanced Interrupt Controller outputs, either nIRQ or nFIQ, wakes up the ARM processor while it is
in Idle Mode. The General Interrupt Mask feature enables the AIC to wake up the processor without asserting the
interrupt line of the processor, thus providing synchronization of the processor on an event.
23.6.3 Interrupt Sources
The Interrupt Source 0 is always located at FIQ. If the product does not feature an FIQ pin, the Interrupt Source 0 cannot
be used.
The Interrupt Source 1 is always located at System Interrupt. This is the result of the OR-wiring of the system peripheral
interrupt lines, such as the System Timer, the Real Time Clock, the Power Management Controller and the Memory
Controller. When a system interrupt occurs, the service routine must first distinguish the cause of the interrupt. This is
performed by reading successively the status registers of the above mentioned system peripherals.
The interrupt sources 2 to 31 can either be connected to the interrupt outputs of an embedded user peripheral or to
external interrupt lines. The external interrupt lines can be connected directly, or through the PIO Controller.
The PIO Controllers are considered as user peripherals in the scope of interrupt handling. Accordingly, the PIO
Controller interrupt lines are connected to the Interrupt Sources 2 to 31.
The peripheral identification defined at the product level corresponds to the interrupt source number (as well as the bit
number controlling the clock of the peripheral). Consequently, to simplify the description of the functional o perations and
the user interface, the interrupt sources are named FIQ, SYS, and PID2 to PID31.
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23.7 Functional Description
23.7.1 Interrupt Source Control
23.7.1.1 Interrupt Source Mode
The Advanced Interrupt Controller independently programs each interrupt source. The SRCTYPE field of the
corresponding AIC_SMR (Source Mode Register) selects the interrupt condition of each source.
The internal interrupt sources wired on the interrupt outputs of the embedded peripherals can be programmed either in
level-sensitive mode or in edge-triggered mode. The active level of the internal interrupts is not important for the user.
The external interrupt sources can be programmed either in high level-sensitive or low level-sensitive modes, or in
positive edge-triggered or negative edge-triggered modes.
23.7.1.2 Interrupt Source Enabling
Each interrupt source, including the FIQ in source 0, can be enabled or disabled by using the command registers;
AIC_IECR (Interrupt Enable Command Register) and AIC_IDCR (Interrupt Disable Command Register). This set of
registers conducts enabling or disabling in one instruction. The interrupt mask can be read in the AIC_IMR register. A
disabled interrupt does not affect servicing of other interrupts.
23.7.1.3 Interrupt Clearing and Setting
All interrupt sources programmed to be edge-triggered (including the FIQ in source 0) can be individually set or cleared
by writing respectively the AIC_ISCR and AIC_ICCR registers. Clearing or setting interrupt sources programmed in level-
sensitive mode has no effect.
The clear operation is perfunctory, as the software must perform an action to reinitialize the “memorization” circuitry
activated when the source is programmed in edge-triggered mode. However, the set operation is available for auto-test
or software debug purposes. It can also be used to execute an AIC-implementation of a software interrupt.
The AIC features an automatic clear of the current interrupt when the AIC_IVR (Interrupt Vector Register) is read. Only
the interrupt source being detected by the AIC as the current interrupt is affected by this operation. (See “Priority
Controller” on page 149.) The automatic clear reduces the operations required by the interrupt service routine entry code
to reading the AIC_IVR. Note that the automatic interrupt clear is disabled if the interrupt source has the Fast Forcing
feature enabled as it is considered uniquely as a FIQ source. (For further details, See “Fast Forcing” on page 153.)
The automatic clear of the interrupt source 0 is performed when AIC_FVR is read.
23.7.1.4 Interrupt Status
For each interrupt, the AIC operation originates in AIC_IPR (Interrupt Pending Register) and its mask in AIC_IMR
(Interrupt Mask Register). AIC_IPR enables the actual activity of the sources, whether masked or not.
The AIC_ISR register reads the number of the current interrupt (see “Priority Controller” on page 149) and the register
AIC_CISR gives an image of the signals nIRQ and nFIQ driven on the processor.
Each status referred to above can be used to optimize the interrupt handling of the systems.
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23.7.1.5 Internal Interrupt Source Input Stage
Figure 23-4. Internal Interru pt Source Input Stage
23.7.1.6 External Interrupt Source Input Stage
Figure 23-5. External Interrupt Source Input Stage
Edge
Detector
ClearSet
Source i AIC_IPR
AIC_IMR
AIC_IECR
AIC_IDCR
AIC_ISCR
AIC_ICCR
Fast Interrupt Controller
or
Priority Controller
FF
Level/
Edge
AIC_SMRI
(SRCTYPE)
Edge
Detector
ClearSet
Pos./Neg.
AIC_ISCR
AIC_ICCR
Source i
FF
Level/
Edge
High/Low AIC_SMRi
SRCTYPE
AIC_IPR
AIC_IMR
AIC_IECR
AIC_IDCR
Fast Interrupt Controller
or
Priority Controller
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23.7.2 Interrupt Latencies
Global interrupt latencies depend on several parameters, including:
The time the software masks the interrupts.
Occurrence, either at the processor level or at the AIC level.
The execution time of the instruction in progress when the interrupt occurs.
The treatment of higher priority interrupts and the resynchronization of the hardware signals.
This section addresses only the hardware resynchronizations. It gives details of the latency times between the event on
an external interrupt leading in a valid interrupt (edge or level) or the assertion of an internal interrupt source and the
assertion of the nIRQ or nFIQ line on the processor. The resynchronization time depends on the programming of the
interrupt source and on its type (internal or external). For the standard interrupt, resynchronization times are given
assuming there is no higher priority in progress.
The PIO Controller multiplexing has no effect on the interrupt latencies of the external interrupt sources.
23.7.2.1 External Interrupt Edge Triggered Source
Figure 23-6. External Interrupt Edge Triggered Source
23.7.2.2 External Interrupt Level Sensitive Source
Figure 23-7. External Interrupt Level Sensitive Source
Maximum FIQ Latency = 4 Cycles
Maximum IRQ Latency = 4 Cycles
nFIQ
nIRQ
MCK
IRQ or FIQ
(Positive Edge)
IRQ or FIQ
(Negative Edge)
Maximum IRQ
Latency = 3 Cycles
Maximum FIQ
Latency = 3 cycles
MCK
IRQ or FIQ
(High Level)
IRQ or FIQ
(Low Level)
nIRQ
nFIQ
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23.7.2.3 Internal Interrupt Edge Triggered Source
Figure 23-8. Internal Interrupt Edge Triggered Source
23.7.2.4 Internal Interrupt Level Sensitive Source
Figure 23-9. Internal Interrupt Level Sensitive Source
23.7.3 Normal Interrupt
23.7.3.1 Priority Controller
An 8-level priority controller drives the nIRQ line of the processor, depending on the interrupt condition s occurring on the
interrupt sources 1 to 31 (except for those programmed in Fast Forcing).
Each interrupt source has a programmable priority level of 7 to 0, which is user-definable by writing the PRIOR field of
the corresponding AIC_SMR (Source Mode Register). Level 7 is the highest priority and level 0 the lowest.
As soon as an interrupt condition occurs, as defined by the SRCTYPE field of the AIC_SMR (Source Mode Register), the
nIRQ line is asserted. As a new interrupt condition might have happened on other interrupt sources since the nIRQ has
been asserted, the priority controller determines the current interrupt at the time the AIC_IVR (Interrupt Vector Register)
is read. The read of AIC_IVR is the entry point of the interrupt handling which allows the AIC to consider that the
interrupt has been taken into account by the software.
The current priority level is defined as the priority level of the current interrupt.
If several interrupt sources of equal priority are pending and enabled when the AIC_IVR is read, the interrupt with the
lowest interrupt source number is serviced first.
The nIRQ line can be asserted only if an interrupt condition occurs on an interrupt source with a higher priority. If an
interrupt condition happens (or is pending) during the interrupt treatment in progress, it is delayed until the software
indicates to the AIC the end of the current service by writing the AIC_EOICR (End of Interrupt Command Register). The
write of AIC_EOICR is the exit point of the interrupt handling.
MCK
nIRQ
Peripheral Interrupt
Becomes Active
Maximum IRQ Latency = 4.5 Cycles
MCK
nIRQ
Maximum IRQ Latency = 3.5 Cycles
Peripheral Interrupt
Becomes Active
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23.7.3.2 Interrupt Nesting
The priority controller utilizes interrupt nesting in order for the high priority interrupt to be handled during the service of
lower priority interrupts. This requires the interrupt service routines of the lower interrupts to re-enable the interrupt at the
processor level.
When an interrupt of a higher priority happens during an already occurring interrupt service routine, the nIRQ line is re-
asserted. If the interrupt is enabled at the core level, the current execution is interrupted and the new interrupt service
routine should read the AIC_IVR. At this time, the current interrupt number and its priority level are pushed into an
embedded hardware stack, so that they are saved and restored when the higher priority interrupt servicing is finished and
the AIC_EOICR is written.
The AIC is equipped with an 8-level wide hardware stack in order to support up to eight interrupt nestings pursuant to
having eight priority levels.
23.7.3.3 Interrupt Vectoring
The interrupt handler addresses corresponding to each interrupt source can be stored in the registers AIC_SVR1 to
AIC_SVR31 (Source Vector Register 1 to 31). When the processor reads AIC_IVR (Interrupt Vector Register), the value
written into AIC_SVR corresponding to the current interrupt is returned.
This feature offers a way to branch in one single instruction to the handler corresponding to the current interrupt, as
AIC_IVR is mapped at the absolute address 0xFFFF F100 and thus accessible from the ARM interrupt vector at address
0x0000 0018 through the following instruction:
LDR PC,[PC,# -&F20]
When the processor executes this instruction, it loads the read value in AIC_IVR in its program counter, thus branching
the execution on the correct interrupt handler.
This feature is often not used when the application is based on an operating system (either real time or not). Operating
systems often have a single entry point for all the interrupts and the first task performed is to discern the source of the
interrupt.
However, it is strongly recommended to port the operating system on AT91 products by supporting the interrupt
vectoring. This can be performed by defining all the AIC_SVR of the interrupt source to be handled by the operating
system at the address of its interrupt handler. When doing so, the interrupt vectoring permits a critical interrupt to transfer
the execution on a specific very fast handler and not onto the operating system’s general interrupt handler. This
facilitates the support of hard real-time tasks (input/outputs of voice/audio buffers and software peripheral handling) to be
handled efficiently and independently of the application running under an operating system.
23.7.3.4 Interrupt Handlers
This section gives an overview of the fast interrupt handling sequence when using the AIC. It is assumed that the
programmer understands the architecture of the ARM processor, and especially the processor interrupt modes and the
associated status bits.
It is assumed that:
1. The Advanced Interrupt Controller has been programmed, AIC_SVR registers are loaded with corresponding inter-
rupt service routine addresses and interrupts are enabled.
2. The instruction at the ARM interrupt exception vector address is required to work with the vectoring
LDR PC, [PC, # -&F20]
When nIRQ is asserted, if the bit “I” of CPSR is 0, the sequence is as follows:
1. The CPSR is stored in SPSR_irq, the current value of the Program Counter is loaded in the Interrupt link register
(R14_irq) and the Program Counter (R15) is loaded with 0x18. In the following cycle during fetch at address 0x1C,
the ARM core adjusts R14_irq, decrementing it by four.
2. The ARM core enters Interrupt mode, if it has not already done so.
3. When the instruction loaded at address 0x18 is executed, the program counter is loaded with the value read in
AIC_IVR. Reading the AIC_IVR has the following effects:
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Sets the current interrupt to be the pending and enabled interrupt with the highest priority. The current level
is the priority level of the current interrupt.
De-asserts the nIRQ line on the processor. Even if vectoring is not used, AIC_IVR must be read in order to
de-assert nIRQ.
Automatically clears the interrupt, if it has been programmed to be edge-triggered.
Pushes the current level and the current interrupt number on to the stack.
Returns the value written in the AIC_SVR corresponding to the current interrupt.
4. The previous step has the effect of branching to the corresponding interrupt service routine. This should start by
saving the link register (R14_irq) and SPSR_IRQ. The link register must be decremented by four when it is saved
if it is to be restored directly into the program counter at the end of the interrupt. For example, the instruction SUB
PC, LR, #4 may be used.
5. Further interrupts can then be unmasked by clearing the “I” bit in CPSR, allowing re-assertion of the nIRQ to be
taken into account by the core. This can happen if an interrupt with a higher priority than the current interrupt
occurs.
6. The interrupt handler can then proceed as required, saving the registers that will be used and restoring them at the
end. During this phase, an interrupt of higher priority than the current level will restart the sequence from step 1.
Note: If the interrupt is programmed to be level sensitive, the source of the interrupt must be cleared during this phase.
7. The “I” bit in CPSR must be set in order to mask interrupts before exiting to ensure that the interrupt is completed
in an orderly manner.
8. The End of Interrupt Command Register (AIC_EOICR) must be written in order to indicate to the AIC that the cur-
rent interrupt is finished. This causes the current level to be popped from the stack, restoring the previous current
level if one exists on the stack. If another interrupt is pending, with lower or equal priority than the old current level
but with higher priority than the new current level, the nIRQ line is re -asserted, but the interrupt sequence does not
immediately start because the “I” bit is set in the core. SPSR_irq is restored. Finally, the saved value of the link reg-
ister is restored directly into the PC. This has the effect of returning from the interrupt to whatever was being
executed before, and of loading the CPSR with the stored SPSR, masking or unmasking th e interrupts depending
on the state saved in SPSR_irq.
Note: The “I” bit in SPSR is significant. If it is set, it indicates that the ARM core was on the verge of masking an inter-
rupt when the mask instruction was interrupted. Hence, when SPSR is restored, the mask instruction is
completed (interrupt is masked).
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23.7.4 Fast Interrupt
23.7.4.1 Fast Interrupt Source
The interrupt source 0 is the only source which can raise a fast interrupt request to the processor except if fast forcing is
used. The interrupt source 0 is generally connected to a FIQ pin of the product, either directly or through a PIO
Controller.
23.7.4.2 Fast Interrupt Control
The fast interrupt logic of the AIC has no priority controller. The mode of interrupt source 0 is programmed with the
AIC_SMR0 and the field PRIOR of this register is not used even if it reads what has been written. The field SRCTYPE of
AIC_SMR0 enables programming the fast interrupt source to be positive-edge triggered or negative-edge triggered or
high-level sensitive or low-level sensitive
Writing 0x1 in the AIC_IECR (Interrupt Enable Command Register) and AIC_IDCR (Interrupt Disable Command
Register) respectively enables and disables the fast interrupt. The bit 0 of AIC_IMR (Interrupt Mask Register) indicates
whether the fast interrupt is enabled or disabled.
23.7.4.3 Fast Interrupt Vectoring
The fast interrupt handler address can be stored in AIC_SVR0 (Source Vector Register 0). The value written into this
register is returned when the processor reads AIC_FVR (Fast Vector Register). This offers a way to branch in one single
instruction to the interrupt handler, as AIC_FVR is mapped at the absolute address 0xFFFF F104 and thus accessible
from the ARM fast interrupt vector at address 0x0000 001C through the following instruction:
LDR PC,[PC,# -&F20]
When the processor executes this instruction it loads the value read in AIC_FVR in its program counter, thus branching
the execution on the fast interrupt handler. It also automatically performs the clear of the fast interrupt source if it is
programmed in edge-triggered mode.
23.7.4.4 Fast Interrupt Handlers
This section gives an overview of the fast interrupt handling sequence when using the AIC. It is assumed that the
programmer understands the architecture of the ARM processor, and especially the processor interrupt modes and
associated status bits.
Assuming that:
1. The Advanced Interrupt Controller has been programmed, AIC_SVR0 is loaded with the fast interrupt service rou-
tine address, and the interrupt source 0 is enabled.
2. The Instruction at address 0x1C (FIQ exception vector address) is required to vector the fast interrupt:
LDR PC, [PC, # -&F20]
3. The user does not need nested fast interrupts.
When nFIQ is asserted, if the bit “F” of CPSR is 0, the sequence is:
1. The CPSR is stored in SPSR_fiq, the current value of the program counter is loaded in the FIQ link register
(R14_FIQ) and the program counter (R15) is loaded with 0x1C. In the following cycle, during fetch at address
0x20, the ARM core adjusts R14_fiq, decrementing it by four.
2. The ARM core enters FIQ mode.
3. When the instruction loaded at address 0x1C is executed, the program counter is loaded with the value read in
AIC_FVR. Reading the AIC_FVR has effect of automatically clearing the fast interrupt, if it has been programmed
to be edge triggered. In this case only, it de-asserts the nFIQ line on the processor.
4. The previous step enables branching to the corresponding interrupt service routine. It is not necessary to save the
link register R14_fiq and SPSR_fiq if nested fast interrupts are not needed.
5. The Interrupt Handler can then proceed as required. It is not necessary to save registers R8 to R13 because FIQ
mode has its own dedicated registers and the user R8 to R13 are banked. The other registers, R0 to R7, must be
saved before being used, and restored at the end (before the next step). Note that if the fast interrupt is pro-
grammed to be level sensitive, the source of the interrupt must be cleared during this phase in order to de-assert
the interrupt source 0.
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6. Finally, the Link Register R14_fiq is restored into the PC after decrementing it by four (with instruction SUB PC,
LR, #4 for example). This has the effect of returning from the interrupt to whatever was being executed before,
loading the CPSR with the SPSR and masking or unmasking the fast interrupt dep ending on the state saved in the
SPSR.
Note: The “F” bit in SPSR is significant. If it is set, it indicates that the ARM core was just about to mask FIQ interrupt s
when the mask instruction was interrupted. He nce when the SPSR is restored, the interrupted instruction is com-
pleted (FIQ is masked).
Another way to handle the fast interrupt is to map the interrupt service routine at the address of the ARM vector 0x1C.
This method does not use the vectoring, so that reading AIC_FVR must be performed at the very beginning of the
handler operation. However, this method saves the execution of a branch instruction.
23.7.4.5 Fast Forcing
The Fast Forcing feature of the advanced interrupt controller provides redirection of any normal Interrupt source on the
fast interrupt controller.
Fast Forcing is enabled or disabled by writing to the Fast Forcing Enable Register (AIC_FFER) and the Fast Forcing
Disable Register (AIC_FFDR). Writing to these registers results in an update of the Fast Forcing Status Register
(AIC_FFSR) that controls the feature for each internal or external interrupt source.
When Fast Forcing is disabled, the interrupt sources are handled as described in the previous pages.
When Fast Forcing is enabled, the edge/level programming and, in certain cases, edge detection of the interrupt source
is still active but the source cannot trigger a normal interrupt to the processor and is not seen by the priority handler.
If the interrupt source is programmed in level-sensitive mode and an active level is sampled, Fast Forcing results in the
assertion of the nFIQ line to the core.
If the interrupt source is programmed in edge-triggered mode and an active edge is detected, Fast Forcing results in the
assertion of the nFIQ line to the core.
The Fast Forcing feature does not affect the Source 0 pending bit in the Interrupt Pending Register (AIC_IPR).
The FIQ Vector Register (AIC_FVR) reads the contents of the Source Vector Register 0 (AIC_SVR0), whatever the
source of the fast interrupt may be. The read of the FVR does not clear the Source 0 when the fast forcing feature is used
and the interrupt source should be cleared by writing to the Interrupt Clear Command Register (AIC_ICCR).
All enabled and pending interrupt sources that have the fast forcing feature enabled and that are programmed in edge-
triggered mode must be cleared by writing to the Interrupt Clear Command Register. In doing so, they are cleared
independently and thus lost interrupts are prevented.
The read of AIC_IVR does not clear the source that has the fast forcing feature enabled.
The source 0, reserved to the fast interrupt, continues operatin g normally and becomes one of the Fast Interrupt sources.
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Figure 23-10. Fast Forcing
Source 0 _ FIQ Input Stage
Automatic Clear
Input Stage
Automatic Clear
Source n
AIC_IPR
AIC_IMR
AIC_FFSR
AIC_IPR
AIC_IMR
Priority
Manager
nFIQ
nIRQ
Read IVR if Source n is the current interrupt
and if Fast Forcing is disabled on Source n.
Read FVR if Fast Forcing is
disabled on Sources 1 to 31.
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23.7.5 Protect Mode
The Protect Mode permits reading the Interrupt Vector Register without performing the associated automatic operations.
This is necessary when working with a debug system. When a debugger, working either with a Debug Monitor or the
ARM processor's ICE, stops the applications and updates the opened windows, it might read the AIC User Interface and
thus the IVR. This has undesirable consequences:
If an enabled interrupt with a higher priority than the current one is pending, it is stacked.
If there is no enabled pending interrupt, the spurious vector is returned.
In either case, an End of Interrupt command is necessary to acknowledge and to restore the context of the AIC. This
operation is generally not performed by the debug system as the debug system would become strongly intrusive and
cause the application to enter an undesired state.
This is avoided by using the Protect Mode. Writing PROT in AIC_DCR (Debug Control Register) at 0x1 enables the
Protect Mode.
When the Protect Mode is enabled, the AIC performs interrupt stacking only when a write access is performed on the
AIC_IVR. Therefore, the Interrupt Service Routines must write (arbitrary data) to the AIC_IVR just after reading it. The
new context of the AIC, including the value of the Interrupt Status Register (AIC_ISR), is updated with the current
interrupt only when AIC_IVR is written.
An AIC_IVR read on its own (e.g., by a debugger), modifies neither the AIC context nor the AIC_ISR. Extra AIC_IVR
reads perform the same operations. However, it is recommended to not stop the processor between the read and the
write of AIC_IVR of the interrupt service routine to make sure the debugger does not modify the AIC context.
To summarize, in normal operating mode, the read of AIC_IVR performs the following operations within the AIC:
1. Calculates active interrupt (higher than current or spurious).
2. Determines and returns the vector of the active interrupt.
3. Memorizes the interrupt.
4. Pushes the current priority level onto the internal stack.
5. Acknowledges the interrupt.
However, while the Protect Mode is activated, only operations 1 to 3 are performed when AIC_IVR is read. Operations 4
and 5 are only performed by the AIC when AIC_IVR is written.
Software that has been written and debugged using the Protect Mode runs correctly in Normal Mode without
modification. However, in Normal Mode the AIC_IVR write has no effect and can be removed to optimize the code.
23.7.6 Spurious Interrupt
The Advanced Interrupt Controller features protection against spurious inte rrupts. A spurious interrupt is defined as being
the assertion of an interrupt source long enough for the AIC to assert the nIRQ, but no longer present when AIC_IVR is
read. This is most prone to occur when:
An external interrupt source is programmed in level-sensitive mode and an active level occurs for only a short time.
An internal interrupt source is programmed in level sensitive and the output signal of the corresponding embedded
peripheral is activated for a short time. (As in the case for the Watchdog.)
An interrupt occurs just a few cycles before the software begins to mask it, thus resulting in a pulse on the interrupt
source.
The AIC detects a spurious interrupt at the time the AIC_IVR is read while no enabled interrupt source is pending. When
this happens, the AIC returns the value stored by the programmer in AIC_SPU (Spurious Vector Register). The
programmer must store the address of a spurious interrupt handler in AIC_SPU as part of the application, to enable an as
fast as possible return to the normal execution flow. This handler writes in AIC_EOICR and performs a return from
interrupt.
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23.7.7 General Interrupt Mask
The AIC features a General Interrupt Mask bit to prevent interrupts from reaching the processor. Both the nIRQ and the
nFIQ lines are driven to their inactive state if the bit GMSK in AIC_DCR (Debug Control Register) is set. However, this
mask does not prevent waking up the processor if it has entered Idle Mode. This function facilitates synchronizing the
processor on a next event and, as soon as the event occurs, performs subsequent operations without having to handle
an interrupt. It is strongly recommended to use this mask with caution.
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23.8 Advanced Interrupt Controller (AIC ) User Interface
23.8.1 Base Address
The AIC is mapped at the address 0xFFFF F000. It has a total 4-Kbyte addressing space. This permits the vectoring
feature, as the PC-relative load/store instructions of the ARM processor support only an ± 4-Kbyte offset.
23.8.2 Register Mapping
Notes: 1. The reset value of this register depends on the level of the external interrupt source. All other sources are cleared at
reset, thus not pending.
2. PID2...PID31 bit fields refer to the identifiers as defined in the Peripheral Identifiers Section of the product datasheet.
Table 23-2. Regist er Mapping
Offset Register Name Access Reset
0000 Source Mode Register 0 AIC_SMR0 Read-write 0x0
0x04 Source Mode Register 1 AIC_SMR1 Read-write 0x0
--- --- --- --- ---
0x7C Source Mode Register 31 AIC_SMR31 Read-write 0x0
0x80 Source Vector Register 0 AIC_SVR0 Read-write 0x0
0x84 Source Vector Register 1 AIC_SVR1 Read-write 0x0
--- --- --- --- ---
0xFC Source Vector Register 31 AIC_SVR31 Read-write 0x0
0x100 Interrupt V ector Register AIC_IVR Read-only 0x0
0x104 FIQ Interrupt Vector Register AIC_FVR Read-only 0x0
0x108 Interrupt St atus Register AIC_ISR Read-only 0x0
0x10C Interrupt Pending Register(2) AIC_IPR Read-only 0x0(1)
0x110 Interrupt Mask Register(2) AIC_IMR Read-only 0x0
0x114 Core Interrupt Status Register AIC_CISR Read-only 0x0
0x118 Reserved --- --- ---
0x11C Reserved --- --- ---
0x120 Interrupt Enable Command Register(2) AIC_IECR Write-only ---
0x124 Interrupt Disable Command Register(2) AIC_IDCR Write-only ---
0x128 Interrupt Clear Command Register(2) AIC_ICCR Write-only ---
0x12C Interrupt Set Command Register(2) AIC_ISCR Write-only ---
0x130 End of Interrupt Command Register AIC_EOICR Write-only ---
0x134 Spurious Interrupt Vecto r Register AIC_SPU Read-write 0x0
0x138 Debug Control Register AIC_DCR Read-write 0x0
0x13C Reserved --- --- ---
0x140 Fa s t Forcing Enable Register(2) AIC_FFER Write-only ---
0x144 Fa s t Forcing Disable Register(2) AIC_FFDR Write-only ---
0x148 Fa s t Forcing Status Register(2) AIC_FFSR Read-only 0x0
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23.8.3 AIC Source Mode Register
Register Name: AIC_SMR0..AIC_SMR31
Access Type: Read-write
Reset Value: 0x0
• PRIOR: Priority Level
Programs the priority level for all sources except FIQ source (source 0).
The priority level can be between 0 (lowest) and 7 (highest).
The priority level is not used for the FIQ in the related SMR register AIC_SMRx.
• SRCTYPE: Inter rupt Source Type
The active level or edge is not programmable for the internal interrupt sources.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– SRCTYPE – – PRIOR
SRCTYPE Internal Interrup t Sources External Interrupt Sources
0 0 High level Sensitive Low level Sensitive
0 1 Positive edge triggered Negative edge triggered
1 0 High level Sensitive High level Sensitive
1 1 Positive edge triggered Positive edge triggered
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23.8.4 AIC Source Vector Register
Register Name: AIC_SVR0..AIC_SVR31
Access Type: Read-write
Reset Value: 0x0
• VECTOR: Source Vector
The user may store in these registers the addresses of the corresponding handler for each interrupt source.
23.8.5 AIC Interrupt Vector Register
Register Name: AIC_IVR
Access Type: Read-only
Reset Value: 0
• IRQV: Interrupt Vector Register
The Interrupt Vector Register contains the vector programmed by the user in the Source Vector Register corresponding to the
current interrupt.
The Source Vector Register is indexed using the current interrupt number when the Interrupt Vector Register is read.
When there is no current interrupt, the Interrupt Vector Register reads the value stored in AIC_SPU.
31 30 29 28 27 26 25 24
VECTOR
23 22 21 20 19 18 17 16
VECTOR
15 14 13 12 11 10 9 8
VECTOR
76543210
VECTOR
31 30 29 28 27 26 25 24
IRQV
23 22 21 20 19 18 17 16
IRQV
15 14 13 12 11 10 9 8
IRQV
76543210
IRQV
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23.8.6 AIC FIQ Vector Register
Register Name: AIC_FVR
Access Type: Read-only
Reset Value: 0
• FIQV: FIQ Vector Register
The FIQ Vector Register contains the vector programmed by the user in the Source Vector Register 0. When there is no fast inter-
rupt, the FIQ Vector Register reads the value stored in AIC_SPU.
23.8.7 AIC Interrupt Status Register
Register Name: AIC_ISR
Access Type: Read-only
Reset Value: 0
• IRQID: Current Interrupt Identifier
The Interrupt Status Register returns the current interrupt source number.
31 30 29 28 27 26 25 24
FIQV
23 22 21 20 19 18 17 16
FIQV
15 14 13 12 11 10 9 8
FIQV
76543210
FIQV
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––– IRQID
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23.8.8 AIC Interrupt Pending Register
Register Name: AIC_IPR
Access Type: Read-only
Reset Value: 0
• FIQ , SYS, PID2-PID31: Interrupt Pending
0 = Corresponding interrupt is not pending.
1 = Corresponding interrupt is pending.
23.8.9 AIC Interrupt Mask Register
Register Name: AIC_IMR
Access Type: Read-only
Reset Value: 0
• FIQ , SYS, PID2-PID31: Interrupt Mask
0 = Corresponding interrupt is disabled.
1 = Corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
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23.8.10 AIC Core Interrupt Status Register
Register Name: AIC_CISR
Access Type: Read-only
Reset Value: 0
• NFIQ: NFIQ Status
0 = nFIQ line is deactivated.
1 = nFIQ line is active.
• NIRQ: NIRQ Status
0 = nIRQ line is deactivated.
1 = nIRQ line is active.
23.8.11 AIC Interrupt Enable Command Register
Register Name: AIC_IECR
Access Type: Write-only
• FIQ , SYS, PID2-PID3: Interrupt Enable
0 = No effect.
1 = Enables corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––NIRQNIFQ
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
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23.8.12 AIC Interrupt Disable Command Register
Register Name: AIC_IDCR
Access Type: Write-only
• FIQ , SYS, PID2-PID31: Interrupt Disable
0 = No effect.
1 = Disables corresponding interrupt.
23.8.13 AIC Interrupt Clear Command Register
Register Name: AIC_ICCR
Access Type: Write-only
• FIQ , SYS, PID2-PID31: Interrupt Clear
0 = No effect.
1 = Clears corresponding interrupt.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
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23.8.14 AIC Interrupt Set Command Register
Register Name: AIC_ISCR
Access Type: Write-only
• FIQ , SYS, PID2-PID31: Interrupt Set
0 = No effect.
1 = Sets corresponding interrupt.
23.8.15 AIC End of Interrupt Command Register
Register Name: AIC_EOICR
Access Type: Write-only
The End of Interrupt Command Register is used by the interrupt routine to indicate that the interrupt treatment is complete. Any
value can be written because it is only necessary to make a write to this register location to signal the end of interrupt treatment.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS FIQ
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––––
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23.8.16 AIC Spurious Interrupt Vector Register
Register Name: AIC_SPU
Access Type: Read-write
Reset Value: 0
• SIVR: Spurious Interrupt Vector Register
The user may store the address of a spurious interrupt handler in th is register. The written value is returned in AIC_IVR in case of
a spurious interrupt and in AIC_FVR in case of a spurious fast interrupt.
23.8.17 AIC Debug Control Register
Register Name: AIC_DEBUG
Access Type: Read-write
Reset Value: 0
• PROT: Protection Mode
0 = The Protection Mode is disabled.
1 = The Protection Mode is enabled.
• GMSK: General Mask
0 = The nIRQ and nFIQ lines are normally controlled by the AIC.
1 = The nIRQ and nFIQ lines are tied to their inactive state.
31 30 29 28 27 26 25 24
SIVR
23 22 21 20 19 18 17 16
SIVR
15 14 13 12 11 10 9 8
SIVR
76543210
SIVR
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––GMSKPROT
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23.8.18 AIC Fast Forcing Enable Register
Register Name: AIC_FFER
Access Type: Write-only
• SYS, PID2-PID31: Fast Forcing Enable
0 = No effect.
1 = Enables the fast forcing feature on the corresponding interrupt.
23.8.19 AIC Fast Forcing Disable Register
Register Name: AIC_FFDR
Access Type: Write-only
• SYS, PID2-PID31: Fast Forcing Disable
0 = No effect.
1 = Disables the Fast Forcing feature on the corresponding interrupt.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS –
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS –
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23.8.20 AIC Fast Forcing Status Register
Register Name: AIC_FFSR
Access Type: Read-only
• SYS, PID2-PID31: Fast Forcing Status
0 = The Fast Forcing feature is disabled on the corresponding interrupt.
1 = The Fast Forcing feature is enabled on the corresponding interrupt.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 SYS –
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24. Clock Generator
24.1 Overview
The Clock Generator is made up of 1 PLL, a Main Oscillator, as well as an RC Oscillator .
It provides the following clocks:
SLCK, the Slow Clock, which is the only permanent clock within the system
MAINCK is the output of the Main Oscillator
PLLCK is the output of the Divider and PLL block
The Clock Generator User Interface is embedded within the Power Management Controller one and is described in
Section 25.9. However, the Clock Generator registers are named CKGR_.
24.2 Slow Clock RC Oscillator
The user has to take into account the possible drifts of the RC Oscillator. More details are given in the section “DC
Characteristics” of the product datasheet.
24.3 Main Oscillator
Figure 24-1 shows the Main Oscillator block diagram.
Figure 24-1. Main Oscillator Block Diagram
24.3.1 Main Oscillator Connections
The Clock Generator integrates a Main Oscillator that is designed for a 3 to 20 MHz fundamental crystal. The typical
crystal connection is illustrated in Figure 24-2. For further details on the electrical characteristics of the Main Oscillator,
see the section “DC Characteristics” of the product datasheet.
XIN
XOUT
MOSCEN
Main
Oscillator
Counter
OSCOUNT
MOSCS
MAINCK
Main Clock
Main Clock
Frequency
Counter
MAINF
MAINRDY
SLCK
Slow Clock
Main
Oscillator
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Figure 24-2. Typical Crystal Connection
24.3.2 Main Oscillator Startup Time
The startup time of the Main Oscillator is given in the DC Characteristics section of the product datasheet. The startup
time depends on the crystal frequency and decreases when the frequency rises.
24.3.3 Main Oscillator Control
To minimize the power required to start up the system, the main oscillator is disabled after reset and slow clock is
selected.
The software enables or disables the main oscillator so as to reduce power consumption by clearing the MOSCEN bit in
the Main Oscillator Register (CKGR_MOR).
When disabling the main oscillator by clearing the MOSCEN bit in CKGR_MOR, the MOSCS bit in PMC_SR is
automatically cleared, indicating the main clock is off.
When enabling the main oscillator, the user must initiate the main oscillator counter with a value corresponding to the
startup time of the oscillator. This startup time depends on the crystal frequency connected to the main oscillator.
When the MOSCEN bit and the OSCOUNT are written in CKGR_MOR to enable the main oscillator, the MOSCS bit in
PMC_SR (Status Register) is cleared and the counter starts counting down on the slow clock divided by 8 from the
OSCOUNT value. Since the OSCOUNT value is coded with 8 bits, the maximum startup time is about 62 ms.
When the counter reaches 0, the MOSCS bit is set, indicating that the main clock is valid. Setting the MOSCS bit in
PMC_IMR can trigger an interrupt to the processor.
24.3.4 Main Clock Frequency Counter
The Main Oscillator features a Main Clock frequency counter that provides the quartz frequency connected to the Main
Oscillator. Generally, this value is known by the system designer; however, it is useful for the boot program to configure
the device with the correct clock speed, independently of the application.
The Main Clock frequency counter starts incrementing at the Main Clock speed after the next rising edge of the Slow
Clock as soon as the Main Oscillator is stable, i.e., as soon as the MOSCS bit is set. Then, at the 16th falling edge of
Slow Clock, the MAINRDY bit in CKGR_MCFR (Main Clock Frequency Register) is set and the counter stops counting.
Its value can be read in the MAINF field of CKGR_MCFR and gives the number of Main Clock cycles during 16 periods of
Slow Clock, so that the frequency of the crystal connected on the Main Oscillator can be determined.
24.3.5 Main Oscillator Bypass
The user can input a clock on the device instead of connecting a crystal. In this case, the user has to provide the external
clock signal on the XIN pin. The input characteristics of the XIN pin under these conditions are given in the product
electrical characteristics section. The programmer has to be sure to set the OSCBYPASS bit to 1 and the MOSCEN bit to
0 in the Main OSC register (CKGR_MOR) for the external clock to operate properly.
1K
XIN XOUT GND
AT91SAM7X Microcontroller
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24.4 Divider and PLL Block
The PLL embeds an input divider to increase the accuracy of the resulting clock signals. However, the user must respect
the PLL minimum input frequency when programming the divider.
Figure 24-3 shows the block diagram of the divider and PLL block.
Figure 24-3. Divider and PLL Block Diagram
24.4.1 PLL Filter
The PLL requires connection to an external second-order filter through the PLLRC pin. Figure 24-4 shows a schematic of
these filters.
Figure 24-4. PLL Capacitors and Resistors
Values of R, C1 and C2 to be connected to the PLLRC pin must be calculated as a function of the PLL input frequency,
the PLL output frequency and the phase margin. A trade-off has to be found between output signal overshoot and startu p
time.
24.4.2 Divider and Phase Lock Loop Programming
The divider can be set between 1 and 255 in steps of 1. When a divider field (DIV) is set to 0, the output of the
corresponding divider and the PLL output is a continuous signal at level 0. On reset, each DIV field is set to 0, thus the
corresponding PLL input clock is set to 0.
The PLL allows multiplication of the divider’s outputs. The PLL clock signal has a frequency that depends on the
respective source signal frequency and on the parameters DIV and MUL. The factor applied to the source signal
frequency is (MUL + 1)/DIV. When MUL is written to 0, the corresponding PLL is disabled and its power consumption is
saved. Re-enabling the PLL can be performed by writing a value higher than 0 in the MUL field.
Whenever the PLL is re-enabled or one of its parameters is changed, the LOCK bit in PMC_SR is automatically cleared.
The values written in the PLLCOUNT field in CKGR_PLLR are loaded in the PLL counter. The PLL counter then
decrements at the speed of the Slow Clock until it reaches 0. At this time, the LOCK bit is set in PMC_SR and can trigger
an interrupt to the processor. The user has to load the number of Slow Clock cycles required to cover the PLL transient
Divider
PLLRC
DIV
PLL
MUL
PLLCOUNT
LOCK
OUT
SLCK
MAINCK PLLCK
PLL
Counter
GND
C1
C2
PLL
PLLRC
R
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time into the PLLCOUNT field. The transient time depends on the PLL filter. The initial state of the PLL and its target
frequency can be calculated using a specific tool provided by Atmel.
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25. Power Management Controller (PMC)
25.1 Description
The Power Management Controller (PMC) optimizes power consumption by controlling all system and user peripheral
clocks. The PMC enables/disables the clock inputs to many of the peripherals and the ARM Processor.
The Power Management Controller provides the following clocks:
MCK, the Master Clock, programmable from a few hundred Hz to the maximum operating frequency of the device.
It is available to the modules running permanently, such as the AIC and the Memory Controller.
Processor Clock (PCK), switched off when entering processor in idle mode.
Peripheral Clocks, typically MCK, provided to the embedded peripherals (USART, SSC, SPI, TWI, TC, MCI, etc.)
and independently controllable. In order to reduce the number of clock names in a product, the Peripheral Clocks
are named MCK in the product datasheet.
UDP Clock (UDPCK), required by USB Device Port operations.
Programmable Clock Outputs can be selected from the clocks provided by the clock generator and driven on the
PCKx pins.
25.2 Master Clock Controller
The Master Clock Controller provides selection and division of the Master Clock (MCK). MCK is the clock provided to all
the peripherals and the memory controller.
The Master Clock is selected from one of the clocks provided by the Clock Generator. Selecting the Slow Clock provides
a Slow Clock signal to the whole device. Selecting the Main Clock saves power consumption of the PLL.
The Master Clock Controller is made up of a clock selector and a prescaler.
The Master Clock selection is made by writing the CSS field (Clock Source Selection) in PMC_MCKR (Master Clock
Register). The prescaler supports the division by a power of 2 of the selected clock between 1 and 64. The PRES field in
PMC_MCKR programs the prescaler.
Each time PMC_MCKR is written to define a new Master Clock, the MCKRDY bit is cleared in PMC_SR. It reads 0 until
the Master Clock is established. Then, the MCKRDY bit is set and can trigger an interrupt to the processor. This feature
is useful when switching from a high-speed clock to a lower one to inform the software when the change is actually done.
Figure 25-1. Master Clock Controller
25.3 Processor Clock Controller
The PMC features a Processor Clock Controller (PCK) that implements the Processor Idle Mode. The Processor Clock
can be disabled by writing the System Clock Disable Register (PMC_SCDR). The status of this clock (at least for debug
purpose) can be read in the System Clock Status Register (PMC_SCSR).
SLCK Master Clock
Prescaler MCK
PRESCSS
MAINCK
PLLCK
To the Processor
Clock Controller (PCK)
PMC_MCKR PMC_MCKR
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The Processor Clock PCK is enabled after a reset and is automatically re-enabled by any enabled interrupt. The
Processor Idle Mode is achieved by disabling the Processor Clock, which is automatically re-enabled by any enabled fast
or normal interrupt, or by the reset of the product.
When the Processor Clock is disabled, the current instruction is finished before the clock is stopped, but this does not
prevent data transfers from other masters of the system bus.
25.4 USB Clock Controller
The USB Source Clock is the PLL output. If using the USB, the user must program the PLL to generate a 48 MHz, a 96
MHz or a 192 MHz signal with an accuracy of ± 0.25% depending on the USBDIV bit in CKGR_PLLR.
When the PLL output is stable, i.e., the LOCK bit is set:
The USB device clock can be enabled by setting the UDP bit in PMC_SCER. To save power on this peripheral
when it is not used, the user can set the UDP bit in PMC_SCDR. The UDP bit in PMC_SCSR gives the activity of
this clock. The USB device port require both the 48 MHz signal and the Master Clock. The Master Clock may be
controlled via the Master Clock Controller.
Figure 25-2. USB Clock Controller
25.5 Peripheral Clock Controller
The Power Management Controller controls the clocks of each embedded peripheral by the way of the Peripheral Clock
Controller. The user can individually enable and disable the Master Clock on the peripherals by writing into the Peripheral
Clock Enable (PMC_PCER) and Peripheral Clock Disable (PMC_PCDR) registers. The status of the peripheral clock
activity can be read in the Peripheral Clock Status Register (PMC_PCSR).
When a peripheral clock is disabled, the clock is immediately stopped. The peripheral clocks are automatically disabled
after a reset.
In order to stop a peripheral, it is recommended that the system software wait until the peripheral has executed its last
programmed operation before disabling the clock. This is to avoid data corruption or erroneous behavior of the system.
The bit number within the Peripheral Clock Control registers (PMC_PCER, PMC_PCDR, and PMC_PCSR) is the
Peripheral Identifier defined at the product level. Generally, the bit number corresponds to the interrupt source number
assigned to the peripheral.
25.6 Programmable Clock Output Controller
The PMC controls 4 signals to be output on external pins PCKx. Each signal can be independently programmed via the
PMC_PCKx registers.
PCKx can be independently selected between the Slow clock, the PLL output and the main clock by writing the CSS field
in PMC_PCKx. Each output signal can also be divided by a power of 2 between 1 and 64 by writing the PRES (Prescaler)
field in PMC_PCKx.
Each output signal can be enabled and disabled by writing 1 in the corresponding bit, PCKx of PMC_SCER and
PMC_SCDR, respectively. Status of the active programmable output clocks are given in the PCKx bits of PMC_SCSR
(System Clock Status Register).
USB
Source
Clock UDP Clock (UDPCK)
UDP
USBDIV
Divider
/1,/2,/4
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Moreover, like the PCK, a status bitin PMC_SR indicates that the Programmable Clock is actually what has been
programmed in the Programmable Clock registers.
As the Programmable Clock Controller does not manage with glitch prevention when switching clocks, it is strongly
recommended to disable the Programmable Clock before any configuration change and to re-enable it after the change
is actually performed.
25.7 Programming Sequence
1. Enabling the Main Oscillator:
The main oscillator is enabled by setting the MOSCEN field in the CKGR_MOR register. In some cases it may be
advantageous to define a start-up time. This can be achieved by writing a value in the OSCOUNT field in the
CKGR_MOR register.
Once this register has been correctly configured, the user must wait for MOSCS field in the PMC_SR register to be
set. This can be done either by polling the status register or by waiting the interrupt line to be raised if the associ-
ated interrupt to MOSCS has been enabled in the PMC_IER register.
Code Example: write_register(CKGR_MOR,0x00000701)
Start Up Time = 8 * OSCOUNT / SLCK = 56 Slow Clock Cycles.
So, the main oscillator will be enabled (MOSCS bit set) after 56 Slow Clock Cycles.
2. Checking the Main Oscillator Frequency (Optional):
In some situations the user may need an accurate measure of the main oscillator frequency. This measure can be
accomplished via the CKGR_MCFR register.
Once the MAINRDY field is set in CKGR_MCFR register, the user may read the MAINF field in CKGR_MCFR reg-
ister. This provides the number of main clock cycles within sixteen slow clock cycles.
3. Setting PLL and divider:
All parameters needed to configure PLL and the divider are located in the CKGR_PLLR register.
The DIV field is used to control divider itself. A value between 0 and 255 can be programmed. Divider output is
divider input divided by DIV parameter. By default DIV parameter is set to 0 which means that divider is turned off.
The OUT field is used to select the PLL B output frequency range.
The MUL field is the PLL multiplier factor. This parameter can be programmed between 0 and 2047. If MUL is set
to 0, PLL will be turned off, otherwise the PLL output frequency is PLL input frequency multiplied by (MUL + 1).
The PLLCOUNT field specifies the number of slow clock cycles before LOCK bit is set in the PMC_SR register
after CKGR_PLLR register has been written.
Once the PMC_PLL register has been written, the user must wait for the LOCK bit to be set in the PMC_SR regis-
ter. This can be done either by polling the status register or by waiting the interrupt line to be raised if the
associated interrupt to LOCK has been enabled in the PMC_IER register. All parameters in CKGR_PLLR can be
programmed in a single write operation. If at some stage one of the following parameters, MUL, DIV is modified,
LOCK bit will go low to indicate that PLL is not ready yet. When PLL is locked, LOCK will be set again. The user is
constrained to wait for LOCK bit to be set before using the PLL output clock.
The USBDIV field is used to control the additional divider by 1, 2 or 4, which generates the USB clock(s).
Code Example:
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write_register(CKGR_PLLR,0x00040805)
If PLL and divider are enabled, the PLL input clock is the main clock. PLL output clock is PLL input clock multiplied
by 5. Once CKGR_PLLR has been written, LOCK bit will be set after eight slow clock cycles.
4. Selection of Master Clock and Processor Clock
The Master Clock and the Processor Clock are configurable via the PMC_MCKR register.
The CSS field is used to select the Master Clock divider source. By default, the selected clock source is slow clock.
The PRES field is used to control the Master Clock prescaler. The user can choose between different values (1, 2,
4, 8, 16, 32, 64). Master Clock output is prescaler input divided by PRES parameter. By default, PRES parameter
is set to 1 which means that master clock is equal to slow clock.
Once the PMC_MCKR register has been written, the user mu st wait for the MCKRDY bit to be set in the PMC_SR
register. This can be done either by polling the status register or by waiting for the interrupt line to be raised if the
associated interrupt to MCKRDY has been enabled in the PMC_IER register.
The PMC_MCKR register must not be programmed in a single write operation. The preferred programming
sequence for the PMC_MCKR register is as follows:
If a new value for CSS field corresponds to PLL Clock,
Program the PRES field in the PMC_MCKR register.
Wait for the MCKRDY bit to be set in the PMC_SR register.
Program the CSS field in the PMC_MCKR register.
Wait for the MCKRDY bit to be set in the PMC_SR register.
If a new value for CSS field corresponds to Main Clock or Slow Clock,
Program the CSS field in the PMC_MCKR register.
Wait for the MCKRDY bit to be set in the PMC_SR register.
Program the PRES field in the PMC_MCKR register.
Wait for the MCKRDY bit to be set in the PMC_SR register.
If at some stage one of the following parameters, CSS or PRES, is modified, the MCKRDY bit will go low to indi-
cate that the Master Clock and the Processor Clock are not ready yet. The user must wait for MCKRDY bit to be
set again before using the Master and Processor Clocks.
Note: IF PLLx clock was selected as the Master Clock and the user decides to modify it by writing in CKGR_PLLR, the
MCKRDY flag will go low while PLL is unlocked. Once PLL is locked again, LOCK goes high and MCKRDY is
set.
While PLL is unlocked, the Master Clock selection is automatically changed to Main Clock. For further informa-
tion, see Section 25.8.2. “Clock Switching Waveforms” on page 177.
Code Example:
write_register(PMC_MCKR,0x00000001)
wait (MCKRDY=1)
write_register(PMC_MCKR,0x00000011)
wait (MCKRDY=1)
The Master Clock is main clock divided by 16.
The Processor Clock is the Master Clock.
5. Selection of Programmable clocks
Programmable clocks are controlled via registers; PMC_SCER, PMC_SCDR and PMC_SCSR.
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Programmable clocks can be enabled and/or disabled via the PMC_SCER and PMC_SCDR registers. Depending
on the system used, 4 Programmable clocks can be enabled or disabled. Th e PMC_SCSR provides a clear indica-
tion as to which Programmable clock is enabled. By default all Programmable clocks are disabled.
PMC_PCKx registers are used to configure Programmable clocks.
The CSS field is used to select the Programmable clock divider source. Four clock options are available: main
clock, slow clock, PLLCK. By default, the clock source selected is slow clock.
The PRES field is used to control the Programmable clock prescaler. It is possible to choose between different val-
ues (1, 2, 4, 8, 16, 32, 64). Programmable clock output is prescaler input divided by PRES parameter. By default,
the PRES parameter is set to 1 which means that master clock is equal to slow clock.
Once the PMC_PCKx register has been programmed, The corresponding Programmable clock must be enabled
and the user is constrained to wait for the PCKRDYx bit to be set in the PMC_SR register. This can be do ne either
by polling the status register or by waiting the interrupt line to be raised if the associated interrupt to PCKRDYx has
been enabled in the PMC_IER register. All parameters in PMC_PCKx can be programmed in a single write
operation.
If the CSS and PRES parameters are to be modified, the corresponding Programmable clock must be disabled
first. The parameters can then be modified. Once this has been done, the user must re-enable the Programmable
clock and wait for the PCKRDYx bit to be set.
Code Example:
write_register(PMC_PCK0,0x00000015)
Programmable clock 0 is main clock divided by 32.
6. Enabling Peripheral Clocks
Once all of the previous steps have been completed, the peripheral clocks can be enabled and/or disabled via reg-
isters PMC_PCER and PMC_PCDR.
Depending on the system used, 15 peripheral clocks can be enabled or disabled. The PMC_PCSR provides a
clear view as to which peripheral clock is enabled.
Note: Each enabled peripheral clock corresponds to Master Clock.
Code Examples:
write_register(PMC_PCER,0x00000110)
Peripheral clocks 4 and 8 are enabled.
write_register(PMC_PCDR,0x00000010)
Peripheral clock 4 is disabled.
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25.8 Clock Switching Details
25.8.1 Master Clock Switching Timings
Table 25-1 gives the worst case timings required for the Master Clock to switch from one selected clock to another one.
This is in the event that the prescaler is de-activated. When the prescaler is activated, an additional time of 64 clock
cycles of the new selected clock has to be added.
25.8.2 Clock Switching Waveforms
Figure 25-3. Switch Master Clock from Slow Clock to PLL Clock
Table 25-1. Clock Switching Timings (Worst Case)
From Main Clock SLCK PLL Clock
To
Main Clock – 4 x SLCK +
2.5 x Main Clock
3 x PLL Clock +
4 x SLCK +
1 x Main Clock
SLCK 0.5 x Main Clock +
4.5 x SLCK –3 x PLL Clock +
5 x SLCK
PLL Clock
0.5 x Main Clock +
4 x SLCK +
PLLCOUNT x SLCK +
2.5 x PLLx Clock
2.5 x PLL Clock +
5 x SLCK +
PLLCOUNT x SLCK
2.5 x PLL Clock +
4 x SLCK +
PLLCOUNT x SLCK
Slow Clock
LOCK
MCKRDY
Master Clock
Write PMC_MCKR
PLL Clock
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Figure 25-4. Switch Master Clock from Main Clock to Slow Clock
Figure 25-5. Change PLL Programming
Slow Clock
Main Clock
MCKRDY
Master Clock
Write PMC_MCKR
Main Clock
Main Clock
PLL Clock
LOCK
MCKRDY
Master Clock
Write CKGR_PLLR
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Figure 25-6. Programmable Clock Output Programming
PLL Clock
PCKRDY
PCKx Output
Write PMC_PCKx
Write PMC_SCER
Write PMC_SCDR PCKx is disabled
PCKx is enabled
PLL Clock is selected
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25.9 Power Management Controller (PMC) User Interface
Table 25-2. Regist er Mapping
Offset Register Name Access Reset
0x0000 System Clock Enable Register PMC_SCER Write-only –
0x0004 System Clock Disable Register PMC_SCDR Write-only –
0x0008 System Clock Status Register PMC _SCSR Read-only 0x01
0x000C Reserved – – –
0x0010 Peripheral Clock Enable Register PMC _PCER Write-only –
0x0014 Peripheral Clock Disable Re gister PMC_PCDR Write-only –
0x0018 Peripheral Clock Status Reg ister PMC_PCSR Read-only 0x0
0x001C Reserved – – –
0x0020 Main Oscillator Register CKGR_MOR Read-write 0x0
0x0024 Main Clock Freque ncy Register CKGR_MCFR Read-only 0x0
0x0028 Reserved – – –
0x002C PLL Register CKGR_PLLR Read-write 0x3F00
0x0030 Master Clock Register PMC_MCKR Read-write 0x0
0x0038 Reserved – – –
0x003C Reserved – – –
0x0040 Programmable Clock 0 Register PMC_PCK0 Read-write 0x0
0x0044 Programmable Clock 1 Register PMC_PCK1 Read-write 0x0
... ... ... ... ...
0x0060 Interrupt Enable Register PMC_IER Write-only --
0x0064 Interrupt Disable Register PMC_IDR Write-only --
0x0068 Status Register PMC_SR Re ad-only 0x08
0x006C Interrupt Mask Register PMC_IMR Read-only 0x0
0x0070 - 0x007C Reserved – – –
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25.9.1 PMC System Clock Enable Register
Register Name: PMC_SCER
Access Type: Write-only
• UDP: USB Device Port Clock Enable
0 = No effect.
1 = Enables the 48 MHz clock of the USB Device Port.
• PCKx: Programmable Clock x Output Enable
0 = No effect.
1 = Enables the corresponding Programmable Clock output.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––PCK3PCK2PCK1PCK0
76543210
UDP–––––––
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25.9.2 PMC System Clock Disable Register
Register Name: PMC_SCDR
Access Type: Write-only
• PCK: Processor Clock Disable
0 = No effect.
1 = Disables the Processor clock. This is used to enter the processor in Idle Mode.
• UDP: USB Device Port Clock Disable
0 = No effect.
1 = Disables the 48 MHz clock of the USB Device Port.
• PCKx: Programmable Clock x Output Disable
0 = No effect.
1 = Disables the corresponding Programmable Clock output.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––PCK3PCK2PCK1PCK0
76543210
UDP––––––PCK
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25.9.3 PMC System Clock St atus Register
Register Name: PMC_SCSR
Access Type: Read-only
• PCK: Processor Clock Status
0 = The Processor clock is disabled.
1 = The Processor clock is enabled.
• UDP: USB Device Port Clock Status
0 = The 48 MHz clock (UDPCK) of the USB Device Port is disabled.
1 = The 48 MHz clock (UDPCK) of the USB Device Port is enabled.
• PCKx: Programmable Clock x Output Status
0 = The corresponding Programmable Clock output is disabled.
1 = The corresponding Programmable Clock output is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––PCK3PCK2PCK1PCK0
76543210
UDP––––––PCK
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25.9.4 PMC Peripheral Clock Enable Register
Register Name: PMC_PCER
Access Type: Write-only
• PIDx: Peripheral Clock x Enable
0 = No effect.
1 = Enables the corresponding peripheral clock.
Note: PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
Note: Programming the control bit s of the Peripheral ID that are not implemented has no ef fect on the behavior of the PMC.
25.9.5 PMC Peripheral Clock Disable Register
Register Name: PMC_PCDR
Access Type: Write-only
• PIDx: Peripheral Clock x Disable
0 = No effect.
1 = Disables the corresponding peripheral clock.
Note: PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 - -
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 - -
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25.9.6 PMC Peripheral Clock Status Register
Register Name: PMC_PCSR
Access Type: Read-only
• PIDx: Peripheral Clock x Status
0 = The corresponding peripheral clock is disabled.
1 = The corresponding peripheral clock is enabled.
Note: PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
31 30 29 28 27 26 25 24
PID31 PID30 PID29 PID28 PID27 PID26 PID25 PID24
23 22 21 20 19 18 17 16
PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16
15 14 13 12 11 10 9 8
PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8
76543210
PID7 PID6 PID5 PID4 PID3 PID2 – –
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25.9.7 PMC Clock Generator Main Oscillator Register
Register Name: CKGR_MOR
Access Type: Read-write
• MOSCEN: Main Oscillator Enable
A crystal must be connected between XIN and XOUT.
0 = The Main Oscillator is disabled.
1 = The Main Oscillator is enabled. OSCBYPASS must be set to 0.
When MOSCEN is set, the MOSCS flag is set once the Main Oscillator startup time is achieved.
• OSCBYPASS: Oscillator Bypass
0 = No effect.
1 = The Main Oscillator is bypassed. MOSCEN must be set to 0. An external clock must be connected on XIN.
When OSCBYPASS is set, the MOSCS flag in PMC_SR is automatically set.
Clearing MOSCEN and OSCBYPASS bits allows resetting the MOSCS flag.
• OSCOUNT: Main Oscillator Start-up Time
Specifies the number of Slow Clock cycles multiplied by 8 for the Main Oscillator start-up time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
OSCOUNT
76543210
––––––OSCBYPASSMOSCEN
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25.9.8 PMC Clock Generator Main Clock Frequency Register
Register Name: CKGR_MCFR
Access Type: Read-only
• MAINF: Main Clock Frequency
Gives the number of Main Clock cycles within 16 Slow Clock periods.
• MAINRDY: Main Cloc k Ready
0 = MAINF value is not valid or the Main Oscillator is disabled.
1 = The Main Oscillator has been enabled previously and MAINF value is available.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––MAINRDY
15 14 13 12 11 10 9 8
MAINF
76543210
MAINF
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25.9.9 PMC Clock Generator PLL Register
Register Name: CKGR_PLLR
Access Type: Read-write
Possible limitations on PLL input frequencies and multiplier factors should be checked before using the PMC.
•DIV: Divider
• PLLCOUNT: PLL Counter
Specifies the number of slow clock cycles before the LOCK bit is set in PMC_SR after CKGR_PLLR is written.
• OUT: PLL Cloc k Frequency Range
To optimize clock performance, this field must be programmed as specified in “PLL Characteristics” in the Electrical Characteris-
tics section of the product datasheet.
• MUL: PLL Multiplier
0 = The PLL is deactivated.
1 up to 2047 = The PLL Clock frequency is the PLL input frequency multiplied by MUL+ 1.
• USBDIV: Divider for USB Clock
31 30 29 28 27 26 25 24
– – USBDIV – MUL
23 22 21 20 19 18 17 16
MUL
15 14 13 12 11 10 9 8
OUT PLLCOUNT
76543210
DIV
DIV Divider Selected
0 Divider output is 0
1 Divider is bypassed
2 - 255 Divider output is the selected clock divided by DIV.
USBDIV Divider for USB Clock(s)
0 0 Divider output is PLL clock output.
0 1 Divider output is PLL clock output divided by 2.
1 0 Divider output is PLL clock output divided by 4.
1 1 Reserved.
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25.9.10 PMC Master Clock Reg is t er
Register Name: PMC_MCKR
Access Type: Read-write
• CSS: Master Clock Selection
• PRES: Processor Clock Prescaler
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– – – PRES CSS
CSS Clock Source Selection
0 0 Slow Clock is selected
0 1 Main Clock is selected
10Reserved
1 1 PLL Clock is selected.
PRES Processor Clock
0 0 0 Selected clock
0 0 1 Selected clock divided by 2
0 1 0 Selected clock divided by 4
0 1 1 Selected clock divided by 8
1 0 0 S elected clock divided by 16
1 0 1 S elected clock divided by 32
1 1 0 S elected clock divided by 64
1 1 1 Reserved
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25.9.11 PMC Programmable Clock Register
Register Name: PMC_PCKx
Access Type: Read-write
• CSS: Master Clock Selection
• PRES: Programmable Clock Prescaler
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– – – PRES CSS
CSS Clock Source Selection
0 0 Slow Clock is selected
0 1 Main Clock is selected
10Reserved
1 1 PLL Clock is selected
PRES Programmable Clock
0 0 0 Selected clock
0 0 1 Selected clock divided by 2
0 1 0 Selected clock divided by 4
0 1 1 Selected clock divided by 8
1 0 0 S elected clock divided by 16
1 0 1 S elected clock divided by 32
1 1 0 S elected clock divided by 64
1 1 1 Reserved
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25.9.12 PMC Interrupt Enable Register
Register Name: PMC_IER
Access Type: Write-only
• MOSCS: Main Oscillator Status Interrupt Enable
• LOCK: PLL Lock Interrupt Enable
• MCKRDY : Master Clock Ready Interrupt Enable
• PCKRDYx: Programmable Clock Ready x Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
––––MCKRDYLOCK–MOSCS
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25.9.13 PMC Interrupt Disable Register
Register Name: PMC_IDR
Access Type: Write-only
• MOSCS: Main Oscillator Status Interrupt Disable
• LOCK: PLL Lo ck Interru p t Disable
• MCKRDY : Master Clock Ready Interrupt Disable
• PCKRDYx: Programmable Clock Ready x Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
––––MCKRDY
LOCK – MOSCS
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25.9.14 PMC Status Register
Register Name: PMC_SR
Access Type: Read-only
• MOSCS: MOSCS Flag Status
0 = Main oscillator is not stabilized.
1 = Main oscillator is stabilized.
• LOCK: PLL Lock Status
0 = PLL is not locked
1 = PLL is locked.
• MCKRDY : Master Clock Status
0 = Master Clock is not ready.
1 = Master Clock is ready.
• PCKRDYx: Programmable Clock Ready Status
0 = Programmable Clock x is not ready.
1 = Programmable Clock x is ready.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
––––MCKRDY
LOCK – MOSCS
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25.9.15 PMC Interrupt Mask Register
Register Name: PMC_IMR
Access Type: Read-only
• MOSCS: Main Oscillator Status Interrupt Mask
• LOCK: PLL Lo ck Interru p t Mask
• MCKRDY : Master Clock Ready Interrupt Mask
• PCKRDYx: Programmable Clock Ready x Interrupt Mask
0 = The corresponding interrupt is enabled.
1 = The corresponding interrupt is disabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––PCKRDY2PCKRDY1PCKRDY0
76543210
––––MCKRDY
LOCK – MOSCS
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26. Debug Unit (DBGU)
26.1 Overview
The Debug Unit provides a single entry point from the processor for access to all the debug capabilities of Atmel’s ARM-
based systems.
The Debug Unit features a two-pin UART that can be used for several debug and trace purposes and offers an ideal
medium for in-situ programming solutions and debug monitor communications. The Debug Unit two-pin UART can be
used standalone for general purpose serial communication. Moreover, the association with two peripheral data controller
channels permits packet handling for these tasks with processor time reduced to a minimum.
The Debug Unit also makes the Debug Co mmunication Channel (DCC) signals provided by the In-circuit Emulator of the
ARM processor visible to the software. These signals indicate the status of the DCC read and write registers and
generate an interrupt to the ARM processor, making possible the handling of the DCC under interrupt control.
Chip Identifier registers permit recognition of the device and its revision. These registers inform as to the sizes and types
of the on-chip memories, as well as the set of embedded peripherals.
Finally, the Debug Unit features a Force NTRST capability that enables the software to decide wh ether to prevent access
to the system via the In-circuit Emulator. This permits protection of the code, stored in ROM.
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26.2 Block Diagram
Figure 26-1. Debug Unit Functional Block Diagram
Figure 26-2. Debug Unit Application Example
Peripheral DMA Controller
Baud Rate
Generator
DCC
Handler
ICE
Access
Handler
Transmit
Receive
Chip ID
Interrupt
Control
Peripheral
Bridge
Parallel
Input/
Output
DTXD
DRXD
Power
Management
Controller
ARM
Processor
force_ntrst
COMMRX
COMMTX
MCK
nTRST
Power-on
Reset
dbgu_irq
APB Debug Unit
R
Table 26-1. Debug Unit Pin Description
Pin Name Description Type
DRXD Debug Receive Data Input
DTXD Debug Transmit Data Output
Debug Unit
RS232 Drivers
Programming Tool Trace Console Debug Console
Boot Program Debug Monitor Trace Manager
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26.3 Product Dependencies
26.3.1 I/O Lines
Depending on product integration, the Debug Unit pins may be multiplexed with PIO lines. In this case, the programmer
must first configure the corresponding PIO Controller to enable I/O lines operations of the Debug Unit.
26.3.2 Power Management
Depending on product integration, the Debug Unit clock may be controllable through the Power Management Controller.
In this case, the programmer must first configure the PMC to enable the Debug Unit clock. Usually, the peripheral
identifier used for this purpose is 1.
26.3.3 Interrupt Source
Depending on product integration, the Debug Unit interrupt line is connected to one of the interrupt sources of the
Advanced Interrupt Controller. Interrupt handling requires programming of the AIC before configuring the Debug Unit.
Usually, the Debug Unit interrupt line connects to the interrupt source 1 of the AIC, which may be shared with the real-
time clock, the system timer interrupt lines and other system peripheral interrupts, as shown in Figure 26-1. This sharing
requires the programmer to determine the source of the interrupt when the source 1 is triggered.
26.4 UART Operations
The Debug Unit operates as a UART, (asynchronous mode only) and supports only 8-bit character handling (with parity).
It has no clock pin.
The Debug Unit's UART is made up of a receiver and a transmitter that operate independently, and a common baud rate
generator. Receiver timeout and transmitter time guard are not implemented. However, all the imple mented features are
compatible with those of a standard USART.
26.4.1 Baud Rate Generator
The baud rate generator provides the bit period clock named baud rate clock to both the receiver and the transmitter.
The baud rate clock is the master clock divided by 16 times the value (CD) written in DBGU_BRGR (Baud Rate
Generator Register). If DBGU_BRGR is set to 0 , the baud rate clock is disabled and the Debug Unit's UART
remains inactive. The maximum allowable baud rate is Master Clock divided by 16. The minimum allowable baud
rate is Master Clock divided by (16 x 65536).
Figure 26-3. Baud Rate Generator
Baud Rate MCK
16 CD×
--------------------
=
MCK 16-bit Counter
0
Baud Rate
Clock
CD
CD
OUT
Divide
by 16
0
1
>1
Receiver
Sampling Clock
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26.4.2 Receiver
26.4.2.1 Receiver Reset, Enable and Disable
After device reset, the Debug Unit receiver is disabled and must be enabled before being used. The receiver can be
enabled by writing the control register DBGU_CR with the bit RXEN at 1. At this command, the receiver starts looking for
a start bit.
The programmer can disable the receiver by writing DBGU_CR with the bit RXDIS at 1. If the receiver is waiting for a
start bit, it is immediately stopped. However, if the receiver has already detected a start bit and is receiving the data, it
waits for the stop bit before actually stopping its operation.
The programmer can also put the receiver in its reset state by writing DBGU_CR with the bit RSTRX at 1. In doing so, the
receiver immediately stops its current operations and is disabled, whatever its current state. If RSTRX is applied when
data is being processed, this data is lost.
26.4.2.2 Start Detection and Data Sampling
The Debug Unit only supports asynchronous operations, and this affects only its receiver. The Debug Unit receiver
detects the start of a received character by sampling the DRXD signal until it detects a valid start bit. A low level (space)
on DRXD is interpreted as a valid start bit if it is detected for more than 7 cycles of the sampling clock, which is 16 times
the baud rate. Hence, a space that is longer than 7/16 of the bit period is detected as a valid start bit. A space which is
7/16 of a bit period or shorter is ignored and the receiver continues to wait for a valid start bit.
When a valid start bit has been detected, the receiver samples the DRXD at the theoretical midpoint of each bit. It is
assumed that each bit lasts 16 cycles of the sampling clock (1-bit period) so the bit sampling point is eight cycles (0.5-bit
period) after the start of the bit. The first sampling point is therefore 24 cycles (1.5-bit periods) after the falling edge of the
start bit was detected.
Each subsequent bit is sampled 16 cycles (1-bit period) after the previous one.
Figure 26-4. Start Bit Detection
Figure 26-5. Character Reception
26.4.2.3 Receiver Ready
When a complete character is received, it is transferred to the DBGU_RHR and the RXRDY status bit in DBGU_SR
(Status Register) is set. The bit RXRDY is automatically cleared when the receive holding register DBGU_RHR is read.
Sampling Clock
DRXD
True Start
Detection D0
Baud Rate
Clock
D0 D1 D2 D3 D4 D5 D6 D7
DRXD
True Start Detection
Sampling Parity Bit Stop Bit
Example: 8-bit, parity enabled 1 stop
1 bit
period
0.5 bit
period
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Figure 26-6. Receiver Ready
26.4.2.4 Receiver Overrun
If DBGU_RHR has not been read by the software (or the Peripheral Data Controller) since the last transfer, the RXRDY
bit is still set and a new character is received, the OVRE status bit in DBGU_SR is set. OVRE is cleared when the
software writes the control register DBGU_CR with the bit RSTSTA (Reset Status) at 1.
Figure 26-7. Receiver Overrun
26.4.2.5 Parity Error
Each time a character is received, the receiver calculates the parity of the received data bits, in accordance with the field
PAR in DBGU_MR. It then compares the result with the received parity bit. If different, the parity error bit PARE in
DBGU_SR is set at the same time the RXRDY is set. The parity bit is cleared when the control register DBGU_CR is
written with the bit RSTSTA (Reset Status) at 1. If a new character is received before the reset status command is
written, the PARE bit remains at 1.
Figure 26-8. Parity Error
26.4.2.6 Receiver Framing Error
When a start bit is detected, it generates a character recept ion when all the data bits have been sampled. The stop bit is
also sampled and when it is detected at 0, the FRAME (Framing Error) bit in DBGU_SR is set at the same time the
RXRDY bit is set. The bit FRAME remains high until the control register DBGU_CR is written with the bit RSTSTA at 1.
Figure 26-9. Receiver Framing Error
D0 D1 D2 D3 D4 D5 D6 D7 PS SD0 D1 D2 D3 D4 D5 D6 D7 P
DRXD
Read DBGU_RHR
RXRDY
D0 D1 D2 D3 D4 D5 D6 D7 PS SD0 D1 D2 D3 D4 D5 D6 D7 P
DRXD
RSTSTA
RXRDY
OVRE
stop stop
stop
D0 D1 D2 D3 D4 D5 D6 D7 PS
DRXD
RSTSTA
RXRDY
PARE
Wrong Parity Bit
D0 D1 D2 D3 D4 D5 D6 D7 PS
DRXD
RSTSTA
RXRDY
FRAME
Stop Bit
Detected at 0
stop
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26.4.3 Transmitter
26.4.3.1 Transmitter Reset, Enable and Disable
After device reset, the Debug Unit transmitter is disabled and it must be enabled before being used. The transmitter is
enabled by writing the control register DBGU_CR with the bit TXEN at 1. From this command, the transmitter waits for a
character to be written in the Transmit Holding Register DBGU_THR before actually starting the transmission.
The programmer can disable the transmitter by writing DBGU_CR with the bit TXDIS at 1. If the transmitter is not
operating, it is immediately stopped. However, if a chara cter is being processed into the Shift Register and/or a character
has been written in the Transmit Holding Register, the characters are completed before the transmitter is actually
stopped.
The programmer can also put the transmitter in its reset state by writing the DBGU_CR with the bit RSTTX at 1. This
immediately stops the transmitter, whether or not it is processing characters.
26.4.3.2 Transmit Format
The Debug Unit transmitter drives the pin DTXD at the baud rate clock speed. The line is driven depending on the format
defined in the Mode Register and the data stored in the Shift Register. One start bit at level 0, then the 8 data bits, from
the lowest to the highest bit, one optional parity bit and one stop bit at 1 are consecutively shifted out as shown on the
following figure. The field PARE in the mode register DBGU_MR defines whether or not a parity bit is shifted out. When a
parity bit is enabled, it can be selected between an odd parity, an even parity, or a fixed space or mark bit.
Figure 26-10. Character Transmission
26.4.3.3 Transmitter Control
When the transmitter is enabled, the bit TXRDY (Transmitter Ready) is set in the status register DBGU_SR. The
transmission starts when the programmer writes in the Transmit Holding Register DBGU_THR, and after the written
character is transferred from DBGU_THR to the Shift Register. The bit TXRDY remains high until a second character is
written in DBGU_THR. As soon as the first character is completed, the last character written in DBGU_THR is transferred
into the shift register and TXRDY rises again, showing that the holding register is empty.
When both the Shift Register and the DBGU_THR are empty, i.e., all the characters written in DBGU_THR have been
processed, the bit TXEMPTY rises after the last stop bit has been completed.
D0 D1 D2 D3 D4 D5 D6 D7
DTXD
Start
Bit Parity
Bit Stop
Bit
Example: Parity enabled
Baud Rate
Clock
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Figure 26-11. Transmitter Control
26.4.4 Peripheral Data Controller
Both the receiver and the transmitter of the Debug Unit's UART are generally connected to a Peripheral Data Controller
(PDC) channel.
The peripheral data controller channels are programmed via registers that are mapped within the Debug Unit user
interface from the offset 0x100. The status bits are reported in the Debug Unit status register DBGU_SR and can
generate an interrupt.
The RXRDY bit triggers the PDC channel data transfer of the receiver. This results in a read of the data in DBGU_RHR.
The TXRDY bit triggers the PDC channel data transfer of the transmitter. This results in a write of a data in DBGU_THR.
26.4.5 Test Modes
The Debug Unit supports three tests modes. These modes of operation are programmed by using the field CHMODE
(Channel Mode) in the mode register DBGU_MR.
The Automatic Echo mode allows bit-by-bit retransmission. When a bit is received on the DRXD line, it is sent to the
DTXD line. The transmitter operates normally, but has no effect on the DTXD line.
The Local Loopback mode allows the transmitted characters to be received. DTXD and DRXD pins are no t used and the
output of the transmitter is internally connected to the input of the receiver. The DRXD pin level has no effect and the
DTXD line is held high, as in idle state.
The Remote Loopback mode directly connects the DRXD pin to the DTXD line. The transmitter and the receiver are
disabled and have no effect. This mode allows a bit-by-bit retransmission.
DBGU_THR
Shift Register
DTXD
TXRDY
TXEMPTY
Data 0 Data 1
Data 0
Data 0
Data 1
Data 1S SPP
Write Data 0
in DBGU_THR Write Data 1
in DBGU_THR
stop
stop
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Figure 26-12. Test Modes
26.4.6 Debug Communication Channel Support
The Debug Unit handles the signals COMMRX and COMMTX that come from the Debug Communication Channel of the
ARM Processor and are driven by the In-circuit Emulator.
The Debug Communication Channel contains two registers that are accessible through the ICE Breaker on the JTAG
side and through the coprocessor 0 on the ARM Processor side.
As a reminder, the following instructions are used to read and write the Debug Communication Channel:
MRC p14, 0, Rd, c1, c0, 0
Returns the debug communication data read register into Rd
MCR p14, 0, Rd, c1, c0, 0
Writes the value in Rd to the debug communication data write register.
The bits COMMRX and COMMTX, which indicate, respectively, that the read register has been written by the debugger
but not yet read by the processor, and that the write register has been written by the processor and not yet read by the
debugger, are wired on the two highest bits of the status register DBGU_SR. These bits can generate an interrupt. This
feature permits handling under interrupt a debug link between a debug monitor running on the target system and a
debugger.
26.4.7 Chip Identifier
The Debug Unit features two chip identifier registers, DBGU_CIDR (Chip ID Register) and DBGU_EXID (Extension ID).
Both registers contain a hard-wired value that is read-only. The first register contains the following fields:
EXT - shows the use of the extension identifier register
Receiver
Transmitter Disabled
RXD
TXD
Receiver
Transmitter Disabled
RXD
TXD
VDD
Disabled
Receiver
Transmitter Disabled
RXD
TXD
Disabled
Automatic Echo
Local Loopback
Remote Loopback VDD
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NVPTYP and NVPSIZ - identifies the type of embedded non-volatile memory and its size
ARCH - identifies the set of embedded peripheral
SRAMSIZ - indicates the size of the embedded SRAM
EPROC - indicates the embedded ARM processor
VERSION - gives the revision of the silicon
The second register is device-dependent and reads 0 if the bit EXT is 0.
26.4.8 ICE Access Prevention
The Debug Unit allows blockage of access to the system through the ARM processor's ICE interface. This feature is
implemented via the register Force NTRST (DBGU_FNR), that allows assertion of the NTRST signal of the ICE Interface.
Writing the bit FNTRST (Force NTRST) to 1 in this register prevents any activity on the TAP controller.
On standard devices, the FNTRST bit resets to 0 and thus does not prevent ICE access.
This feature is especially useful on custom ROM devices for customers who do not want their on-chip code to be visible.
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26.5 Debug Unit (DBGU) User Interface
Table 26-2. Regist er Mapping
Offset Register Name Access Reset
0x0000 Control Register DBGU_CR Write-only –
0x0004 Mode Register DBGU_MR Read-write 0x0
0x0008 Interrupt Enable Register DBGU_IER Write-only –
0x000C Interrupt Disable Register DBGU_IDR Write-only –
0x0010 Interrupt Mask Register DBGU_IMR Read-only 0x0
0x0014 Sta tus Reg ister DBGU_SR Read-only –
0x0018 Receive Holding Register DBGU_RHR Read-on ly 0x0
0x001C Transmit Holding Register DBGU_THR Write-only –
0x0020 Baud Rate Generator Register DBGU_BRGR Read-write 0x0
0x0024 - 0x003C Reserved – – –
0x0040 Chi p ID Register DBGU_CIDR Read-only –
0x0044 Chip ID Extension Register DBGU_EXID Read-only –
0x0048 Force NTRST Register DBGU_FNR Read-write 0x0
0x004C - 0x00FC Reserved – – –
0x0100 - 0x0124 PDC Area – – –
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26.5.1 Debug Unit Control Register
Name: DBGU_CR
Access Type: Write-only
• RSTRX: Reset Receiver
0 = No effect.
1 = The receiver logic is reset and disabled. If a character is being received, the reception is aborted.
• RSTTX: Rese t Transmitter
0 = No effect.
1 = The transmitter logic is reset and disabled. If a character is being transmitted, the transmission is aborted.
• RXEN: Receiver Enable
0 = No effect.
1 = The receiver is enabled if RXDIS is 0.
• RXDIS: Receiver Dis able
0 = No effect.
1 = The receiver is disabled. If a character is being processed and RSTRX is not set, the character is completed before the
receiver is stopped.
• TXEN: Transmitter Enable
0 = No effect.
1 = The transmitter is enabled if TXDIS is 0.
• TXDIS: Transmitter Disable
0 = No effect.
1 = The transmitter is disabled. If a character is being processed and a character has been written the DBGU_THR and RSTTX is
not set, both characters are completed before the transmitter is stopped.
• RSTSTA: Reset Status Bits
0 = No effect.
1 = Resets the status bits PARE, FRAME and OVRE in the DBGU_SR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––
RSTSTA
76543210
TXDIS TXEN RXDIS RXEN RSTTX RSTRX ––
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26.5.2 Debug Unit Mode Register
Name: DBGU_MR
Access Type: Read-write
• PAR: Parity Type
• CHMODE: Channel Mode
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CHMODE –– PAR –
76543210
––––––––
PAR Parity Type
0 0 0 Even parity
001Odd parity
0 1 0 Space: parity forced to 0
0 1 1 Mark: parity forced to 1
1 x x No parity
CHMODE Mode Description
0 0 Normal Mode
0 1 Automatic Echo
1 0 Local Loopback
1 1 Remote Loopback
207
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26.5.3 Debug Unit Interrupt Enable Register
Name: DBGU_IER
Access Type: Write-only
• RXRDY: Enable RXRDY Interrupt
• TXRDY: Enable TXRDY Interrupt
• ENDRX: Enable End of Receive Transfer Interrupt
• ENDTX: Enable End of Transmit Interrupt
• OVRE: Enable Overrun Error Interrupt
• FRAME: Enable Framing Error Interrupt
• PARE: Enable Parity Erro r Interrupt
• TXEMPTY: Enable TXEMPTY Interrupt
• TXBUFE: Enable Buffer Empty Interrupt
• RXBUFF: Enable Buffer Full Interrupt
• COMMTX: Enable COMMTX (from ARM) Interrupt
• COMMRX: Enable COMMRX (from ARM) Interrupt
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
COMMRX COMMTX ––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
208
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26.5.4 Debug Unit Interrupt Disable Register
Name: DBGU_IDR
Access Type: Write-only
• RXRDY: Disable RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Disable End of Receive Transfer Interrupt
• ENDTX: Disable End of Transmit Interrupt
• OVRE: Disable Overrun Error Interrupt
• FRAME: Disable Framing Error Interrupt
• PARE: Disable Parity Error Interrupt
• TXEMPTY: Disable TXEMPTY Interrupt
• TXBUFE: Disable Buffer Empty Interrupt
• RXBUFF: Disabl e Buffer Full Interrupt
• COMMTX: Disable COMMTX (from ARM) Interrupt
• COMMRX: Disable COMMRX (from ARM) Interrupt
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
COMMRX COMMTX ––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
209
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26.5.5 Debug Unit Interrupt Mask Regi st er
Name: DBGU_IMR
Access Type: Read-only
• RXRDY: Mask RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Mask End of Receive Transfer Interrupt
• ENDTX: Mask End of Transmit Interrupt
• OVRE: Mask Overrun Error Interrupt
• FRAME: Mask Framing Error Interrupt
• PARE: Mask Parity Error Interrupt
• TXEMPTY: Mask TXEMPTY Interrupt
• TXBUFE: Mask TXBUFE Interrupt
• RXBUFF: Mask RXBUFF Interrupt
• COMMTX: Mask COMMTX Interrupt
• COMMRX: Mask COMMRX Interrupt
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
COMMRX COMMTX ––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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26.5.6 Debug Unit Status Register
Name: DBGU_SR
Access Type: Read-only
• RXRDY: Receiver Ready
0 = No character has been received since the last read of the DBGU_RHR or the receiver is disabled.
1 = At least one complete character has been received, transferred to DBGU_RHR and not yet read.
• TXRDY: Transmitter Ready
0 = A character has been written to DBGU_THR and not yet transferred to the Shift Register, or the transmitter is disabled.
1 = There is no character written to DBGU_THR not yet transferred to the Shift Register.
• ENDRX: End of Receiver Transfer
0 = The End of Transfer signal from the receiver Peripheral Data Controller channel is inactive.
1 = The End of Transfer signal from the receiver Peripheral Data Controller channel is active.
• ENDTX: End of Transmitter Transfer
0 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is inactive.
1 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is active.
• OVRE: Overrun Error
0 = No overrun error has occurred since the last RSTSTA.
1 = At least one overrun error has occurred since the last RSTSTA.
• FRAME: Framing Error
0 = No framing error has occurred since the last RSTSTA.
1 = At least one framing error has occurred since the last RSTSTA.
• PARE: Parity Error
0 = No parity error has occurred since the last RSTSTA.
1 = At least one parity error has occurred since the last RSTSTA.
• TXEMPTY: Transmitter Empty
0 = There are characters in DBGU_THR, or characters being processed by the transmitter, or the transmitter is disabled.
1 = There are no characters in DBGU_THR and there are no characters being processed by the transmitter.
• TXBUFE: Transmission Buffer Empty
31 30 29 28 27 26 25 24
COMMRX COMMTX ––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––
RXBUFF TXBUFE –TXEMPTY –
76543210
PARE FRAME OVRE ENDTX ENDRX –TXRDY RXRDY
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0 = The buffer empty signal from the transmitter PDC channel is inactive.
1 = The buffer empty signal from the transmitter PDC channel is active.
• RXBUFF: Receive Buffer Full
0 = The buffer full signal from the receiver PDC channel is inactive.
1 = The buffer full signal from the receiver PDC channel is active.
• COMMTX: Debug Communication Channel Write Status
0 = COMMTX from the ARM processor is inactive.
1 = COMMTX from the ARM processor is active.
• COMMRX: Debug Communication Channel Read Status
0 = COMMRX from the ARM processor is inactive.
1 = COMMRX from the ARM processor is active.
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26.5.7 Debug Unit Receiver Holding Register
Name: DBGU_RHR
Access Type: Read-only
• RXCHR: Received Character
Last received character if RXRDY is set.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RXCHR
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26.5.8 Debug Unit Transmit Holding Register
Name: DBGU_THR
Access Type: Write-only
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TXCHR
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26.5.9 Debug Unit Baud Rate Generator Register
Name: DBGU_BRGR
Access Type: Read-write
• CD: Clock Divisor
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CD
76543210
CD
CD Baud Rate Clock
0 Disabled
1MCK
2 to 65535 MCK / (CD x 16)
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26.5.10 Debug Unit Chip ID Register
Name: DBGU_CIDR
Access Type: Read-only
• VERSION: Version of the Device
• EPROC: Embedded Processor
• NVPSIZ: Nonvolatile Program Memory Size
31 30 29 28 27 26 25 24
EXT NVPTYP ARCH
23 22 21 20 19 18 17 16
ARCH SRAMSIZ
15 14 13 12 11 10 9 8
NVPSIZ2 NVPSIZ
76543210
EPROC VERSION
EPROC Processor
0 0 1 ARM946ES™
0 1 0 ARM7TDMI
100ARM920T
™
1 0 1 ARM926EJS™
NVPSIZ Size
0000None
00018K bytes
001016K bytes
001132K bytes
0100Reserved
010164K bytes
0110Reserved
0111128K bytes
1000Reserved
1001256K bytes
1010512K bytes
1011Reserved
11001024K bytes
1101Reserved
11102048K bytes
1111Reserved
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• NVPSIZ2 Second Nonvolatile Program Memory Size
• SRAMSIZ: Internal SRAM Size
NVPSIZ2 Size
0000None
00018K bytes
001016K bytes
001132K bytes
0100Reserved
010164K bytes
0110Reserved
0111128K bytes
1000Reserved
1001256K bytes
1010512K bytes
1011Reserved
11001024K bytes
1101Reserved
11102048K bytes
1111Reserved
SRAMSIZ Size
0000Reserved
00011K bytes
00102K bytes
00116K bytes
0100112K bytes
01014K bytes
011080K bytes
0111160K bytes
10008K bytes
100116K bytes
101032K bytes
101164K bytes
1100128K bytes
1101256K bytes
111096K bytes
1111512K bytes
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• ARCH: Architecture Identifier
• NVPTYP: Nonvolatile Program Memory Type
• EXT: Extension Flag
0 = Chip ID has a single register definition without extension
1 = An extended Chip ID exists.
ARCH
ArchitectureHex Bin
0x19 0001 1001 AT91SAM9xx Series
0x29 0010 1001 AT91SAM9XExx Series
0x34 0011 0100 AT 91x34 Series
0x37 0011 0111 CAP7 Series
0x39 0011 1001 CAP9 Series
0x3B 0011 1011 CAP11 Series
0x40 0100 0000 AT91x40 Series
0x42 0100 0010 AT91x42 Series
0x55 0101 0101 AT91x55 Series
0x60 0110 0000 AT91SAM7Axx Series
0x61 0110 0001 AT91SAM7AQxx Series
0x63 0110 0011 AT91x63 Series
0x70 0111 0000 AT91SAM7Sxx Series
0x71 0111 0001 AT91SAM7XCxx Series
0x72 0111 0010 AT91SAM7SExx Series
0x73 0111 0011 AT91SAM7Lxx Series
0x75 0111 0101 AT91SAM7Xxx Series
0x92 1001 0010 AT91x92 Series
0xF0 1111 000 0 AT75Cxx Series
NVPTYP Memory
000ROM
0 0 1 ROMless or on-chip Flash
1 0 0 SRAM emulati n g ROM
0 1 0 Embedded F lash Memory
011
ROM and Embedded Fla s h Memory
NVPSIZ is ROM size
NVPSIZ2 is Flash size
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26.5.11 Debug Unit Chip ID Extension Register
Name: DBGU_EXID
Access Type: Read-only
• EXID: Chip ID Extension
Reads 0 if the bit EXT in DBGU_CIDR is 0.
26.5.12 Debug Unit Force NTRST Register
Name: DBGU_FNR
Access Type: Read-write
• FNTRST: Force NTRST
0 = NTRST of the ARM processor’s TAP controller is driven by the power_on_reset signal.
1 = NTRST of the ARM processor’s TAP controller is held low.
31 30 29 28 27 26 25 24
EXID
23 22 21 20 19 18 17 16
EXID
15 14 13 12 11 10 9 8
EXID
76543210
EXID
31 30 29 28 27 26 25 24
––––––– –
23 22 21 20 19 18 17 16
––––––– –
15 14 13 12 11 10 9 8
––––––– –
7654321 0
–––––––
FNTRST
219
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27. Parallel Input/Output Controller (PIO)
27.1 Overview
The Parallel Input/Output Controller (PIO) manages up to 32 fully programmable input/output lines. Each I/O line may be
dedicated as a general-purpose I/O or be assigned to a function of an embedded peripheral. This assures effective
optimization of the pins of a product.
Each I/O line is associated with a bit number in all of the 32-bit registers of the 32-bit wide User Interface.
Each I/O line of the PIO Controller features:
An input change interrupt enabling level change detection on any I/O line.
A glitch filter providing rejection of pulses lower than one-half of clock cycle.
Multi-drive capability similar to an open drain I/O line.
Control of the the pull-up of the I/O line.
Input visibility and output control.
The PIO Controller also features a synchronous output providing up to 32 bits of data output in a single write operation.
27.2 Block Diagram
Figure 27-1 . Block Diagram
Embedded
Peripheral
Embedded
Peripheral
PIO Interrupt
PIO Controller
Up to 32 pins
PMC
Up to 32
peripheral IOs
Up to 32
peripheral IOs
PIO Clock
APB
AIC
Data, Enable
PIN 31
PIN 1
PIN 0
Data, Enable
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6120K–ATARM–11-Feb-14
Figure 27-2. Applica tio n Bloc k Diag ra m
27.3 Product Dependencies
27.3.1 Pin Multiplexing
Each pin is configurable, according to product definition as either a general-purpose I/O line only, or as an I/O line
multiplexed with one or two peripheral I/Os. As the multiplexing is hardware-defined and thus product-dependent, the
hardware designer and programmer must carefully determine the configuration of the PIO controllers required by their
application. When an I/O line is general-purpose only, i.e. not multiplexed with any peripheral I/O, programming of the
PIO Controller regarding the assignment to a peripheral has no effect and only the PIO Controller can control how the pin
is driven by the product.
27.3.2 External Interrupt Lines
The interrupt signals FIQ and IRQ0 to IRQn are most generally multiplexed through the PIO Controllers. However, it is
not necessary to assign the I/O line to the interrupt function as the PIO Controller has no effect on inputs and the interrupt
lines (FIQ or IRQs) are used only as inputs.
27.3.3 Power Management
The Power Management Controller controls the PIO Controller clock in order to save power. Writing any of the registers
of the user interface does not require the PIO Controller clock to be enabled. This means that the configuration of t he I/O
lines does not require the PIO Controller clock to be enabled.
However, when the clock is disabled, not all of the features of the PIO Controller are available. Note that the Input
Change Interrupt and the read of the pin level require the clock to be validated.
After a hardware reset, the PIO clock is disabled by default.
The user must configure the Power Management Controller before any access to the input line information.
27.3.4 Interrupt Generation
For interrupt handling, the PIO Controllers are considered as user peripherals. This means that the PIO Controller
interrupt lines are connected among the interrupt sources 2 to 31. Refer to the PIO Controller peripheral identifier in the
product description to identify the interrupt sources dedicated to the PIO Controllers.
The PIO Controller interrupt can be generated only if the PIO Controller clock is enabled.
On-Chip Peripherals
PIO Controller
On-Chip Peripheral Drivers
Control & Command
Driver
Keyboard Driver
Keyboard Driver General Purpose I/Os External Devices
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27.4 Functional Description
The PIO Controller features up to 32 fully-programmable I/O lines. Most of the control logic associated to each I/O is
represented in Figure 27-3. In this description each signal shown represents but one of up to 32 possible indexes.
Figure 27-3. I/O Line Control Lo gi c
27.4.1 Pull-up Resistor Co nt rol
Each I/O line is designed with an embedded pull-up resistor. The pull-up resistor can be enabled or disabled by writing
respectively PIO_PUER (Pull-up Enable Register) and PIO_PUDR (Pull-up Disable Resistor). Writing in these registers
1
0
1
0
1
0
Glitch
Filter
Peripheral B
Input
Peripheral A
Input
1
0
PIO_IFDR[0]
PIO_IFSR[0]
PIO_IFER[0]
Edge
Detector
PIO_PDSR[0] PIO_ISR[0]
PIO_IDR[0]
PIO_IMR[0]
PIO_IER[0]
PIO Interrupt
(Up to 32 possible inputs)
PIO_ISR[31]
PIO_IDR[31]
PIO_IMR[31]
PIO_IER[31]
Pad
1
0
PIO_PUDR[0]
PIO_PUSR[0]
PIO_PUER[0]
PIO_MDDR[0]
PIO_MDSR[0]
PIO_MDER[0]
PIO_CODR[0]
PIO_ODSR[0]
PIO_SODR[0]
PIO_PDR[0]
PIO_PSR[0]
PIO_PER[0]
1
0
1
0
PIO_BSR[0]
PIO_ABSR[0]
PIO_ASR[0]
Peripheral B
Output Enable
Peripheral A
Output Enable
Peripheral B
Output
Peripheral A
Output
PIO_ODR[0]
PIO_OSR[0]
PIO_OER[0]
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6120K–ATARM–11-Feb-14
results in setting or clearing the corresponding bit in PIO_PUSR (Pull-up Status Register). Reading a 1 in PIO_PUSR
means the pull-up is disabled and reading a 0 means the pull-up is enabled.
Control of the pull-up resistor is possible regardless of the configuration of the I/O line.
After reset, all of the pull-ups are enabled, i.e. PIO_PUSR resets at the value 0x0.
27.4.2 I/O Line or Peripheral Function Selection
When a pin is multiplexed with one or two peripheral functions, the selection is controlled with the registers PIO_PER
(PIO Enable Register) and PIO_PDR (PIO Disable Register). The r egister PIO_PSR (PIO Status Register) is the result of
the set and clear registers and indicates whether the pin is controlled by the corresponding peripheral or by the PIO
Controller. A value of 0 indicates that the pin is controlled by the corresponding on-chip peripheral selected in the
PIO_ABSR (AB Select Status Register). A value of 1 indicates the pin is controlled by the PIO controller.
If a pin is used as a general purpose I/O line (not multiplexed with an on-chip peripheral), PIO_PER and PIO_PDR have
no effect and PIO_PSR returns 1 for the corresponding bit.
After reset, most generally, the I/O lines are controlled by the PIO controller, i.e. PIO_PSR resets at 1. However, in some
events, it is important that PIO lines are controlled by the peripheral (as in the case of memory chip select lines that mu st
be driven inactive after reset or for address lines that must be driven low for booting out of an external memory). Thus,
the reset value of PIO_PSR is defined at the product level, depending on the multiplexing of the device.
27.4.3 Peripheral A or B Selection
The PIO Controller provides multiplexing of up to two peripheral functions on a single pin. The selection is performed by
writing PIO_ASR (A Select Register) and PIO_BSR (Select B Register). PIO_ABSR (AB Select Status Register)
indicates which peripheral line is currently selected. For each pin, the corresponding bit at level 0 means peripheral A is
selected whereas the corresponding bit at level 1 indicates that peripheral B is selected.
Note that multiplexing of peripheral lines A and B only affects the output line. The peripheral input lines are always
connected to the pin input.
After reset, PIO_ABSR is 0, thus indicating that all the PIO lines are configured on peripheral A. However, peripheral A
generally does not drive the pin as the PIO Controller resets in I/O line mode.
Writing in PIO_ASR and PIO_BSR manages PIO_ABSR regardless of the configuration of the pin. However, assignment
of a pin to a peripheral function requires a write in the corresponding peripheral selection register (PIO_ASR or
PIO_BSR) in addition to a write in PIO_PDR.
27.4.4 Output Control
When the I/0 line is assigned to a peripheral function, i.e. the corresponding bit in PIO_PSR is at 0, the drive of the I/O
line is controlled by the peripheral. Peripheral A or B, depending on the value in PIO_ABSR, determines whether the pin
is driven or not.
When the I/O line is controlled by the PIO controller, the pin can be configured to be driven. This is done by writing
PIO_OER (Output Enable Register) and PIO_ODR (Output Disable Register). The results of these write operations are
detected in PIO_OSR (Output Status Register). When a bit in this register is at 0, the corresponding I/O line is used as an
input only. When the bit is at 1, the corresponding I/O line is driven by the PIO controller.
The level driven on an I/O line can be determined by writing in PIO_SODR (Set Output Data Register) and PIO_CODR
(Clear Output Data Register). These write operations respectively set and clear PIO_ODSR (Output Data Status
Register), which represents the data driven on the I/O lines. Writing in PIO_OER and PIO_ODR manages PIO_OSR
whether the pin is configured to be controlled by the PIO controller or assigned to a peripheral function. This enables
configuration of the I/O line prior to setting it to be managed by the PIO Controller.
Similarly, writing in PIO_SODR and PIO_CODR effects PIO_ODSR. This is important as it defines the first level driven
on the I/O line.
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27.4.5 Synchronous Data Output
Controlling all parallel busses using several PIOs requires two successive write operations in the PIO_SODR and
PIO_CODR registers. This may lead to unexpected transient values. The PIO controller offers a direct control of PIO
outputs by single write access to PIO_ODSR (Output Data Status Register). Only bits unmasked by PIO_OWSR (Output
Write Status Register) are written. The mask bits in the PIO_OWSR are set by writing to PIO_OWER (Output Write
Enable Register) and cleared by writing to PIO_OWDR (Output Write Disable Register).
After reset, the synchronous data output is disabled on all the I/O lines as PIO_OWSR resets at 0x0.
27.4.6 Multi Drive Control (Open Drain)
Each I/O can be independently programmed in Open Drain by using the Multi Drive feature. This feature permits several
drivers to be connected on the I/O line which is driven low only by each device. An external pull-up resistor (or enabling
of the internal one) is generally required to guarantee a high level on the line.
The Multi Drive feature is controlled by PIO_MDER (Multi-driver Enable Register) and PIO_MDDR (Multi-driver Disable
Register). The Multi Drive can be selected whether the I/O line is controlled by the PIO controller or assigned to a
peripheral function. PIO_MDSR (Multi-driver Status Register) indicates the pins that are configured to support external
drivers.
After reset, the Multi Drive feature is disabled on all pins, i.e. PIO_MDSR resets at value 0x0.
27.4.7 Output Line Timings
Figure 27-4 shows how the outputs are driven either by writing PIO_SODR or PIO_CODR, or by directly writing
PIO_ODSR. This last case is valid only if the corresponding bit in PIO_OWSR is set. Figure 27-4 also shows when the
feedback in PIO_PDSR is available.
Figure 27-4. Output Line Timing s
27.4.8 Inputs
The level on each I/O line can be read through PIO_PDSR (Pin Data Status Register). This register indicates the level of
the I/O lines regardless of their configuration, whether uniquely as an input or driven by the PIO controller or driven by a
peripheral.
Reading the I/O line levels requires the clock of the PIO controller to be enabled, otherwise PIO_PDSR reads the levels
present on the I/O line at the time the clock was disabled.
27.4.9 Input Glitch Filtering
Optional input glitch filters are independently programmable on each I/O line. When the glitch filter is enabled, a glitch
with a duration of less than 1/2 Master Clock (MCK) cycle is automatically rejected, while a pulse with a duration of 1
2 cycles
APB Access
2 cycles
APB Access
MCK
Write PIO_SODR
Write PIO_ODSR at 1
PIO_ODSR
PIO_PDSR
Write PIO_CODR
Write PIO_ODSR at 0
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Master Clock cycle or more is accepted. For pulse durations between 1/2 Master Clock cycle and 1 Master Clock cycle
the pulse may or may not be taken into account, depending on the precise timing of its occurrence. Thus for a pulse to be
visible it must exceed 1 Master Clock cycle, whereas for a glitch to be reliably filtered out, its duration must not exceed
1/2 Master Clock cycle. The filter introduces one Master Clock cycle latency if the pin level change occurs before a risin g
edge. However, this latency does not appear if the pin level change occurs before a falling edge. This is illustrated in
Figure 27-5.
The glitch filters are controlled by the register set; PIO_IFER (Input Filter Enable Register), PIO_IFDR (Input Filter
Disable Register) and PIO_IFSR (Input Filter Status Register). Writing PIO_IFER and PIO_IFDR respectively sets and
clears bits in PIO_IFSR. This last register enables the glitch filter on the I/O lines.
When the glitch filter is enabled, it does not modify the behavior of the inputs on the peripherals. It acts only on the value
read in PIO_PDSR and on the input change interrupt detection. The glitch filters require that the PIO Controller clock is
enabled.
Figure 27-5. Input Glitch Filter Timi ng
27.4.10 Input Change Interrupt
The PIO Controller can be programmed to generate an interrupt when it detects an input change on an I/O line. Th e Input
Change Interrupt is controlled by writing PIO_IER (Interrupt Enable Register) and PIO_IDR (Interrupt Disable Register),
which respectively enable and disable the input change interrupt by setting and clearing the corresponding bit in
PIO_IMR (Interrupt Mask Register). As Input change detection is possible only by comparing two successive samplings
of the input of the I/O line, the PIO Controller clock must be enabled. The Input Change Interrupt is available, regardless
of the configuration of the I/O line, i.e. configured as an input only, controlled by the PIO Controller or assigned to a
peripheral function.
When an input change is detected on an I/O line, the corresponding bit in PIO_ISR (Interrupt Status Register) is set. If
the corresponding bit in PIO_IMR is set, the PIO Controller interrupt line is asserted. The interrupt signals of the thirty-two
channels are ORed-wired together to generate a single interrupt signal to the Advanced Interrupt Controller.
When the software reads PIO_ISR, all the interrupts are automatically cleared. This signifies that all the interrupts that
are pending when PIO_ISR is read must be handled.
MCK
Pin Level
PIO_PDSR
if PIO_IFSR = 0
PIO_PDSR
if PIO_IFSR = 1
1 cycle 1 cycle 1 cycle
up to 1.5 cycles
2 cycles
up to 2.5 cycles up to 2 cycles
1 cycle
1 cycle
225
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 27-6. Input Cha nge Interrupt Timings
MCK
Pin Level
Read PIO_ISR APB Access
PIO_ISR
APB Access
226
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.5 I/O Lines Programming Example
The programing example as shown in Table 27-1 below is used to define the following configuration.
4-bit output port on I/O lines 0 to 3, (should be written in a single write operation), open-drain, with pull-up resistor
Four output signals on I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no pull-up resistor
Four input signals on I/O lines 8 to 11 (to read push-button states for example), with pull-up resistors, glitch filters
and input change interrupts
Four input signals on I/O line 12 to 15 to read an external device status (polled, thus no input change interrupt), no
pull-up resistor, no glitch filter
I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor
I/O lines 20 to 23 assigned to peripheral B functions, no pull-up resistor
I/O line 24 to 27 assigned to peripheral A with Input Change Interrupt and pull-up resistor
Table 27-1 . Programming Examp le
Register Value to be Written
PIO_PER 0x0000 FFFF
PIO_PDR 0x0FFF 0000
PIO_OER 0x0000 00FF
PIO_ODR 0x0FFF FF00
PIO_IFER 0x0000 0F00
PIO_IFDR 0x0FFF F0FF
PIO_SODR 0x0000 0000
PIO_CODR 0x0FFF FFFF
PIO_IER 0x0F00 0F00
PIO_IDR 0x00FF F0FF
PIO_MDER 0x0000 000F
PIO_MDDR 0x0FFF FFF0
PIO_PUDR 0x00F0 00F0
PIO_PUER 0x0F0F FF0F
PIO_ASR 0x0F0F 0000
PIO_BSR 0x00F0 0000
PIO_OWER 0x0000 000F
PIO_OWDR 0x0FFF FFF0
227
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6 Parallel Input/Output Controller (PIO) User Interface
Each I/O line controlled by the PIO Controller is associated with a bit in each of the PIO Controller User Interface
registers. Each register is 32 bits wide. If a parallel I/O line is not defined, writing to the corresponding bits has no effect.
Undefined bits read zero. If the I/O line is not multiplexed with any peripheral, the I/O line is controlled by the PIO
Controller and PIO_PSR returns 1 systematically.
Table 27-2. Regist er Mapping
Offset Register Name Access Reset
0x0000 PIO Enable Register PIO_PER Write-only –
0x0004 PIO Disable Register PIO_PDR Write-only –
0x0008 PIO Status Register PIO_PSR Read-only (1)
0x000C Reserved
0x0010 Output Enable Register PIO_OER Write-only –
0x0014 Output Disable Register PIO_ODR Write-only –
0x0018 Output Status Register PIO_OSR Read-only 0x0000 0000
0x001C Reserved
0x0020 Glitch Input Filter Enable Register PIO_IFER Write-only –
0x0024 Glitch Input Filter Disable Register PIO_IFDR Write-only –
0x0028 Glitch Input Filter Status Register PIO_IFSR Read-only 0x0000 0000
0x002C Reserved
0x0030 Set Output Data Register PIO_SODR Write-only –
0x0034 Clear Output Data Register PIO_CODR Write-only
0x0038 Output Data Status Register PIO_ODSR Read-only
or(2)
Read-write –
0x003C Pin Data Status Register PIO_PDSR Read-only (3)
0x0040 Interrupt Enable Register PIO_IER Write-only –
0x0044 Interrupt Disable Register PIO_IDR Write-only –
0x0048 Interrupt Mask Register PIO_IMR Read-only 0x00000000
0x004C Interrupt Status Register(4) PIO_ISR Read-only 0x00000000
0x0050 Multi-driver Enable Register PIO_MDER Write-only –
0x0054 Multi-driver Disable Register PIO_MDDR Write-only –
0x0058 Multi-driver Status Register PIO_MDSR Read-only 0x00000000
0x005C Reserved
0x0060 Pull-up Disable Register PIO_PUDR Write-only –
0x0064 Pull-up Enable Register PIO_PUER Write-only –
0x0068 Pad Pull-up Status Register PIO_PUSR Read-only 0x00000000
0x006C Reserved
228
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Notes: 1. Reset value of PIO_PSR depends on the product implementation.
2. PIO_ODSR is Read-only or Read-write depending on PIO_OWSR I/O lines.
3. Reset value of PIO_PDSR depends on the level of the I/O lines. Reading the I/O line levels requires the clock of the
PIO Controller to be enabled, otherwise PIO_PDSR reads the levels present on the I/O line at the time the clock was
disabled.
4. PIO_ISR is reset at 0x0. However , the first read of the register may read a different value as input changes may have
occurred.
5. Only this set of registers clears the status by writing 1 in the first register and sets the status by writing 1 in the second
register.
0x0070 Peripheral A Select Register (5) PIO_ASR Write-only –
0x0074 Peripheral B Select Register(5) PIO_BSR Write-only –
0x0078 AB Status Register(5) PIO_ABSR Read-only 0x00000000
0x007C
to
0x009C Reserved
0x00A0 Output Write Enable PIO_OWER Write-only –
0x00A4 Output Write Disable PIO_OWDR Write-only –
0x00A8 Output Write Status Register PIO_OWSR Read-only 0x00000000
0x00AC Reserved
Table 27-2. Regist er Mapping (Continued)
Offset Register Name Access Reset
229
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.1 PIO Controller PIO Enable Register
Name: PIO_PER
Access Type: Write-only
• P0-P31: PIO Enable
0 = No effect.
1 = Enables the PIO to control the corresponding pin (disables peripheral control of the pin).
27.6.2 PIO Controller PIO Disable Register
Name: PIO_PDR
Access Type: Write-only
• P0-P31: PIO Disable
0 = No effect.
1 = Disables the PIO from controlling the corresponding pin (enables peripheral control of the pin).
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
230
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.3 PIO Controller PIO Status Register
Name: PIO_PSR
Access Type: Read-only
• P0-P31: PIO Status
0 = PIO is inactive on the corresponding I/O line (peripheral is active).
1 = PIO is active on the corresponding I/O line (peripheral is inactive).
27.6.4 PIO Controller Output Enable Register
Name: PIO_OER
Access Type: Write-only
• P0-P31: Output Enable
0 = No effect.
1 = Enables the output on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
231
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.5 PIO Controller Output Disable Register
Name: PIO_ODR
Access Type: Write-only
• P0-P31: Output Disable
0 = No effect.
1 = Disables the output on the I/O line.
27.6.6 PIO Controller Output Status Register
Name: PIO_OSR
Access Type: Read-only
• P0-P31: Output Status
0 = The I/O line is a pure input.
1 = The I/O line is enabled in output.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
232
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.7 PIO Controller Input Filter Enable Register
Name: PIO_IFER
Access Type: Write-only
• P0-P31: Input Filter Enable
0 = No effect.
1 = Enables the input glitch filter on the I/O line.
27.6.8 PIO Controller Input Filter Disable Register
Name: PIO_IFDR
Access Type: Write-only
• P0-P31: Input Filter Disable
0 = No effect.
1 = Disables the input glitch filter on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
233
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.9 PIO Controller Input Filter Status Register
Name: PIO_IFSR
Access Type: Read-only
• P0-P31: Input Filer Status
0 = The input glitch filter is disabled on the I/O line.
1 = The input glitch filter is enabled on the I/O line.
27.6.10 PIO Controller Set Output Data Register
Name: PIO_SODR
Access Type: Write-only
• P0-P31: Set Output Data
0 = No effect.
1 = Sets the data to be driven on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
234
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.11 PIO Controller Clear Output Data Register
Name: PIO_CODR
Access Type: Write-only
• P0-P31: Set Output Data
0 = No effect.
1 = Clears the data to be driven on the I/O line.
27.6.12 PIO Controller Output Data Status Register
Name: PIO_ODSR
Access Type: Read-only or Read-write
• P0-P31: Output Da ta Status
0 = The data to be driven on the I/O line is 0.
1 = The data to be driven on the I/O line is 1.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
235
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.13 PIO Controller Pin Data Status Register
Name: PIO_PDSR
Access Type: Read-only
• P0-P31: Output Da ta Status
0 = The I/O line is at level 0.
1 = The I/O line is at level 1.
27.6.14 PIO Controller Interrupt Enable Register
Name: PIO_IER
Access Type: Write-only
• P0-P31: Input Change Interrupt Enable
0 = No effect.
1 = Enables the Input Change Interrupt on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
236
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.15 PIO Controller Interrupt Disable Register
Name: PIO_IDR
Access Type: Write-only
• P0-P31: Input Change Interrupt Disable
0 = No effect.
1 = Disables the Input Change Interrupt on the I/O line.
27.6.16 PIO Controller Interrupt Mask Register
Name: PIO_IMR
Access Type: Read-only
• P0-P31: Input Change Interrupt Mask
0 = Input Change Interrupt is disabled on the I/O line.
1 = Input Change Interrupt is enabled on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
237
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.17 PIO Controller Interrupt Status Register
Name: PIO_ISR
Access Type: Read-only
• P0-P31: Input Change Interrupt Status
0 = No Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
1 = At least one Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
27.6.18 PIO Multi-driver Enable Register
Name: PIO_MDER
Access Type: Write-only
• P0-P31: Multi Drive Enable.
0 = No effect.
1 = Enables Multi Drive on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
238
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.19 PIO Multi-driver Disable Register
Name: PIO_MDDR
Access Type: Write-only
• P0-P31: Multi Drive Disable.
0 = No effect.
1 = Disables Multi Drive on the I/O line.
27.6.20 PIO Multi-driver Status Regis t er
Name: PIO_MDSR
Access Type: Read-only
• P0-P31: Multi Drive Status.
0 = The Multi Drive is disabled on the I/O line. The pin is driven at high and low level.
1 = The Multi Drive is enabled on the I/O line. The pin is driven at low level only.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
239
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.21 PIO Pull Up Disable Register
Name: PIO_PUDR
Access Type: Write-only
• P0-P31: Pull Up Disable.
0 = No effect.
1 = Disables the pull up resistor on the I/O line.
27.6.22 PIO Pull Up Enable Register
Name: PIO_PUER
Access Type: Write-only
• P0-P31: Pull Up Enable.
0 = No effect.
1 = Enables the pull up resistor on the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
240
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.23 PIO Pull Up Status Register
Name: PIO_PUSR
Access Type: Read-only
• P0-P31: Pull Up Status.
0 = Pull Up resistor is enabled on the I/O line.
1 = Pull Up resistor is disabled on the I/O line.
27.6.24 PIO Peripheral A Select Register
Name: PIO_ASR
Access Type: Write-only
• P0-P31: Peripheral A Select.
0 = No effect.
1 = Assigns the I/O line to the Peripheral A function.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
241
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.25 PIO Peripheral B Select Register
Name: PIO_BSR
Access Type: Write-only
• P0-P31: Peripheral B Select.
0 = No effect.
1 = Assigns the I/O line to the peripheral B function.
27.6.26 PIO Peripheral A B Status Register
Name: PIO_ABSR
Access Type: Read-only
• P0-P31: Peripheral A B Status.
0 = The I/O line is assigned to the Peripheral A.
1 = The I/O line is assigned to the Peripheral B.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
242
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.27 PIO Output Write Enable Register
Name: PIO_OWER
Access Type: Write-only
• P0-P31: Output Write Enable.
0 = No effect.
1 = Enables writing PIO_ODSR for the I/O line.
27.6.28 PIO Output Write Disable Register
Name: PIO_OWDR
Access Type: Write-only
• P0-P31: Output Write Disable.
0 = No effect.
1 = Disables writing PIO_ODSR for the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
243
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
27.6.29 PIO Output Write Status Register
Name: PIO_OWSR
Access Type: Read-only
• P0-P31: Output Write Status.
0 = Writing PIO_ODSR does not affect the I/O line.
1 = Writing PIO_ODSR affects the I/O line.
31 30 29 28 27 26 25 24
P31 P30 P29 P28 P27 P26 P25 P24
23 22 21 20 19 18 17 16
P23 P22 P21 P20 P19 P18 P17 P16
15 14 13 12 11 10 9 8
P15 P14 P13 P12 P11 P10 P9 P8
76543210
P7 P6 P5 P4 P3 P2 P1 P0
244
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
28. Serial Peripheral Interface (SPI)
28.1 Overview
The Serial Peripheral Interface (SPI) circuit is a synchronous serial data link that provides communication with external
devices in Master or Slave Mode. It also enables communication between processors if an external processor is
connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to other SPIs. During a data
transfer, one SPI system acts as the “master”' which controls the data flow, while the other devices act as “slaves” which
have data shifted into and out by the master. Different CPUs can take turn being masters (Multiple Master Protocol
opposite to Single Master Protocol where one CPU is always the master while all of the others are always slaves) and
one master may simultaneously shift data into multiple slaves. However, only one slave may drive its output to write data
back to the master at any given time.
A slave device is selected when the master asserts its NSS signal. If multiple slave devices exist, the master generates a
separate slave select signal for each slave (NPCS).
The SPI system consists of two data lines and two control lines:
Master Out Slave In (MOSI): This data line supplies the output data from the master shifted into the input(s) of the
slave(s).
Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master. There
may be no more than one slave transmitting data during any particular transfer.
Serial Clock (SPCK): This control line is driven by the master and regulates the flow of the data bits. The master
may transmit data at a variety of baud rates; the SPCK line cycles once for each bit that is transmitted.
Slave Select (NSS): This control line allows slaves to be turned on and off by hardware.
28.2 Block Diagram
Figure 28-1. Block Diagram
SPI Interface
Interrupt Control
PIO
PDC
PMC MCK
SPI Interrupt
SPCK
MISO
MOSI
NPCS0/NSS
NPCS1
NPCS2
NPCS3
APB
245
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
28.3 Application Block Diagram
Figure 28-2. Application Block Diagram: Single Master/Multiple Slave Implementation
28.4 Signal Description
SPI Master
SPCK
MISO
MOSI
NPCS0
NPCS1
NPCS2
SPCK
MISO
MOSI
NSS
Slave 0
SPCK
MISO
MOSI
NSS
Slave 1
SPCK
MISO
MOSI
NSS
Slave 2
NC
NPCS3
Table 28-1. Signal Descriptio n
Pin Name Pin Description
Type
Master Slave
MISO Master In Slave Out Input Output
MOSI Master Out Slave In Output Input
SPCK Serial Clock Output Input
NPCS1-NPCS3 Peripheral Chip Selects Output Unused
NPCS0/NSS Peripheral Chip Select/Slave Select Output Input
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28.5 Product Dependencies
28.5.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer must
first program the PIO controllers to assign the SPI pins to their peripheral functions.
28.5.2 Power Management
The SPI may be clocked through the Power Management Controller (PMC), thus the programmer must first configure the
PMC to enable the SPI clock.
28.5.3 Interrupt
The SPI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling the SPI interrupt
requires programming the AIC before configuring the SPI.
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28.6 Functional Description
28.6.1 Modes of Operation
The SPI operates in Master Mode or in Slave Mode.
Operation in Master Mode is programmed by writing at 1 the MSTR bit in the Mode Register. The pins NPCS0 to NPCS3
are all configured as outputs, the SPCK pin is driven, the MISO line is wired on the receiver input and the MOSI line
driven as an output by the transmitter.
If the MSTR bit is written at 0, the SPI operates in Slave Mode. The MISO line is driven by the transmitter output, the
MOSI line is wired on the receiver input, the SPCK pin is driven by the transmitter to synchronize the receiver. The
NPCS0 pin becomes an input, and is used as a Slave Select signal (NSS). The pins NPCS1 to NPCS3 are not driven
and can be used for other purposes.
The data transfers are identically programmable for both modes of operations. The baud rate generator is activated only
in Master Mode.
28.6.2 Data Transfer
Four combinations of polarity and phase are available for data transfers. The clock polarity is programmed with the CPOL
bit in the Chip Select Register. The clock phase is programmed with the NCPHA bit. These two parameters determine
the edges of the clock signal on which data is driven and sampled. Each of the two parameters has two possible states,
resulting in four possible combinations that are incompatible with one another. Thus, a master/slave pair must use the
same parameter pair values to communicate. If multiple slaves are used and fixed in different configurations, the master
must reconfigure itself each time it needs to communicate with a different slave.
Table 28-2 shows the four modes and corresponding parameter settings.
Figure 28-3 and Figure 28-4 show examples of data transfers.
Table 28-2. SPI Bus Protocol Mode
SPI Mode CPOL NCPHA
001
100
211
310
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Figure 28-3. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)
Figure 28-4. SPI T ransfer Format (NCPHA = 0, 8 bits per transfer)
6
*
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MISO
(from slave)
NSS
(to slave)
SPCK cycle (for reference)
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
2
2
1
1
* Not defined, but normally MSB of previous character received.
1 2345 786
*
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
1 2345 7
MOSI
(from master)
MISO
(from slave)
NSS
(to slave)
SPCK cycle (for reference) 8
MSB
MSB
LSB
LSB
6
6
5
5
4
4
3
3
1
1
* Not defined but normally LSB of previous character transmitted.
2
2
6
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28.6.3 Master Mode Operations
When configured in Master Mode, the SPI operates on the clock generated by the internal programmable baud rate
generator. It fully controls the data transfers to and from the slave(s) connected to the SPI bus. The SPI drives the chip
select line to the slave and the serial clock signal (SPCK).
The SPI features two holding registers, the Transmit Data Register and the Receive Data Register, and a single Shift
Register. The holding registers maintain the data flow at a constant rate.
After enabling the SPI, a data transfer begins when the processor writes to the SPI_TDR (Transmit Data Register). The
written data is immediately transferred in the Shift Register and transfer on the SPI bus starts. While the data in the Shift
Register is shifted on the MOSI line, the MISO line is sampled and shifted in the Shift Register. Transmission cannot
occur without reception.
Before writing the TDR, the PCS field must be set in order to select a slave.
If new data is written in SPI_TDR during the transfer, it stays in it until the current transfer is completed. Then, the
received data is transferred from the Shift Register to SPI_RDR, the data in SPI_TDR is loaded in the Shift Register and
a new transfer starts.
The transfer of a data written in SPI_TDR in the Shift Register is indicated by the TDRE bit (Transmit Data Register
Empty) in the Status Register (SPI_SR). When new data is written in SPI_TDR, this bit is cleared. The TDRE bit is used
to trigger the Transmit PDC channel.
The end of transfer is indicated by the TXEMPTY flag in the SPI_SR register. If a transfer delay (DLYBCT) is greater than
0 for the last transfer, TXEMPTY is set after the completion of said delay. The master clock (MCK) can be switched off at
this time.
The transfer of received data from the Shift Register in SPI_RDR is indicated by the RDRF bit (Receive Data Register
Full) in the Status Register (SPI_SR). When the received data is read, the RDRF bit is cleared.
If the SPI_RDR (Receive Data Register) has not been read before new data is received, the Overrun Error bit (OVRES)
in SPI_SR is set. As long as this flag is set, data is loaded in SPI_RDR. The user has to read the status register to clear
the OVRES bit.
Figure 28-5 on page 250 shows a block diagram of the SPI when operating in Master Mode. Figure 28-6 on page 251
shows a flow chart describing how transfers are handled.
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28.6.3.1 Master Mode Block Diagram
Figure 28-5. Master Mode Block Diagram
Shift Register
SPCK
MOSI
LSB MSB
MISO
SPI_RDR RD
SPI
Clock
TDRE
SPI_TDR TD
RDRF
OVRES
SPI_CSR0..3
CPOL
NCPHA
BITS
MCK Baud Rate Generator
SPI_CSR0..3
SCBR
NPCS3
NPCS0
NPCS2
NPCS1
NPCS0
0
1
PS
SPI_MR PCS
SPI_TDR PCS
MODF
Current
Peripheral
SPI_RDR PCS
SPI_CSR0..3
CSAAT
PCSDEC
MODFDIS
MSTR
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28.6.3.2 Master Mode Flow Diagram
Figure 28-6. M aster Mode Flow Diagram S
SPI Enable
CSAAT ?
PS ?
1
0
0
1
1
NPCS = SPI_TDR(PCS) NPCS = SPI_MR(PCS)
Delay DLYBS
Serializer = SPI_TDR(TD)
TDRE = 1
Data Transfer
SPI_RDR(RD) = Serializer
RDRF = 1
TDRE ?
NPCS = 0xF
Delay DLYBCS
Fixed
peripheral
Variable
peripheral
Delay DLYBCT
0
1CSAAT ?
0
TDRE ? 1
0
PS ? 0
1
SPI_TDR(PCS)
= NPCS ?
no
yes SPI_MR(PCS)
= NPCS ?
no
NPCS = 0xF
Delay DLYBCS
NPCS = SPI_TDR(PCS)
NPCS = 0xF
Delay DLYBCS
NPCS = SPI_MR(PCS),
SPI_TDR(PCS)
Fixed
peripheral
Variable
peripheral
- NPCS defines the current Chip Select
- CSAAT, DLYBS, DLYBCT refer to the fields of the
Chip Select Register corresponding to the Current Chip Select
- When NPCS is 0xF, CSAAT is 0.
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28.6.3.3 Clock Generation
The SPI Baud rate clock is generated by dividing the Master Clock (MCK), by a value between 1 and 255.
This allows a maximum operating baud rate at up to Master Clock and a minimum operating baud rate of MCK divided by
255.
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.
The divisor can be defined independently for each chip select, as it has to be programmed in the SCBR field of the Chip
Select Registers. This allows the SPI to automatically adapt the baud rate for each interfaced peripheral without
reprogramming.
28.6.3.4 Transfer Delays
Figure 28-7 shows a chip select transfer change and consecutive transfers on the same chip select. Three delays can be
programmed to modify the transfer waveforms:
The delay between chip selects, programmable only once for all the chip selects by writing the DLYBCS field in the
Mode Register. Allows insertion of a delay between release of one chip select and before assertion of a new one.
The delay before SPCK, independently programmable for each chip select by writing the field DLYBS. Allows the
start of SPCK to be delayed after the chip select has been asserted.
The delay between consecutive transfers, independently programmable for each chip select by writing the
DLYBCT field. Allows insertion of a delay between two transfers occurring on the same chip select
These delays allow the SPI to be adapted to the interfaced peripherals and their speed and bus release time.
Figure 28-7. Programmable Delays
28.6.3.5 Peripheral Selection
The serial peripherals are selected through the assertion of the NPCS0 to NPCS3 signals. By default, all the NPCS
signals are high before and after each transfer.
The peripheral selection can be performed in two different ways:
Fixed Peripheral Select: SPI exchanges data with only one peripheral
Variable Peripheral Select: Data can be exchanged with more than one peripheral
Fixed Peripheral Select is activated by writing the PS bit to zero in SPI_MR (Mode Register). In this case, the current
peripheral is defined by the PCS field in SPI_MR and the PCS field in the SPI_TDR has no effect.
Variable Peripheral Select is activated by setting PS bit to one. The PCS field in SPI_TDR is used to select the current
peripheral. This means that the peripheral selection can be defined for each new data.
The Fixed Peripheral Selection allows buffer transfers with a single peripheral. Using the PDC is an optimal means, as
the size of the data transfer between the memory and the SPI is either 8 bits or 16 bits. However, changing the peripheral
selection requires the Mode Register to be reprogrammed.
DLYBCS DLYBS DLYBCT DLYBCT
Chip Select 1
Chip Select 2
SPCK
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The Variable Peripheral Selection allows buffer transfers with multiple peripherals without reprogramming the Mode
Register. Data written in SPI_TDR is 32 bits wide and defines the real data to be transmitted and the peripheral it is
destined to. Using the PDC in this mode requires 32-bit wide buffers, with the data in the LSBs and the PCS and
LASTXFER fields in the MSBs, however the SPI still controls the number of bits (8 to16) to be transferred through MISO
and MOSI lines with the chip select configuration registers. This is not the optimal means in term of memory size for the
buffers, but it provides a very effective means to exchange data with several peripherals without any intervention of the
processor.
28.6.3.6 Peripheral Chip Select Decoding
The user can program the SPI to operate with up to 15 peripherals by decoding the four Chip Select lines, NPCS0 to
NPCS3 with an external logic. This can be enabled by writing the PCSDEC bit at 1 in the Mode Register (SPI_MR).
When operating without decoding, the SPI makes sure that in any case only one chip select line is activated, i.e. driven
low at a time. If two bits are defined low in a PCS field, only the lowest numbered chip select is driven low.
When operating with decoding, the SPI directly outputs the value defined by the PCS field of either the Mode Register or
the Transmit Data Register (depending on PS).
As the SPI sets a default value of 0xF on the chip select lines (i.e. all chip select lines at 1) when not processing any
transfer, only 15 peripherals can be decoded.
The SPI has only four Chip Select Registers, not 15. As a result, when decoding is activated, each chip select defines the
characteristics of up to four peripherals. As an example, SPI_CRS0 defines the characteristics of the externally decoded
peripherals 0 to 3, corresponding to the PCS values 0x0 to 0x3. Thus, the user has to make sure to connect compatible
peripherals on the decoded chip select lines 0 to 3, 4 to 7, 8 to 11 and 12 to 14.
28.6.3.7 Peripheral Deselection
When operating normally, as soon as the transfer of the last data written in SPI_TDR is completed, the NPCS lines all
rise. This might lead to runtime error if the processor is too long in responding to an interrupt, and thus might lead to
difficulties for interfacing with some serial peripherals requiring the chip select line to remain active during a full set of
transfers.
To facilitate interfacing with such devices, the Chip Select Register can be programmed with the CSAAT bit (Chip Select
Active After Transfer) at 1. This allows the chip select lines to remain in their current state (low = active) until transfer to
another peripheral is required.
Figure 28-8 shows different peripheral deselection cases and the effect of the CSAAT bit.
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Figure 28-8. Peripheral Deselection
28.6.3.8 Mode Fault Detection
A mode fault is detected when the SPI is programmed in Master Mode and a low level is driven by an external master on
the NPCS0/NSS signal. NPCS0, MOSI, MISO and SPCK must be configured in open drain through the PIO controller, so
that external pull up resistors are needed to guarantee high level.
When a mode fault is detected, the MODF bit in the SPI_SR is set until the SPI_SR is read and the SPI is automatically
disabled until re-enabled by writing the SPIEN bit in the SPI_CR (Control Register) at 1.
By default, the Mode Fault detection circuitry is enabled. The user can disable Mode Fault detection by setting the
MODFDIS bit in the SPI Mode Register (SPI_MR).
28.6.4 SPI Slave Mode
When operating in Slave Mode, the SPI processes data bits on the clock provided on the SPI clock pin (SPCK).
The SPI waits for NSS to go active before receiving the serial clock from an external master. When NSS falls, the clock is
validated on the serializer, which processes the number of bits defined by the BITS field of the Chip Select Register 0
(SPI_CSR0). These bits are processed following a phase and a polarity defined respectively by the NCPHA and CPOL
bits of the SPI_CSR0. Note that BITS, CPOL and NCPHA of the other Chip Select Registers have no effect when the SPI
is programmed in Slave Mode.
The bits are shifted out on the MISO line and sampled on the MOSI line.
When all the bits are processed, the received data is transferred in the Receive Data Register and the RDRF bit rises. If
the SPI_RDR (Receive Data Register) has not been read before new data is received, the Overrun Error bit (OVRES) in
A
NPCS[0..3]
Write SPI_TDR
TDRE
NPCS[0..3]
Write SPI_TDR
TDRE
NPCS[0..3]
Write SPI_TDR
TDRE
DLYBCS
PCS = A
DLYBCS
DLYBCT
A
PCS = B
B
DLYBCS
PCS = A
DLYBCS
DLYBCT
A
PCS = B
B
DLYBCS
DLYBCT
PCS=A
ADLYBCS
DLYBCT
A
PCS = A
AA
DLYBCT
AA
CSAAT = 0
DLYBCT
AA
CSAAT = 1
A
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SPI_SR is set. As long as this flag is set, data is loaded in SPI_RDR. The user has to read the status register to clear the
OVRES bit.
When a transfer starts, the data shifted out is the data present in the Shift Register. If no data has been written in the
Transmit Data Register (SPI_TDR), the last data received is transferred. If no data has been received since the last
reset, all bits are transmitted low, as the Shift Register resets at 0.
When a first data is written in SPI_TDR, it is transferred immediately in the Shift Register and the TDRE bit rises. If new
data is written, it remains in SPI_TDR until a transfer occurs, i.e. NSS falls and there is a valid clock on the SPCK pin.
When the transfer occurs, the last data written in SPI_TDR is transferred in the Shift Register and the TDRE bit rises.
This enables frequent updates of critical variables with single transfers.
Then, new data is loaded in the Shift Register from the Transmit Data Register. In case no character is ready to be
transmitted, i.e. no character has been written in SPI_TDR since the last load from SPI_TDR to the Shift Register, the
Shift Register is not modified and the last received character is retransmitted.
Figure 28-9 shows a block diagram of the SPI when operating in Slave Mode.
Figure 28-9. Slave Mode Functional Block Diagram
Shift Register
SPCK
SPIENS
LSB MSB
NSS
MOSI
SPI_RDR RD
SPI
Clock
TDRE
SPI_TDR TD
RDRF
OVRES
SPI_CSR0
CPOL
NCPHA
BITS
SPIEN
SPIDIS
MISO
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28.7 Serial Peripheral Interface (SPI) User Interface
Table 28-3. Register Mapping
Offset Register Name Access Reset
0x00 Control Register SPI_CR Write-only ---
0x04 Mode Register SPI_MR Read-write 0x0
0x08 Re ceive Data Register SPI_RDR Read-only 0x0
0x0C Transmit Data Register SPI_TDR Write-only ---
0x10 Status Register SPI_SR Read-only 0x000000F0
0x14 Interrupt Enable Register SPI_IER Write-only ---
0x18 Interrupt Disable Register SPI_IDR Write-only ---
0x1C Interrupt Mask Register SPI_IMR Read-only 0x0
0x20 - 0x2C Reserved
0x30 Chip Select Register 0 SPI_CSR0 Read-write 0x0
0x34 Chip Select Register 1 SPI_CSR1 Read-write 0x0
0x38 Chip Select Register 2 SPI_CSR2 Read-write 0x0
0x3C Chip Select Register 3 SPI_CSR3 Read-write 0x0
0x004C - 0x00F8 Reserved – – –
0x004C - 0x00FC Reserved – – –
0x100 - 0x124 Reserved for the PDC
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28.7.1 SPI Control Register
Name: SPI_CR
Access Type: Write-only
• SPIEN: SPI Enable
0 = No effect.
1 = Enables the SPI to transfer and receive data.
• SPIDIS: SPI Disable
0 = No effect.
1 = Disables the SPI.
As soon as SPIDIS is set, SPI finishes its transfer.
All pins are set in input mode and no data is received or transmitted.
If a transfer is in progress, the transfer is finished before the SPI is disabled.
If both SPIEN and SPIDIS are equal to one when the control register is written, the SPI is disabled.
• SWRST: SPI Software Reset
0 = No effect.
1 = Reset the SPI. A software-triggered hardware reset of the SPI interface is performed.
The SPI is in slave mode after software reset.
PDC channels are not affected by software reset.
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this allows
to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD transfer has
completed.
31 30 29 28 27 26 25 24
–––––––LASTXFER
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SWRST–––––SPIDISSPIEN
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28.7.2 SPI Mode Register
Name: SPI_MR
Access Type: Read-write
• MSTR: Master/Slave Mode
0 = SPI is in Slave mode.
1 = SPI is in Master mode.
• PS: Peripheral Select
0 = Fixed Peripheral Select.
1 = Variable Peripheral Select.
• PCSDEC: Chip Select Decode
0 = The chip selects are directly connected to a peripheral device.
1 = The four chip select lines are connected to a 4- to 16-bit decoder.
When PCSDEC equals one, up to 15 Chip Select signals can be generated with the four lines using an external 4- to 16-bit
decoder. The Chip Select Registers define the characteristics of the 15 chip selects according to the following rules:
SPI_CSR0 defines peripheral chip select signals 0 to 3.
SPI_CSR1 defines peripheral chip select signals 4 to 7.
SPI_CSR2 defines peripheral chip select signals 8 to 11.
SPI_CSR3 defines peripheral chip select signals 12 to 14.
• MODFDIS: Mode Fault Detection
0 = Mode fault detection is enabled.
1 = Mode fault detection is disabled.
• LLB: Local Loopback Enable
0 = Local loopback path disabled.
1 = Local loopback path enabled.
LLB controls the local loopback on the data serializer for testing in Master Mode only. (MISO is internally connected on MOSI.)
• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
If PCSDEC = 0:
PCS = xxx0 NPCS[3:0] = 1110
PCS = xx01 NPCS[3:0] = 1101
31 30 29 28 27 26 25 24
DLYBCS
23 22 21 20 19 18 17 16
–––– PCS
15 14 13 12 11 10 9 8
––––––––
76543210
LLB – – MODFDIS PCSDEC PS MSTR
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PCS = x011 NPCS[3:0] = 1011
PCS = 0111 NPCS[3:0] = 0111
PCS = 1111 forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS.
• DLYBCS: Delay Between Chip Select s
This field defines the delay from NPCS inactive to the activation of another NPCS. The DLYBCS time guarantees non-overlap-
ping chip selects and solves bus contentions in case of peripherals having long data float times.
If DLYBCS is less than or equal to six, six MCK periods will be inserted by default.
Otherwise, the following equation determines the delay:
Delay Between Chip Selects DLYBCS
MCK
-----------------------
=
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28.7.3 SPI Receive Data Register
Name: SPI_RDR
Access Type: Read-only
• RD: Receive Data
Data received by the SPI Interface is stored in this register right-justified. Unused bits read zero.
• PCS: Peripheral Chip Select
In Master Mode only, these bits indicate the value on the NPCS pins at the end of a transfer. Otherwise, these bits read zero.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––– PCS
15 14 13 12 11 10 9 8
RD
76543210
RD
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28.7.4 SPI Transmit Data Register
Name: SPI_TDR
Access Type: Write-only
• TD: Transmit Data
Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the transmit
data register in a right-justified format.
PCS: Peripheral Chip Select
This field is only used if Variable Peripheral Select is active (PS = 1).
If PCSDEC = 0:
PCS = xxx0 NPCS[3:0] = 1110
PCS = xx01 NPCS[3:0] = 1101
PCS = x011 NPCS[3:0] = 1011
PCS = 0111 NPCS[3:0] = 0111
PCS = 1111 forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this allows
to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD transfer has
completed.
This field is only used if Variable Peripheral Select is active (PS = 1).
31 30 29 28 27 26 25 24
–––––––LASTXFER
23 22 21 20 19 18 17 16
–––– PCS
15 14 13 12 11 10 9 8
TD
76543210
TD
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28.7.5 SPI Status Register
Name: SPI_SR
Access Type: Read-only
• RDRF: Receive Data Register Full
0 = No data has been received since the last read of SPI_RDR
1 = Data has been received and the received data has been transferred from the serializer to SPI_RDR since the last read of
SPI_RDR.
• TDRE: Transmit Data Register Empty
0 = Data has been written to SPI_TDR and not yet transferred to the serializer.
1 = The last data written in the Transmit Data Register has been transferred to the serializer.
TDRE equals zero when the SPI is disabled or at reset. The SPI enable command sets this bit to one.
• MODF: Mode Fault Error
0 = No Mode Fault has been detected since the last read of SPI_SR.
1 = A Mode Fault occurred since the last read of the SPI_SR.
• OVRES: Overrun Error Status
0 = No overrun has been detected since the last read of SPI_SR.
1 = An overrun has occurred since the last read of SPI_SR.
An overrun occurs when SPI_RDR is loaded at least twice from the serializer since the last read of the SPI_RDR.
• ENDRX: End of RX buffer
0 = The Receive Counter Register has not reached 0 since the last write in SPI_RCR(1) or SPI_RNCR(1).
1 = The Receive Counter Register has reached 0 since the last write in SPI_RCR(1) or SPI_RNCR(1).
• ENDTX: End of TX buffer
0 = The Transmit Counter Register has not reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).
1 = The Transmit Counter Register has reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).
• RXBUFF: RX Buffer Full
0 = SPI_RCR(1) or SPI_RNCR(1) has a value other than 0.
1 = Both SPI_RCR(1) and SPI_RNCR(1) have a value of 0.
• TXBUFE: TX Buffer Empty
0 = SPI_TCR(1) or SPI_TNCR(1) has a value other than 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––––SPIENS
15 14 13 12 11 10 9 8
––––––TXEMPTYNSSR
76543210
TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF
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1 = Both SPI_TCR(1) and SPI_TNCR(1) have a value of 0.
• NSSR: NSS Rising
0 = No rising edge detected on NSS pin since last read.
1 = A rising edge occurred on NSS pin since last read.
• TXEMPTY: Transmission Re gisters Empty
0 = As soon as data is written in SPI_TDR.
1 = SPI_TDR and internal shifter are empty. If a transfer delay has been defined, TXEMPTY is set after the completion of such
delay.
• SPIENS: SPI Enable Status
0 = SPI is disabled.
1 = SPI is enabled.
Note: 1. SPI_RCR, SPI_RNCR, SPI_TCR, SPI_TNCR are physically located in the PDC.
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28.7.6 SPI Interrupt Enable Register
Name: SPI_IER
Access Type: Write-only
• RDRF: Receive Data Register Full Interrupt Enable
• TDRE: SPI Transmit Data Register Empty Interrupt Enable
• MODF: Mode Fault Err or Interrupt Enable
• OVRES: Overrun Error Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• ENDTX: End of Transmit Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
• TXBUFE: Transmit Buffer Empty Interrupt Enable
• TXEMPTY: Transmission Registers Empty Enable
• NSSR: NSS Rising Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––TXEMPTYNSSR
76543210
TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF
265
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28.7.7 SPI Interrupt Disable Register
Name: SPI_IDR
Access Type: Write-only
• RDRF: Receive Data Register Full Interrupt Disable
• TDRE: SPI Transmit Data Register Empty Interrupt Disable
• MODF: Mode Fault Err or Interrupt Disable
• OVRES: Overrun Error Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• ENDTX: End of Transmit Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
• TXBUFE: Transmit Buffer Empty Interrupt Disable
• TXEMPTY: Transmission Registers Empty Disable
• NSSR: NSS Rising Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––TXEMPTYNSSR
76543210
TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF
266
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28.7.8 SPI Interrupt Mask Register
Name: SPI_IMR
Access Type: Read-only
• RDRF: Receive Data Register Full Interrupt Mask
• TDRE: SPI Transmit Data Register Empty Interrupt Mask
• MODF: Mode Fault Err or Interrupt Mask
• OVRES: Overrun Error Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• ENDTX: End of Transmit Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
• TXBUFE: Transmit Buffer Empty Interrupt Mask
• TXEMPTY: Transmission Re gisters Empty Mask
• NSSR: NSS Rising Interrupt Mask
0 = The corresponding interrupt is not enabled.
1 = The corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––TXEMPTYNSSR
76543210
TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF
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28.7.9 SPI Chip Select Register
Name: SPI_CSR0... SPI_CSR3
Access Type: Read-write
• CPOL: Clock Polarity
0 = The inactive state value of SPCK is logic level zero.
1 = The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the required
clock/data relationship between master and slave devices.
• NCPHA: Clock Phase
0 = Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
1 = Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
• CSAAT: Chip Select Active After Transfer
0 = The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
1 = The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is requested
on a different chip select.
• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
31 30 29 28 27 26 25 24
DLYBCT
23 22 21 20 19 18 17 16
DLYBS
15 14 13 12 11 10 9 8
SCBR
76543210
BITS CSAAT – NCPHA CPOL
BITS Bit s Per Transfer
0000 8
0001 9
0010 10
0011 11
0100 12
0101 13
0110 14
0111 15
1000 16
1001 Reserved
1010 Reserved
1011 Reserved
1100 Reserved
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• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the Master Clock MCK. The Baud
rate is selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
• DLYBCT: Delay Between Consecutive Transfer s
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the char-
acter transfers.
Otherwise, the following equation determines the delay:
1101 Reserved
1110 Reserved
1111 Reserved
BITS Bit s Per Transfer
SPCK Baudrate MCK
SCBR
---------------
=
Delay Before SPCK DLYBS
MCK
-------------------
=
Delay Between Consecutive Transfers 32 DLYBCT×MCK
------------------------------------
=
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29. Two-wire Interface (TWI)
29.1 Overview
The Two-wire Interface (TWI) interconnects components on a unique two-wire bus, made up of one clock line and one
data line with speeds of up to 400 Kbits per second, based on a byte-oriented transfer format. It can be used with any
Atmel Two-wire Interface bus Serial EEPROM and I²C compatible device such as Real Time Clock (RTC), Dot
Matrix/Graphic LCD Controllers and Temperature Sensor, to name but a few. The TWI is programmable as master
transmitter or master receiver with sequential or single-byte access. A configurable baud rate generator permits the
output data rate to be adapted to a wide range of core clock frequencies. Below, Table 29-1 lists the compatibility level of
the Atmel Two-wire Interface and a full I2C compatible device.
Notes: 1. START + b000000001 + Ack + Sr
2. A repeated start condition is only supported in Master Receiver mode. See Section 29.5.5 “Internal
Address” on page 274
29.2 Block Diagram
Figure 29-1. Block Diagram
Table 29-1 . Atmel TWI compatibility with i2C Standard
I2C Standard Atmel TWI
Standard Mode Speed (100 KHz) Supported
Fast Mode Spe ed (400 KHz) Supported
7 or 10 bits Slave Addressing Supported
START BYTE(1) Not Supported
Repeated Start (Sr) Condition Not Fully Supported(2)
ACK and NACK Management Supported
Slope control and input filtering (Fast mode) Not Supported
Clock strectching Supported
APB Bridge
PMC MCK
Two-wire
Interface
PIO
AIC
TWI
Interrupt
TWCK
TWD
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29.3 Application Block Diagram
Figure 29-2. Application Block Diagram
29.3.1 I/O Lines Description
29.4 Product Dependencies
29.4.1 I/O Lines
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current source or pull-up
resistor (see Figure 29-2 on page 270). When the bus is free, both lines are high. The output stages of devices
connected to the bus must have an open-drain or open-collector to perform the wired-AND function.
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer must perform the following
steps:
Program the PIO controller to:
Dedicate TWD and TWCK as peripheral lines.
Define TWD and TWCK as open-drain.
29.4.2 Power Management
Enable the peripheral clock.
The TWI interface may be clocked through the Power Management Controller (PMC), thus the programmer must first
configure the PMC to enable the TWI clock.
29.4.3 Interrupt
The TWI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). In order to handle
interrupts, the AIC must be programmed before configuring the TWI.
Host with
TWI
Interface
TWD
TWCK
Atmel TWI
Serial EEPROM I²C RTC I²C LCD
Controller
Slave 1 Slave 2 Slave 3
VDD
I²C Temp.
Sensor
Slave 4
Rp: Pull up value as given by the I²C Standard
Rp Rp
Table 29-2. I/O Lines Description
Pin Name Pin Description Typ e
TWD Two-wire Serial Data Input/Output
TWCK Two-wire Serial Clock Input/Output
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29.5 Functional Description
29.5.1 Transfer format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must be followed by an
acknowledgement. The number of bytes per transfer is unlimited (see Figure 29-4 on page 271).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure 29-3 on page 271).
A high-to-low transition on the TWD line while TWCK is high defines the START condition.
A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 29-3. START and STOP Conditions
Figure 29-4. Transfer Format
29.5.2 Modes of Operation
The TWI has two modes of operation:
Master transmitter mode
Master receiver mode
The TWI Control Register (TWI_CR) allows configuration of the interface in Master Mode. In this mode, it generates the
clock according to the value programmed in the Clock Waveform Generator Register (TWI_CWGR). This register de fines
the TWCK signal completely, enabling the interface to be adapted to a wide range of clocks.
29.5.3 Master Transmitter Mode
After the master initiates a Start condition when writing into the Transmit Holding Register, TWI_THR, it sends a 7-bit
slave address, configured in the Master Mode register (DADR in TWI_MMR), to notify the slave device. The bit following
the slave address indicates the transfer direction, 0 in this case (MREAD = 0 in TWI_MMR).
The TWI transfers require the slave to acknowledge each received byte. During the acknowledge clock pulse (9th pulse),
the master releases the data line (HIGH), enabling the slave to pull it down in order to generate the acknowledge. The
master polls the data line during this clock pulse and sets the Not Acknowledge bit (NACK) in the status register if the
slave does not acknowledge the byte. As with the other status bits, an interrupt can be generated if enabled in the
interrupt enable register (TWI_IER). If the slave acknowledges the byte, the data written in the TWI_THR, is then shifted
in the internal shifter and transferred. When an acknowledge is detected, the TXRDY bit is set until a new write in the
TWI_THR. When no more data is written into the TWI_THR, the master generates a stop condition to end the transfer.
The end of the complete transfer is marked by the TWI_TXCOMP bit set to one. See Figure 29-5, Figure 29-6, and
Figure 29-7.
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack Data Ack Data Ack Stop
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Figure 29-5. Master Write with One Data Byte
Figure 29-6. Master Write with Multiple Data Byte
Figure 29-7. Master Write with One Byte Internal Address and Multiple Data Bytes
TXCOMP
TXRDY
Write THR (D ATA) STOP sent automaticaly
(ACK received and TXRDY = 1)
TWD A DATA AS DADR W P
A DATA n AS DADR W DATA n+5 A PDATA n+x A
TXCOMP
TXRDY
Write THR (Data n) Write THR (Data n+1) Write THR (Data n+x)
Last data sent STOP sent automaticaly
(ACK received and TXRDY = 1)
TWD
A IADR(7:0) A DATA n AS DADR W DATA n+5 A PDATA n+x A
TXCOMP
TXRDY
TWD
Write THR (Data n) Write THR (Data n+1) Write THR (Data n+x)
Last data sent STOP sent automaticaly
(ACK received and TXRDY = 1)
273
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29.5.4 Master Receiver Mode
The read sequence begins by setting the START bit. After the start condition has been sent, the master sends a 7-bit
slave address to notify the slave device. The bit following the slave address indicates the transfer direction, 1 in this case
(MREAD = 1 in TWI_MMR). During the acknowledge clock pulse (9th pulse), the master releases the data line (HIGH),
enabling the slave to pull it down in order to generate the acknowledge. The master polls the data line during this clock
pulse and sets the NACK bit in the status register if the slave does not acknowledge the byte.
If an acknowledge is received, the master is then ready to receive data from the slave. After data has been received, the
master sends an acknowledge condition to notify the slave that the data has been received except for the last data, after
the stop condition. See Figure 29-9. When the RXRDY bit is set in the status register, a character has been received in
the receive-holding register (TWI_RHR). The RXRDY bit is reset when reading the TWI_RHR.
When a single data byte read is performed, with or without internal address (IADR), the START and STOP bits must be
set at the same time. See Figure 29-8. When a multiple data byte read is performed, with or without internal address
(IADR), the STOP bit must be set after the next-to-last data received. See Figure 29-9. For Internal Address usage see
Section 29.5.5.
Figure 29-8. Master Read with One Data Byte
Figure 29-9. Master Read with Multiple Data Bytes
AS DADR R DATA N P
TXCOMP
Write START &
STOP Bit
RXRDY
Read RHR
TWD
N
AS DADR R DATA n A ADATA (n+1) A DATA (n+m)DATA (n+m)-1 PTWD
TXCOMP
Write START Bit
RXRDY
Write STOP Bit
after next-to-last data read
Read RHR
DATA n Read RHR
DATA (n+1) Read RHR
DATA (n+m)-1 Read RHR
DATA (n+m)
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29.5.5 Internal Address
The TWI interface can perform various transfer formats: Transfers with 7-bit slave address devices and 10-bit slave
address devices.
29.5.5.1 7-bit Slave Addressing
When Addressing 7-bit slave devices, the internal address bytes are used to perform random address (read or write)
accesses to reach one or more data bytes, within a memory page location in a serial memory, for example. When
performing read operations with an internal address, the TWI performs a write operation to set the internal address into
the slave device, and then switch to Master Receiver mode. Note that the second start condition (after sending the IADR)
is sometimes called “repeated start” (Sr) in I2C fully-compatible devices. See Figure 29-10, Figure 29-11 and Figure 29-
12.
The three internal address bytes are configurable through the Master Mode register (TWI_MMR).
If the slave device supports only a 7-bit address, i.e. no internal address, IADRSZ must be set to 0.
In the figures below the following abbreviations are used:
Figure 29-10. Master Write with One, Two or T hre e Bytes Internal Address and One Data Byte
Figure 29-11. Master Read with One, Two or Three Bytes Internal Addres s and One Data Byte
29.5.5.2 10-bit Slave Addressing
For a slave address higher than 7 bits, the user must configure the address size (IADRSZ) and set the other slave
address bits in the internal address register (TWI_IADR). The two remaining Internal address bytes, IADR[15:8] and
IADR[23:16] can be used the same as in 7-bit Slave Addressing.
Example: Address a 10-bit device (10-bit device address is b1 b2 b3 b4 b5 b6 b7 b8 b9 b10)
SStart
PStop
WWrite
RRead
AAcknowledge
NNot Acknowledge
DADR Device Address
IADR Internal Address
S DADR W A IADR(23:16) A IADR(15:8) A IADR(7:0) A DATA A P
S DADR W A IADR(15:8) A IADR(7:0) A PDATA A
A IADR(7:0) A P
DATA AS DADR W
TWD
Three bytes internal address
Two bytes internal address
One byte internal address
TWD
TWD
SA
S DADR W A IADR(23:16) A IADR(15:8) A IADR(7:0) A
S DADR W A IADR(15:8) A IADR(7:0) A
A IADR(7:0) AS DADR W
DATA N P
S DADR R A
S DADR R A DATA N P
DADR
R DATA N P
TWD
TWD
TWD
Three bytes internal address
Two bytes internal address
One byte internal address
275
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1. Program IADRSZ = 1,
2. Program DADR with 1 1 1 1 0 b1 b2 (b1 is the MSB of the 10-bit address, b2, etc.)
3. Program TWI_IADR with b3 b4 b5 b6 b7 b8 b9 b10 (b10 is the LSB of the 10-bit address)
Figure 29-12 below shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates the use of internal
addresses to access the device.
Figure 29-12. Internal Address Usage
S
T
A
R
T
M
S
B
Device
Address
0
L
S
B
R
/
W
A
C
K
M
S
B
W
R
I
T
E
A
C
K
A
C
K
L
S
B
A
C
K
FIRST
WORD ADDRESS SECOND
WORD ADDRESS DATA
S
T
O
P
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29.5.6 Read/Write Flowcharts
The following flowcharts shown in Figure 29-13, Figure 29-14 on page 277, Figure 29-15 on page 278, Figure 29-16 on
page 279, Figure 29-17 on page 280 and Figure 29-18 on page 281 give examples for read and write operations. A
polling or interrupt method can be used to check the status bits. The interrupt method requires that the interrupt enable
register (TWI_IER) be configured first.
Figure 29-13. TWI Write Operation with Single Data Byte without Internal Address
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address (DADR)
- Transfer direction bit
Write ==> bit MREAD = 0
Load Transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Read Status register
TXCOMP = 1?
Transfer finished
Yes
Yes
BEGIN
No
No
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Figure 29-14. TWI Write Operation with Single Data Byte and Internal Address
BEGIN
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address (DADR)
- Internal address size (IADRSZ)
- Transfer direction bit
Write ==> bit MREAD = 0
Load transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Read Status register
TXCOMP = 1?
Transfer finished
Set the internal address
TWI_IADR = address
Yes
Yes
No
No
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Figure 29-15. TWI Write Operation with Multiple Data Bytes with or without Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address
- Internal address size (if IADR used)
- Transfer direction bit
Write ==> bit MREAD = 0
Internal address size = 0?
Load Transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Data to send?
Read Status register
TXCOMP = 1?
END
BEGIN
Set the internal address
TWI_IADR = address
Yes
TWI_THR = data to send
Yes
Yes
Yes
No
No
No
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
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Figure 29-16. TWI Read Operation with Single Data Byte without Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address
- Transfer direction bit
Read ==> bit MREAD = 1
Start the transfer
TWI_CR = START | STOP
Read status register
RXRDY = 1?
Read Status register
TXCOMP = 1?
END
BEGIN
Yes
Yes
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Read Receive Holding Register
No
No
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Figure 29-17. TWI Read Operation with Single Data Byte and Internal Address
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address
- Internal address size (IADRSZ)
- Transfer direction bit
Read ==> bit MREAD = 1
Read Status register
TXCOMP = 1?
END
BEGIN
Yes
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Yes
Set the internal address
TWI_IADR = address
Start the transfer
TWI_CR = START | STOP
Read Status register
RXRDY = 1?
Read Receive Holding register
No
No
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Figure 29-18. TWI Read Operation with Multiple Data Bytes with or without Internal Address
Internal address size = 0?
Start the transfer
TWI_CR = START
Stop the transfer
TWI_CR = STOP
Read Status register
RXRDY = 1?
Last data to read
but one?
Read status register
TXCOMP = 1?
END
Set the internal address
TWI_IADR = address
Yes
Yes
Yes
No
Yes
Read Receive Holding register (TWI_RHR)
No
Set the Control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address
- Internal address size (if IADR used)
- Transfer direction bit
Read ==> bit MREAD = 1
BEGIN
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
No
Read Status register
RXRDY = 1?
Yes
Read Receive Holding register (TWI_RHR)
No
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29.6 TWI User Interface
Table 29-3. Regist er Mapping
Offset Register Name Access Reset
0x0000 Control Register TWI_CR Write-only N/A
0x0004 Master Mode Register TWI_MMR Read-write 0x0000
0x0008 Reserved - - -
0x000C Internal Address Register TWI_IADR Read-write 0x0000
0x0010 Clock Wa veform Generator Register TWI_CWGR Read-write 0x0000
0x0020 Status Register TWI_SR Read-only 0x0008
0x0024 Interrupt Enable Register TWI_IER Write-only N/A
0x0028 Interrupt Disable Register TWI_IDR Write-only N/A
0x002C Interrupt Mask Register TWI_IMR Read-only 0x0000
0x0030 Receive Holding Register TWI_RHR Read-only 0x0000
0x0034 Tr ansmit Holding Register TWI_THR Read-wri te 0x0000
0x0038 - 0x00FC Reserved – – –
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29.6.1 TWI Control Register
Register Name: TWI_CR
Access Type: Write-only
• START: Send a START Condition
0 = No effect.
1 = A frame beginning with a START bit is transmitted according to the features defined in the mode register.
This action is necessary when the TWI peripheral wants to read data from a slave. When configured in Master Mode with a write
operation, a frame is sent as soon as the user writes a character in the Transmit Holding Register (TWI_THR).
• STOP: Send a STOP Condition
0 = No effect.
1 = STOP Condition is sent just after completing the current byte transmission in master read mode.
– In single data byte mast er read, the START and STOP must both be set.
– In multiple data bytes master read, the STOP must be set after the last data received but one.
– In master read mode, if a NACK bit is received, the STOP is automatically performed.
– In multiple data write operat ion, when both THR and shift registe r are empty, a ST OP condition is au tomatically
sent.
• MSEN: TWI Master Transfer Enabled
0 = No effect.
1 = If MSDIS = 0, the master data transfer is enabled.
• MSDIS: TWI Master Transfer Disabled
0 = No effect.
1 = The master data transfer is disabled, all pending data is transmitted. The shifter and holding characters (if they contain data)
are transmitted in case of write operation. In read operation, the character being transferred must be completely received before
disabling.
• SWRST: Software Reset
0 = No effect.
1 = Equivalent to a system reset.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SWRST – – – MSDIS MSEN STOP START
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29.6.2 TWI Master Mode Register
Register Name:TWI_MMR
Address Type: Read-write
• IADRSZ: Internal Device Address Size
• MREAD: Master Read Direction
0 = Master write direction.
1 = Master read direction.
• DADR: Device Address
The device address is used to access slave devices in read or write mode.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–DADR
15 14 13 12 11 10 9 8
–––MREAD–– IADRSZ
76543210
––––––––
Table 29-4.
IADRSZ[9:8]
0 0 No internal device address (Byte command protocol)
0 1 One-byte internal device address
1 0 Two-byte internal device address
1 1 Three-byte internal device address
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29.6.3 TWI Internal Address Register
Register Name:TWI_IADR
Access Type: Read-write
• IADR: Internal Address
0, 1, 2 or 3 bytes depending on IADRSZ.
– Low significant byte address in 10-bit mode addresses.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
IADR
15 14 13 12 11 10 9 8
IADR
76543210
IADR
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29.6.4 TWI Clock Waveform Generator Register
Register Name:TWI_CWGR
Access Type: Read-write
• CLDIV: Clock Low Divider
The SCL low period is defined as follows:
• CHDIV: Clock High Divider
The SCL high period is defined as follows:
• CKDIV: Clock Divider
The CKDIV is used to increase both SCL high and low periods.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––– CKDIV
15 14 13 12 11 10 9 8
CHDIV
76543210
CLDIV
Tlow CLDIV(2CKDIV
×()3)+TMCK
×=
Thigh CHDIV(2CKDIV
×()3)+TMCK
×=
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29.6.5 TWI Status Register
Register Name:TWI_SR
Access Type: Read-only
• TXCOMP: Transmission Completed
0 = During the length of the current frame.
1 = When both holding and shift registers are empty and STOP condition has been sent, or when MSEN is set (enable TWI).
• RXRDY: Receive Ho ld ing Register Ready
0 = No character has been received since the last TWI_RHR read operation.
1 = A byte has been received in the TWI_RHR since the last read.
• TXRDY: Transmit Holding Register Ready
0 = The transmit holding register has not been transferred into shift register. Set to 0 when writing into TWI_THR register.
1 = As soon as data byte is transferred from TWI_THR to internal shifter or if a NACK error is detected, TXRDY is set at the same
time as TXCOMP and NACK. TXRDY is also set when MSEN is set (enable TWI).
• OVRE: Overrun Error (clear on read)
This bit is only used in Master mode.
0 = TWI_RHR has not been loaded while RXRDY was set
1 = TWI_RHR has been loaded while RXRDY was set. Reset by read in TWI_SR when TXCOMP is set.
• NACK: Not Acknowledged
0 = Each data byte has been correctly received by the far-end side TWI slave component.
1 = A data byte has not been acknowledged by the slave component. Set at the same time as TXCOMP. Reset after read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––NACK
76543210
– OVRE – – – TXRDY RXRDY TXCOMP
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29.6.6 TWI Interrupt Enable Register
Register Name:TWI_IER
Access Type: Write-only
• TXCOMP: Transmission Completed
• RXRDY: Receive Ho ld ing Register Ready
• TXRDY: Transmit Holding Register Ready
OVRE: Overrun Error Interrupt Enable
• NACK: Not Acknowledge
0 = No effect.
1 = Enables the corresponding interrupt.
29.6.7 TWI Interrupt Disable Register
Register Name:TWI_IDR
Access Type: Write-only
• TXCOMP: Transmission Completed
• RXRDY: Receive Ho ld ing Register Ready
• TXRDY: Transmit Holding Register Ready
• OVRE: Overrun Error Interrupt Disable
• NACK: Not Acknowledge
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––NACK
76543210
– OVRE – – – TXRDY RXRDY TXCOMP
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––NACK
76543210
– OVRE – – – TXRDY RXRDY TXCOMP
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29.6.8 TWI Interrupt Mask Register
Register Name:TWI_IMR
Access Type: Read-only
• TXCOMP: Transmission Completed
• RXRDY: Receive Ho ld ing Register Ready
• TXRDY: Transmit Holding Register Ready
• OVRE: Overrun Error Interrupt Mask
• NACK: Not Acknowledge
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
29.6.9 TWI Receive Holding Register
Register Name: TWI_RHR
Access Type: Read-only
• RXDATA: Receive Holding Da ta
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––NACK
76543210
–––––TXRDYRXRDYTXCOMP
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RXDATA
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29.6.10 TWI Transmit Holding Register
Register Name:TWI_THR
Access Type: Read-write
• TXDATA: Transmit Holding Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TXDATA
291
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30. Universal Synchronous Asynchronous Receiver Transceiver (USART)
30.1 Overview
The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full duplex universal
synchronous asynchronous serial link. Data frame format is widely programmable (data length, parity, number of stop
bits) to support a maximum of standards. The receiver implements parity error, framing error and overrun error detection.
The receiver time-out enables handling variable-length frames and the transmitter timeguard facilitates communications
with slow remote devices. Multidrop communications are also supported through address bit handling in reception and
transmission.
The USART features three test modes: remote loopback, local loopback and automatic echo.
The USART supports specific operating modes providing interfaces on RS485 buses, with ISO7816 T = 0 or T = 1 smart
card slots, infrared transceivers and connection to modem ports. The hardware handshaking feature enables an out-of-
band flow control by automatic management of the pins RTS and CTS.
The USART supports the connection to the Peripheral DMA Controller, which enables data transfers to the transmitter
and from the receiver. The PDC provides chained buffer management without any intervention of the processor.
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30.2 Block Diagram
Figure 30-1. USART Block Diagram
Peripheral DMA
Controller
Channel Channel
AIC
Receiver
USART
Interrupt
RXD
TXD
SCK
USART PIO
Controller
CTS
RTS
DTR
DSR
DCD
RI
Transmitter
Modem
Signals
Control
Baud Rate
Generator
User Interface
PMC MCK
SLCK
DIV MCK/DIV
APB
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30.3 Application Block Diagram
Figure 30-2. Application Block Diagram
30.4 I/O Lines Description
Smart
Card
Slot
USART
RS232
Drivers
Modem
RS485
Drivers
Differential
Bus
IrDA
Transceivers
Modem
Driver
Field Bus
Driver EMV
Driver IrDA
Driver
IrLAP
RS232
Drivers
Serial
Port
Serial
Driver
PPP
PSTN
Table 30-1. I/O Line Description
Name Description Type Activ e Level
SCK Serial Clock I/O
TXD Transmit Serial Data I/O
RXD Receive Serial Data Input
RI Ring Indicato r Input Low
DSR Data Set Ready Input Low
DCD Data Carrier Detect Input Low
DTR Data Terminal Ready Output Low
CTS Clear to Send Input Low
RTS Request to Send Output Low
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30.5 Product Dependencies
30.5.1 I/O Lines
The pins used for interfacing the USART may be multiplexed with the PIO lines. The programmer must first program the
PIO controller to assign the desired USART pins to their peripheral function. If I/O lines of the USART are not used by the
application, they can be used for other purposes by the PIO Controller.
To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up is mandatory. If the
hardware handshaking feature or Modem mode is used, the internal pull up on TXD must also be enabled.
All the pins of the modems may or may not be implemented on the USART. Only USART1 is fully equipped with all the
modem signals. On USARTs not equipped with the corresponding pin, the associated control bits and statuses have no
effect on the behavior of the USART.
30.5.2 Power Management
The USART is not continuously clocked. The programmer must first enable the USART Clock in the Power Management
Controller (PMC) before using the USART. However, if the application does not require USART operations, the USART
clock can be stopped when not needed and be restarted later. In this case, the USART will resume its operations where
it left off.
Configuring the USART does not require the USART clock to be enabled.
30.5.3 Interrupt
The USART interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the
USART interrupt requires the AIC to be programmed first. Note that it is not recommended to use the USART interrupt
line in edge sensitive mode.
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30.6 Functional Description
The USART is capable of managing several types of serial synchronous or asynchronous communications.
It supports the following communication modes:
5- to 9-bit full-duplex asynchronous serial communication
MSB- or LSB-first
1, 1.5 or 2 stop bits
Parity even, odd, marked, space or none
By 8 or by 16 over-sampling receiver frequency
Optional hardware handshaking
Optional modem signals management
Optional break management
Optional multidrop serial communication
High-speed 5- to 9-bit full-duplex synchronous serial communication
MSB- or LSB-first
1 or 2 stop bits
Parity even, odd, marked, space or none
By 8 or by 16 over-sampling frequency
Optional hardware handshaking
Optional modem signals management
Optional break management
Optional multidrop serial communication
RS485 with driver control signal
ISO7816, T0 or T1 protocols for interfacing with smart cards
NACK handling, error counter with repetition and iteration limit
InfraRed IrDA Modulation and Demodulation
Test modes
Remote loopback, local loopback, automatic echo
30.6.1 Baud Rate Generator
The Baud Rate Generator provides the bit period clock named the Baud Rate Clock to both the receiver and the
transmitter.
The Baud Rate Generator clock source can be selected by setting the USCLKS field in the Mode Register (US_MR)
between:
the Master Clock MCK
a division of the Master Clock, the divider being product dependent, but generally set to 8
the external clock, available on the SCK pin
The Baud Rate Generator is based upon a 16-bit divider, which is programmed with the CD field of the Baud Rate
Generator Register (US_BRGR). If CD is programmed at 0, the Baud Rate Genera tor does not generate any clock. If CD
is programmed at 1, the divider is bypassed and becomes inactive.
If the external SCK clock is selected, the duration of the low and high levels of the signal provided on the SCK pin must
be longer than a Master Clock (MCK) period. The frequency of the signal provided on SCK must be at least 4.5 times
lower than MCK.
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Figure 30-3. Baud Rate Generator
30.6.1.1 Baud Rate in Asynchronous Mode
If the USART is programmed to operate in asynchronous mode, the selected clock is first divided by CD, which is field
programmed in the Baud Rate Generator Register (US_BRGR). The resulting clock is provided to the receiver as a
sampling clock and then divided by 16 or 8, depending on the programming of the OVER bit in US_MR.
If OVER is set to 1, the receiver sampling is 8 times higher than the baud rate clock. If OVER is cleared, the sampling is
performed at 16 times the baud rate clock.
The following formula performs the calculation of the Baud Rate.
This gives a maximum baud rate of MCK divided by 8, assuming that MCK is the highest possible clock and that OVER
is programmed at 1.
30.6.1.2 Baud Rate Calculation Example
Table 30-2 shows calculations of CD to obtain a baud rate at 38400 bauds for different source clock frequencies. This
table also shows the actual resulting baud rate and the error.
MCK/DIV 16-bit Counter
0
Baud Rate
Clock
CD
CD
Sampling
Divider
0
1
>1
Sampling
Clock
Reserved
MCK
SCK
USCLKS
OVER
SCK
SYNC
SYNC
USCLKS = 3
1
0
2
30
1
0
1
FIDI
Baudrate SelectedClock
82 Over–()CD()
--------------------------------------------
=
Table 30-2. Baud Rate Example (OVER = 0)
Source Clock Expected Baud
Rate Calculation Result CD Actual Baud Rate Error
MHz Bit/s Bit/s
3 686 400 38 400 6.00 6 38 400 .00 0.00%
4 915 200 38 400 8.00 8 38 400 .00 0.00%
5 000 000 38 400 8.14 8 39 062 .50 1.70%
7 372 800 38 400 12.00 12 38 400.00 0.00%
8 000 000 38 400 13.02 13 38 461.54 0.16%
12 000 000 38 400 19.53 20 37 500.00 2 .40%
12 288 000 38 400 20.00 20 38 400.00 0 .00%
14 318 180 38 400 23.30 23 38 908.10 1 .31%
14 745 600 38 400 24.00 24 38 400.00 0 .00%
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The baud rate is calculated with the following formula:
The baud rate error is calculated with the following formula. It is not recommended to work with an error higher than 5%.
30.6.1.3 Fractional Baud Rate in Asynchronous Mode
The Baud Rate generator previously defined is subject to the following limitation: the output frequency changes by only
integer multiples of the reference frequency. An approach to this problem is to integrate a fractional N clock generator
that has a high resolution. The generator architecture is modified to obtain Baud Rate changes by a fraction of the
reference source clock. This fractional part is programmed with the FP field in the Baud Rate Generator Register
(US_BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the clock divider. This feature is
only available when using USART normal mode. The fractional Baud Rate is calculated using the following formula:
The modified architecture is presented below:
18 432 000 38 400 30.00 30 38 400.00 0 .00%
24 000 000 38 400 39.06 39 38 461.54 0 .16%
24 576 000 38 400 40.00 40 38 400.00 0 .00%
25 000 000 38 400 40.69 40 38 109.76 0 .76%
32 000 000 38 400 52.08 52 38 461.54 0 .16%
32 768 000 38 400 53.33 53 38 641.51 0 .63%
33 000 000 38 400 53.71 54 38 194.44 0 .54%
40 000 000 38 400 65.10 65 38 461.54 0 .16%
50 000 000 38 400 81.38 81 38 580.25 0 .47%
Table 30-2. Baud Rate Example (OVER = 0) (Continued)
Source Clock Expected Baud
Rate Calculation Result CD Actual Baud Rate Error
BaudRate MCK CD 16×⁄=
Error 1ExpectedBaudRate
ActualBaudRate
---------------------------------------------------
–=
Baudrate SelectedClock
82 Over–()CD FP
8
-------
+
----------------------------------------------------------------
=
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Figure 30-4. Fractio na l Baud Rate Generator
30.6.1.4 Baud Rate in Synchronous Mode
If the USART is programmed to operate in synchronous mode, the selected clock is simply divided by the field CD in
US_BRGR.
In synchronous mode, if the external clock is selected (USCLKS = 3), the clock is provided directly by the signal on the
USART SCK pin. No division is active. The value written in US_BRGR has no effect. The external clock frequency must
be at least 4.5 times lower than the system clock.
When either the external clock SCK or the internal clock divided (MCK/DIV) is selected, the value programmed in CD
must be even if the user has to ensure a 50:50 mark/space ratio on the SCK pin. If the internal clock MCK is selected, the
Baud Rate Generator ensures a 50:50 duty cycle on the SCK pin, even if the value programmed in CD is odd.
30.6.1.5 Baud Rate in ISO 7816 Mode
The ISO7816 specification defines the bit rate with the following formula:
where:
B is the bit rate
Di is the bit-rate adjustment factor
Fi is the clock frequency division factor
f is the ISO7816 clock frequency (Hz)
Di is a binary value encoded on a 4-bit field, named DI, as represented in Table 30-3.
MCK/DIV 16-bit Counter
0
Baud Rate
Clock
CD
CD
Sampling
Divider
0
1
>1
Sampling
Clock
Reserved
MCK
SCK
USCLKS
OVER
SCK
SYNC
SYNC
USCLKS = 3
1
0
2
30
1
0
1
FIDI
glitch-free
logic
Modulus
Control
FP
FP
BaudRate SelectedClock
CD
--------------------------------------
=
BDi
Fi
------f×=
Table 30-3. Binary and Decimal Values for Di
DI field 0001 0010 0011 0100 0101 0110 1000 1001
Di (decimal)1 2 4 8 163212 20
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Fi is a binary value encoded on a 4-bit field, named FI, as represented in Table 30-4.
Table 30-5 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the baud rate clock.
If the USART is configured in ISO7816 Mode, the clock selected by the USCLKS field in the Mode Register (US_MR) is
first divided by the value programmed in the field CD in the Baud Rate Generator Register (US_BRGR). The resulting
clock can be provided to the SCK pin to feed the smart card clock inputs. This means that the CLKO bit can be set in
US_MR.
This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio register (US_FIDI). This
is performed by the Sampling Divider, which performs a division by up to 2047 in ISO7816 Mode. The non-integer values
of the Fi/Di Ratio are not supported and the user must program the FI_DI_RATIO field to a value as close as possible to
the expected value.
The FI_DI_RATIO field resets to the value 0x174 (372 in decimal) and is the most common divider between the ISO7816
clock and the bit rate (Fi = 372, Di = 1).
Figure 30-5 shows the relation between the Elementary Time Unit, corresponding to a bit time, and the ISO 7816 clock.
Figure 30-5. Elementary Time Unit (ETU)
30.6.2 Receiver and Transmitter Control
After reset, the receiver is disabled. The user must enable the receiver by setting the RXEN bit in the Control Register
(US_CR). However, the receiver registers can be programmed before the receiver clock is enabled.
After reset, the transmitter is disabled. The user must enable it by setting the TXEN bit in the Control Register (US_CR).
However, the transmitter registers can be programmed before being enabled.
Table 30-4. Binary and Decimal Values for Fi
FI field 0000 0001 0010 0011 0100 0101 0110 1001 1010 1011 1100 1101
Fi (decimal 372 372 558 744 1116 1488 1860 512 768 1024 1536 2048
Table 30-5. Possible Values for the Fi/Di Ratio
Fi/Di 372 558 774 1116 1488 1806 512 768 1024 1536 2048
1 372 558 744 1116 1488 1860 512 768 1024 1536 2048
2 186 279 372 558 744 930 256 384 512 768 1024
4 93 139.5 186 279 372 465 128 192 256 384 512
8 46.5 69.75 93 139.5 186 232.5 64 96 128 192 256
16 23.25 34.87 46.5 69.75 93 116.2 32 48 64 96 128
32 11.62 17.43 23.25 34.87 46.5 58.13 16 24 32 48 64
12 31 46.5 62 93 124 155 42.66 64 85.33 128 170.6
20 18.6 27.9 37.2 55.8 74.4 93 25.6 38.4 51.2 76.8 102.4
1 ETU
ISO7816 Clock
on SCK
ISO7816 I/O Line
on TXD
FI_DI_RATIO
ISO7816 Clock Cycles
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The Receiver and the Transmitter can be enabled together or independently.
At any time, the software can perform a reset on the receiver or the transmitter of the USART by setting the
corresponding bit, RSTRX and RSTTX respectively, in the Control Register (US_CR). The software resets clear the
status flag and reset internal state machines but the user interface config uration registers hold the value configured prior
to software reset. Regardless of what the receiver or the transmitter is performing, the communication is immediately
stopped.
The user can also independently disable the receiver or the transmitter by setting RXDIS and TXDIS respectively in
US_CR. If the receiver is disabled during a character reception, the USART waits until the end of reception of the current
character, then the reception is stopped. If the transmitter is disabled while it is operating, the USART waits the end of
transmission of both the current character and character being stored in the Transmit Holding Register (US_THR). If a
timeguard is programmed, it is handled normally.
30.6.3 Synchronous and Asynchronous Modes
30.6.3.1 Transmitter Operations
The transmitter performs the same in both synchronous and asynchronous operating modes (SYNC = 0 or SYNC = 1).
One start bit, up to 9 data bits, one optional parity bit and up to two stop bits are successively shifted out on the TXD pin
at each falling edge of the programmed serial clock.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register (US_MR). Nine bits are
selected by setting the MODE 9 bit regardless of the CHRL field. The parity bit is set according to the PAR field in
US_MR. The even, odd, space, marked or none parity bit can be configured. The MSBF field in US_MR configures which
data bit is sent first. If written at 1, the most significant bit is sent first. At 0, the less significant bit is sent first. The number
of stop bits is selected by the NBSTOP field in US_MR. The 1.5 stop bit is supported in asynchronous mode only.
Figure 30-6 . Character Transmit
The characters are sent by writing in the Transmit Holding Register (US_THR). The transmitter reports two status bits in
the Channel Status Register (US_CSR): TXRDY (Transmitter Ready), which indicates that US_THR is empty and
TXEMPTY, which indicates that all the characters written in US_THR have been processed. When the current character
processing is completed, the last character written in US_THR is transferred into the Shift Register of t he transmitter and
US_THR becomes empty, thus TXRDY raises.
Both TXRDY and TXEMPTY bits are low since the transmitter is disabled. Writing a character in US_THR while TXRDY
is active has no effect and the written character is lost.
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Example: 8-bit, Parity Enabled One Stop
Baud Rate
Clock
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Figure 30-7 . Tran sm itter Status
30.6.3.2 Asynchronous Receiver
If the USART is programmed in asynchronous operating mode (SYNC = 0), the receiver oversamples the RXD input line.
The oversampling is either 16 or 8 times the Baud Rate clock, depending on the OVER bit in the Mode Register
(US_MR).
The receiver samples the RXD line. If the line is sampled during one half of a bit time at 0, a start bit is detected and data,
parity and stop bits are successively sampled on the bit rate clock.
If the oversampling is 16, (OVER at 0), a start is detected at the eighth sample at 0. Then, data bits, parity bit and stop bit
are sampled on each 16 sampling clock cycle. If the oversampling is 8 (OVER at 1), a start bit is detected at the fourth
sample at 0. Then, data bits, parity bit and stop bit are sampled on each 8 sampling clock cycle.
The number of data bits, first bit sent and parity mode are selected by the same fields and bits as the transmitter, i.e.
respectively CHRL, MODE9, MSBF and PAR. For the synchronization mechanism only, the number of stop bits has no
effect on the receiver as it considers only one stop bit, regardless of the field NBSTOP, so that resynchronization
between the receiver and the transmitter can occur. Moreover, as soon as the stop bit is sampled, the receiver starts
looking for a new start bit so that resynchronization can also be accomplished when the transmitter is operating with one
stop bit.
Figure 30-8 and Figure 30-9 illustrate start detection and character reception when USART operates in asynchronous
mode.
Figure 30-8. Asynchron ou s Sta rt Detection
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Start
Bit
Write
US_THR
D0 D1 D2 D3 D4 D5 D6 D7 Parity
Bit Stop
Bit
TXRDY
TXEMPTY
Sampling
Clock (x16)
RXD
Start
Detection
Sampling
Baud Rate
Clock
RXD
Start
Rejection
Sampling
12345678
123456701234
123456789 10111213141516D0
Sampling
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SAM7X Series [DATASHEET]
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Figure 30-9. Asynchronou s Cha r ac te r Recepti on
30.6.3.3 Synchronous Receiver
In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of the Baud Rate Clock. If a
low level is detected, it is considered as a start. All data bits, the parity bit and the stop bits are sampled and the receiver
waits for the next start bit. Synchronous mode operations provide a high speed transfer capability.
Configuration fields and bits are the same as in asynchronous mode.
Figure 30-10 illustrates a character reception in synchronous mode.
Figure 30-10. Synchronous Mode Character Reception
30.6.3.4 Receiver Operations
When a character reception is completed, it is transferred to the Receive Holding Register (US_RHR) and the RXRDY bit
in the Status Register (US_CSR) rises. If a character is completed while the RXRDY is set, the OVRE (Overrun Error) bit
is set. The last character is transferred into US_RHR and overwrites the previous one. The OVRE bit is cleared by writing
the Control Register (US_CR) with the RSTSTA (Reset Status) bit at 1.
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Parity
Bit Stop
Bit
Example: 8-bit, Parity Enabled
Baud Rate
Clock
Start
Detection 16
samples 16
samples 16
samples 16
samples 16
samples 16
samples 16
samples 16
samples 16
samples 16
samples
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Start
Sampling
Parity Bit Stop Bit
Example: 8-bit, Parity Enabled 1 Stop
Baud Rate
Clock
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Figure 30-11. Receiver Status
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
RXRDY
OVRE
D0 D1 D2 D3 D4 D5 D6 D7
Start
Bit Parity
Bit Stop
Bit
RSTSTA = 1
Read
US_RHR
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SAM7X Series [DATASHEET]
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30.6.3.5 Parity
The USART supports five parity modes selected by programming the PAR field in the Mode Register (US_MR). The PAR
field also enables the Multidrop mode, see “Multidrop Mode” on page 305. Even and odd parity bit generation and error
detection are supported.
If even parity is selected, the parity generator of the transmitter drives the parity bit at 0 if a number of 1s in the character
data bit is even, and at 1 if the number of 1s is odd. Accordingly, the receiver parity checker counts the number of
received 1s and reports a parity error if the sampled parity bit does not correspond. If odd parity is selected, the parity
generator of the transmitter drives the parity bit at 1 if a number of 1s in the character data bit is even, and at 0 if the
number of 1s is odd. Accordingly, the receiver parity checker counts the n umber of received 1s and reports a parity error
if the sampled parity bit does not correspond. If the mark parity is used, the parity generator of the transmitter drives the
parity bit at 1 for all characters. The receiver parity checker reports an error if the parity bit is sampled at 0. If the space
parity is used, the parity generator of the transmitter drives the parity bit at 0 for all characters. The receiver parity
checker reports an error if the parity bit is sampled at 1. If parity is disabled, the transmitter does not generate any parity
bit and the receiver does not report any parity error.
Table 30-6 shows an example of the parity bit for the character 0x41 (character ASCII “A”) depending on the
configuration of the USART. Because there are two bits at 1, 1 bit is added when a parity is odd, or 0 is added when a
parity is even.
When the receiver detects a parity error, it sets the PARE (Parity Error) bit in the Channel Status Register (US_CSR).
The PARE bit can be cleared by writing the Control Register (US_CR) with the RSTSTA bit at 1. Figure 30-12 illustrates
the parity bit status setting and clearing.
Figure 30-12. Parity Error
Table 30-6. Parity Bit Examples
Character Hexa Binary Parity Bit Parity Mode
A 0x41 0100 0001 1 Odd
A 0x41 0100 0001 0 Even
A 0x41 0100 0001 1 Mark
A 0x41 0100 0001 0 Space
A 0x41 0100 0001 None None
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Start
Bit Bad
Parity
Bit
Stop
Bit
Baud Rate
Clock
Write
US_CR
PARE
RXRDY
RSTSTA = 1
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30.6.3.6 Multidrop Mode
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the USART runs in Multidrop
Mode. This mode differentiates the data characters and the address characters. Data is transmitted with the parity bit at
0 and addresses are transmitted with the parity bit at 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when the parity bit is high and
the transmitter is able to send a character with the parity bit high when the Control Register is written with the SENDA bit
at 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit RSTSTA at 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this case, the next byte
written to US_THR is transmitted as an address. Any character written in US_THR without having written the command
SENDA is transmitted normally with the parity at 0.
30.6.3.7 Transmitter Timeguard
The timeguard feature enables the USART interface with slow remote devices.
The timeguard function enables the transmitter to insert an idle state on the TXD line between two characters. This idle
state actually acts as a long stop bit.
The duration of the idle state is programmed in the TG field of the Transmitter Timeguard Register (US_TTGR). When
this field is programmed at zero no timeguard is generated. Otherwise, the transmitter holds a high level on TXD after
each transmitted byte during the number of bit periods programmed in TG in addition to the number of stop bits.
As illustrated in Figure 30-13, the behavior of TXRDY and TXEMPTY status bits is modified by the programming of a
timeguard. TXRDY rises only when the start bit of the next character is sent, and thus remains at 0 during the timeguard
transmission if a character has been written in US_THR. TXEMPTY remains low until the timeguard transmission is
completed as the timeguard is part of the current character being transmitted.
Figure 30-13. Timeguard Operations
Table 30-7 indicates the maximum length of a timeguard period that the transmitter can handle in relation to the functio n
of the Baud Rate.
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Start
Bit
TG = 4
Write
US_THR
D0 D1 D2 D3 D4 D5 D6 D7 Parity
Bit Stop
Bit
TXRDY
TXEMPTY
TG = 4
Table 30-7. Maximum Timeguard Length Depending on Baud Rate
Baud Rate Bit time Timeguard
Bit/sec µs ms
1 200 833 212.50
9 600 104 26.56
14400 69.4 17.71
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30.6.3.8 Receiver Time-out
The Receiver Time-out provides support in handling variable-length frames. This feature detects an idle condition on the
RXD line. When a time-out is detected, the bit TIMEOUT in the Channel Status Register (US_CSR) rises and can
generate an interrupt, thus indicating to the driver an end of frame.
The time-out delay period (during which the receiver waits for a new character) is programmed in the TO field of the
Receiver Time-out Register (US_RTOR). If the TO field is programmed at 0, the Receiver Time-out is disabled and no
time-out is detected. The TIMEOUT bit in US_CSR remains at 0. Otherwise, the receiver loads a 16-bit counter with the
value programmed in TO. This counter is decremented at each bit period and reloaded each time a new character is
received. If the counter reaches 0, the TIMEOUT bit in the Status Register rises. Then, the user can either:
S top the counter clock until a new character is received. This is performed by writing the Control Register (US_CR)
with the STTTO (Start T ime-out) bit at 1. In this case, the idle st ate on RXD before a new character is received will
not provide a time-out. This prevents having to handle an interrupt before a character is received and allows
waiting for the next idle state on RXD after a frame is received.
Obtain an interrupt while no character is received. This is performed by writing US_CR with the RETTO (Reload
and Start Time-out) bit at 1. If RETTO is performed, the counter starts counting down immediately from the value
TO. This enables generation of a periodic interrupt so that a user time-out can be handled, for example when no
key is pressed on a keyboard.
If STTTO is performed, the counter clock is stopped until a first character is received. The idle state on RXD before the
start of the frame does not provide a time-out. This prevents having to obtain a periodic interrupt and enables a wait of
the end of frame when the idle state on RXD is detected.
If RETTO is performed, the counter starts counting down immediately from the value TO. This enables generation of a
periodic interrupt so that a user time-out can be handled, for example when no key is pressed on a keyboard.
Figure 30-14 shows the block diagram of the Receiver Time-out feature.
Figure 30-14. Receiver Time-out Block Diagram
19200 52.1 13.28
28800 34.7 8.85
33400 29.9 7.63
56000 17.9 4.55
57600 17.4 4.43
115200 8.7 2.21
Table 30-7. Maximum Timeguard Length Depending on Baud Rate (Continued)
Baud Rate Bit time Timeguard
16-bit Time-out
Counter
0
TO
TIMEOUT
Baud Rate
Clock
=
Character
Received
RETTO
Load
Clock
16-bit
Value
STTTO
DQ
1
Clear
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Table 30-8 gives the maximum time-out period for some standard baud rates.
30.6.3.9 Framing Error
The receiver is capable of detecting framing errors. A framing error happens when the stop bit of a received character is
detected at level 0. This can occur if the receiver and the transmitter are fully desynchronized.
A framing error is reported on the FRAME bit of the Channel Status Register (US_CSR). The FRAME bit is asserted in
the middle of the stop bit as soon as the framing error is detected. It is cleared by writing the Control Register (US_CR)
with the RSTSTA bit at 1.
Figure 30-15. Framing Error Status
30.6.3.10 Transmit Break
The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the TXD line
low during at least one complete character. It appears the same as a 0x00 character sent with the parity and the stop bits
at 0. However, the transmitter holds the TXD line at least during one character until the user requests the break condition
to be removed.
Table 30-8. Maximum Time-out Period
Baud Rate Bit Time Time-out
bit/sec µs ms
600 1 667 109 225
1 200 833 54 613
2 400 417 27 306
4 800 208 13 653
9 600 104 6 827
14400 69 4 551
19200 52 3 413
28800 35 2 276
33400 30 1 962
56000 18 1 170
57600 17 1 138
200000 5 328
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
FRAME
RXRDY
RSTSTA = 1
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A break is transmitted by writing the Control Register (US_CR) with the STTBRK bit at 1. This can be performed at any
time, either while the transmitter is empty (no character in either the Shift Register or in US_THR) or when a character is
being transmitted. If a break is requested while a character is being shifted out, the character is first completed before the
TXD line is held low.
Once STTBRK command is requested further STTBRK commands are ignored until the end of the break is completed.
The break condition is removed by writing US_CR with the STPBRK bit at 1. If the STPBRK is requested before the end
of the minimum break duration (one character, including start, data, parity and stop bits), the transmitter ensures that the
break condition completes.
The transmitter considers the break as though it is a character, i.e. the STTBRK and STPBRK commands are taken in to
account only if the TXRDY bit in US_CSR is at 1 and the start of the break condition clears the TXRDY and TXEMPTY
bits as if a character is processed.
Writing US_CR with the both STTBRK and STPBRK bits at 1 can lead to an unpredictable result. All STPBRK
commands requested without a previous STTBRK command are ignored. A byte written into the Transmit Holding
Register while a break is pending, but not started, is ignored.
After the break condition, the transmitter returns the TXD line to 1 for a minimum of 12 bit times. Thus, the transmitter
ensures that the remote receiver detects correctly the end of break and the start of the next character. If the timeguard is
programmed with a value higher than 12, the TXD line is held high for the timeguard period.
After holding the TXD line for this period, the transmitter resumes normal operations.
Figure 30-16 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK) commands on the TXD
line.
Figure 30-16. Break Transmission
30.6.3.11 Receive Break
The receiver detects a break condition when all data, parity and stop bits are low. This corresponds to detecting a
framing error with data at 0x00, but FRAME remains low.
When the low stop bit is detected, the receiver asserts the RXBRK bit in US_CSR. This bit may be cleared by writing the
Control Register (US_CR) with the bit RSTSTA at 1.
An end of receive break is detected by a high level for at least 2/16 of a bit period in asynchronous operating mode or one
sample at high level in synchronous operating mode. The end of break detection also asserts the RXBRK bit.
30.6.3.12 Hardware Handshaking
The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins are used to connect with
the remote device, as shown in Figure 30-17.
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
Write
US_CR
TXRDY
TXEMPTY
STPBRK = 1
STTBRK = 1
Break Transmission End of Break
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Figure 30-17. Connection with a Remote Device for Hardware Handshaking
Setting the USART to operate with hardware handshaking is performed by writing the USART_MODE field in the Mode
Register (US_MR) to the value 0x2.
The USART behavior when hardware handshaking is enabled is the same as the behavior in standard synchronous or
asynchronous mode, except that the receiver drives the RTS pin as described below and the level on the CTS pin
modifies the behavior of the transmitter as described below. Using this mode requires using the PDC channel for
reception. The transmitter can handle hardware handshaking in any case.
Figure 30-18 shows how the receiver operates if hardware handshaking is enabled. The RTS pin is driven high if the
receiver is disabled and if the status RXBUFF (Receive Buffer Full) coming from the PDC channel is high. Normally, the
remote device does not start transmitting while its CTS pin (driven by RTS) is high. As soon as the Receiver is enabled,
the RTS falls, indicating to the remote device that it can start transmitting. Defining a new buffer to the PDC clears the
status bit RXBUFF and, as a result, asserts the pin RTS low.
Figure 30-18. Receiver Behavior when Operating with Hardware Handshaking
Figure 30-19 shows how the transmitter operates if hardware handshaking is enabled. The CTS pin disables the
transmitter. If a character is being processing, the transmitter is disabled only after the completion of the current
character and transmission of the next character happens as soon as the pin CTS falls.
Figure 30-19. Transmitter Behavior when Operating with Hardware Handshaking
30.6.4 ISO7816 Mode
The USART features an ISO7816-compatible operating mode. This mode permits interfacing with smart cards and
Security Access Modules (SAM) communicating through an ISO7816 link. Both T = 0 and T = 1 protocols defined by the
ISO7816 specification are supported.
Setting the USART in ISO7816 mode is performed by writing the USART_MODE field in the Mode Register (US_MR) to
the value 0x4 for protocol T = 0 and to the value 0x5 for protocol T = 1.
USART
TXD
CTS
Remote
Device
RXD
TXDRXD
RTS
RTS
CTS
RTS
RXBUFF
Write
US_CR
RXEN = 1
RXD RXDIS = 1
CTS
TXD
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30.6.4.1 ISO7816 Mode Overview
The ISO7816 is a half duplex communication on only one bidirectional line. The baud rate is determined by a division of
the clock provided to the remote device (see “Baud Rate Generator” on page 295).
The USART connects to a smart card as shown in Figure 30-20. The TXD line becomes bidirectional and the Baud Rate
Generator feeds the ISO7816 clock on the SCK pin. As the TXD pin becomes bidirectional, its output remains driven by
the output of the transmitter but only when the transmitter is active while its input is directed to the input of the receiver.
The USART is considered as the master of the communication as it generates the clock.
Figure 30-20. Connection of a Smart Card to the USART
When operating in ISO7816, either in T = 0 or T = 1 modes, the character format is fixed. The configuration is 8 data bits,
even parity and 1 or 2 stop bits, regardless of the values programmed in the CHRL, MODE9, PAR and CHMODE fields.
MSBF can be used to transmit LSB or MSB first. Parity Bit (PAR) can be used to transmit in normal or inverse mode.
Refer to “USART Mode Register” on page 321 and “PAR: Parity Type” on page 322.
The USART cannot operate concurrently in both receiver and transmitter modes as the communication is unidirectional
at a time. It has to be configured according to the required mode by enabling or disabling either the receiver or the
transmitter as desired. Enabling both the receiver and the transmitter at the same time in ISO7816 mode may lead to
unpredictable results.
The ISO7816 specification defines an inverse transmission forma t. Data bits of the character mu st be tran smitted on the
I/O line at their negative value. The USART does not support this format and the user has to perform an exclusive OR on
the data before writing it in the Transmit Holding Register (US_THR) or after reading it in the Receive Holding Register
(US_RHR).
30.6.4.2 Protocol T = 0
In T = 0 protocol, a character is made up of one start bit, eight data bits, one parity bit and one guard time, which lasts
two bit times. The transmitter shifts out the bits and does not drive the I/O line during the guard time.
If no parity error is detected, the I/O line remains at 1 during the guard time and the transmitter can continue with the
transmission of the next character, as shown in Figure 30-21.
If a parity error is detected by the receiver, it drives the I/O line at 0 during the guard time, as shown in Figure 30-22. This
error bit is also named NACK, for Non Acknowledge. In this case, the character lasts 1 bit time more, as the guard time
length is the same and is added to the error bit time which lasts 1 bit time.
When the USART is the receiver and it detects an error, it does not load the erroneous character in the Receive Holding
Register (US_RHR). It appropriately sets the PARE bit in the Status Register (US_SR) so that the software can handle
the error.
Figure 30-21. T = 0 Protocol without Parity Error
Smart
Card
SCK CLK
TXD I/O
USART
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Parity
Bit
Baud Rate
Clock
Start
Bit Guard
Time 1 Next
Start
Bit
Guard
Time 2
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Figure 30-22. T = 0 Protocol with Parity Error
30.6.4.3 Receive Error Counter
The USART receiver also records the total number of errors. This can be read in the Number of Error (US_NER) register.
The NB_ERRORS field can record up to 255 errors. Reading US_NER automatically clears the NB_ERRORS field.
30.6.4.4 Receive NACK Inhibit
The USART can also be configured to inhibit an error. This can be achieved by setting the INACK bit in the Mode
Register (US_MR). If INACK is at 1, no error signal is driven on the I/O line even if a parity bit is detected, but the INACK
bit is set in the Status Register (US_SR). The INACK bit can be cleared by writing the Control Reg ister (US_CR) with the
RSTNACK bit at 1.
Moreover, if INACK is set, the erroneous received character is stored in the Receive Holding Register, as if no error
occurred. However, the RXRDY bit does not raise.
30.6.4.5 Transmit Character Repetition
When the USART is transmitting a character and gets a NACK, it can automatically repeat the character before moving
on to the next one. Repetition is enabled by writing the MAX_ITERATION field in the Mode Register (US_MR) at a value
higher than 0. Each character can be transmitted up to eight times; the first transmission plus seven repetitions.
If MAX_ITERATION does not equal zero, the USART repeats the character as many times as the value loaded in
MAX_ITERATION.
When the USART repetition number reaches MAX_ITERATION, the ITERATION bit is set in the Channel Status Register
(US_CSR). If the repetition of the character is acknowledged by the receiver, th e repetitions are stopped and the iteration
counter is cleared.
The ITERATION bit in US_CSR can be cleared by writing the Control Register with the RSIT bit at 1.
30.6.4.6 Disable Successive Receive NACK
The receiver can limit the number of successive NACKs sent back to the remote transmitter. This is programmed by
setting the bit DSNACK in the Mode Register (US_MR). The maximum number of NACK transmitted is programmed in
the MAX_ITERATION field. As soon as MAX_ITERATION is reached, the character is considered as correct, an
acknowledge is sent on the line and the ITERATION bit in the Channel Status Register is set.
30.6.4.7 Protocol T = 1
When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one stop bit.
The parity is generated when transmitting and checked when receiving. Parity error detection sets the PARE bit in the
Channel Status Register (US_CSR).
30.6.5 IrDA Mode
The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the
modulator and demodulator which allows a glueless connection to the infrared transceivers, as shown in Figure 30-23.
The modulator and demodulator are compliant with the IrDA specification version 1.1 and support data transfer speeds
ranging from 2.4 Kb/s to 115.2 Kb/s.
The USART IrDA mode is enabled by setting the USART_MODE field in the Mode Register (US_MR) to the value 0x8.
The IrDA Filter Register (US_IF) allows configuring the demodulator filter. The USART transmitter and receiver operate
D0 D1 D2 D3 D4 D5 D6 D7
I/O
Parity
Bit
Baud Rate
Clock
Start
Bit Guard
Time 1 Start
Bit
Guard
Time 2 D0 D1
Error
Repetition
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in a normal asynchronous mode and all parameters are accessible. Note that the modulator and the demodulator are
activated.
Figure 30-23. Connection to IrDA Transceivers
The receiver and the transmitter must be enabled or disabled according to the direction of the transmission to be
managed.
To receive IrDA signals, the following needs to be done:
Disable TX and Enable RX
Configure the TXD pin as PIO and set it as an output at 0 (to avoid LED emission). Disable the internal pull-up
(better for power consumption).
Receive data
30.6.5.1 IrDA Modulation
For baud rates up to and including 115.2 Kbits/sec, the RZI modulation scheme is used. “0” is represented by a light
pulse of 3/16th of a bit time. Some examples of signal pulse duration are shown in Table 30-9.
Figure 30-24 shows an example of character transmission.
IrDA
Transceivers
RXD RX
TXD TX
USART
Demodulator
Modulator
Receiver
Transmitter
Table 30-9. IrDA Pulse Duration
Baud Rate Pulse Duration (3/16)
2.4 Kb/s 78.13 µs
9.6 Kb/s 19.53 µs
19.2 Kb/s 9.77 µs
38.4 Kb/s 4.88 µs
57.6 Kb/s 3.26 µs
115.2 Kb/s 1.63 µs
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Figure 30-24. IrDA Modulation
30.6.5.2 IrDA Baud Rate
Table 30-10 gives some examples of CD values, baud rate error and pulse duration. Note that the requirement on the
maximum acceptable error of ±1.87% must be met.
Bit Period Bit Period
3
16
Start
Bit Data Bits Stop
Bit
00
000
111 1
1
Transmitter
Output
TXD
Table 30-10. IrDA Baud Rate Error
Peripheral Clock Baud Rate CD Baud Rate Error Pulse Time
3 686 400 115 200 2 0.00% 1.63
20 000 000 115 200 11 1.38% 1.63
32 768 000 115 200 18 1.25% 1.63
40 000 000 115 200 22 1.38% 1.63
3 686 400 57 600 4 0.00% 3.26
20 000 000 57 600 22 1.38% 3.26
32 768 000 57 600 36 1.25% 3.26
40 000 000 57 600 43 0.93% 3.26
3 686 400 38 400 6 0.00% 4.88
20 000 000 38 400 33 1.38% 4.88
32 768 000 38 400 53 0.63% 4.88
40 000 000 38 400 65 0.16% 4.88
3 686 400 19 200 12 0.00% 9.77
20 000 000 19 200 65 0.16% 9.77
32 768 000 19 200 107 0.31% 9.77
40 000 000 19 200 130 0.16% 9.77
3 686 400 9 600 24 0.00% 19.53
20 000 000 9 600 130 0.16% 19.53
32 768 000 9 600 213 0.16% 19.53
40 000 000 9 600 260 0.16% 19.53
3 686 400 2 400 96 0.00% 78.13
20 000 000 2 400 521 0.03% 78.13
32 768 000 2 400 853 0.04% 78.13
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30.6.5.3 IrDA Demodulator
The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is loaded with the value
programmed in US_IF. When a falling edge is detected on the RXD pin, the Filter Counter starts counting down at the
Master Clock (MCK) speed. If a rising edge is detected on the RXD pin, the counter stops and is reloaded with US_IF. If
no rising edge is detected when the counter reaches 0, the input of the receiver is driven low during one bit time.
Figure 30-25 illustrates the operations of the IrDA demodulator.
Figure 30-25. IrDA Demodulator Operations
As the IrDA mode uses the same logic as the ISO7816, note that the FI_DI_RATIO field in US_FIDI must be set to a
value higher than 0 in order to assure IrDA communications operate correctly.
MCK
RXD
Receiver
Input
Pulse
Rejected
65432 61
65432 0
Pulse
Accepted
Counter
Value
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30.6.6 RS485 Mode
The USART features the RS485 mode to enable line driver control. While operating in RS485 mode, the USART
behaves as though in asynchronous or synchronous mode and configuration of all the parameters is possible. The
difference is that the RTS pin is driven high when the transmitter is operating. The behavior of the RTS pin is controlled
by the TXEMPTY bit. A typical connection of the USART to a RS485 bus is shown in Figure 30-26.
Figure 30-26. Typical Connection to a RS485 Bu s
The USART is set in RS485 mode by programming the USART_MODE field in the Mode Register (US_MR) to the value
0x1.
The RTS pin is at a level inverse to the TXEMPTY bit. Significantly, the RTS pin remains high when a timeguard is
programmed so that the line can remain driven after the last character completion. Figure 30-27 gives an example of the
RTS waveform during a character transmission when the timeguard is enabled.
Figure 30-27. Example of RTS Drive with Timeguard
USART
RTS
TXD
RXD
Differential
Bus
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit Parity
Bit Stop
Bit
Baud Rate
Clock
TG = 4
Write
US_THR
TXRDY
TXEMPTY
RTS
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30.6.7 Modem Mode
The USART features modem mode, which enables control of the signals: DTR (Data Terminal Ready), DSR (Data Set
Ready), RTS (Request to Send), CTS (Clear to Send), DCD (Data Carrier Detect) and RI (Ring Indicator). While
operating in modem mode, the USART behaves as a DTE (Data Terminal Equipment) as it drives DTR and RTS and can
detect level change on DSR, DCD, CTS and RI.
Setting the USART in modem mode is performed by writing the USART_MODE field in the Mode Register (US_MR) to
the value 0x3. While operating in modem mode the USART behaves as though in asynchronous mode and all the
parameter configurations are available.
Table 30-11 gives the correspondence of the USART signals with modem connection standards.
The control of the DTR output pin is performed by writing the Control Register (US_CR) with the DTRDIS and DTREN
bits respectively at 1. The disable command forces the corresponding pin to its inactive level, i.e. high. The enable
command forces the corresponding pin to its active level, i.e. low. RTS output pin is automatically controlled in this mode
The level changes are detected on the RI, DSR, DCD and CTS pins. If an input change is detected, the RIIC, DSRIC,
DCDIC and CTSIC bits in the Channel Status Register (US_CSR) are set respectively and can trigger an interrupt. The
status is automatically cleared when US_CSR is read. Furthermore, the CTS automatically disables the transmitter when
it is detected at its inactive state. If a character is being transmitted when the CTS rises, the character transmission is
completed before the transmitter is actually disabled.
30.6.8 Test Modes
The USART can be programmed to operate in three different test modes. The internal loopback capability allows on-
board diagnostics. In the loopback mode the USART interface pins are disconnected or not and reconfigured for
loopback internally or externally.
30.6.8.1 Normal Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD pin.
Figure 30-28. Normal Mode Configuration
Table 30-11. Circuit References
USART Pin V24 CCITT Direction
TXD 2 103 From terminal to modem
RTS 4 105 From terminal to modem
DTR 20 108.2 From terminal to modem
RXD 3 104 From modem to terminal
CTS 5 106 From terminal to modem
DSR 6 107 From terminal to modem
DCD 8 109 From terminal to modem
RI 22 125 From terminal to modem
Receiver
Transmitter
RXD
TXD
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30.6.8.2 Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it is sent to the TXD pin, as
shown in Figure 30-29. Programming the transmitter has no effect on the TXD pin. The RXD pin is still connected to the
receiver input, thus the receiver remains active.
Figure 30-29. Automatic Echo Mode Configuration
30.6.8.3 Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver, as shown in Figure 30-30.
The TXD and RXD pins are not used. The RXD pin has no effect on the receiver and the TXD pin is continuously driven
high, as in idle state.
Figure 30-30. Local Loopback Mode Configurati on
30.6.8.4 Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 30-31. The transmitter and the
receiver are disabled and have no effect. This mode allows bit-by-bit retransmission.
Figure 30-31. Remote Loopback Mode Conf iguration
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
1
Receiver
Transmitter
RXD
TXD
1
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30.7 Universal Synchronous Asynchronous Receiver Transeiver (USART) User Interface
Table 30-12. Memory Mapping
Offset Register Name Access Reset
0x0000 Control Register US_CR Write -o nl y –
0x0004 Mode Register US_MR Read-write –
0x0008 Interrupt Enable Register US_IER Write-only –
0x000C Interrupt Disable Register US_IDR Write-only –
0x0010 Interrupt Mask Register US_IMR Read-on ly 0x0
0x0014 Channel Status Register US_CSR Read-only –
0x0018 Receiver Hold ing Register US_RHR Read-only 0x0
0x001C T ransmitter Holding Register US_THR Write-only –
0x0020 Baud Rate Generator Register US_BRGR Read-write 0x0
0x0024 Receiver Time-out Register US_RTOR Read-write 0x0
0x0028 Transmitter Timeguard Register US_TTGR Read-write 0x0
0x2C - 0x3C Reserved – – –
0x0040 FI DI Ratio Register US_FIDI Read-write 0x174
0x0044 Number of Errors Register US_NER Read-only –
0x0048 Reserved – – –
0x004C IrDA Filter Register US_IF Read-write 0x0
0x5C - 0xFC Reserved – – –
0x100 - 0x128 Reserved for PDC Registers – – –
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30.7.1 USART Control Register
Name: US_CR
Access Type: Write-only
• RSTRX: Reset Receiver
0: No effect.
1: Resets the receiver.
• RSTTX: Rese t Transmitter
0: No effect.
1: Resets the transmitter.
• RXEN: Receiver Enable
0: No effect.
1: Enables the receiver, if RXDIS is 0.
• RXDIS: Receiver Dis able
0: No effect.
1: Disables the receiver.
• TXEN: Transmitter Enable
0: No effect.
1: Enables the transmitter if TXDIS is 0.
• TXDIS: Transmitter Disable
0: No effect.
1: Disables the transmitter.
• RSTSTA: Reset Status Bits
0: No effect.
1: Resets the status bits PARE, FRAME, OVRE, and RXBRK in US_CSR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––RTSDISRTSENDTRDISDTREN
15 14 13 12 11 10 9 8
RETTO RSTNACK RSTIT SENDA STTTO STPBRK STTBRK RSTSTA
76543210
TXDIS TXEN RXDIS RXEN RSTTX RSTRX – –
320
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• STTBRK: Start Break
0: No effect.
1: Starts transmission of a break after the characters present in US_THR and the Transmit Shift Register have been transmitted.
No effect if a break is already being transmitted.
• STPBRK: Stop Break
0: No effect.
1: Stops transmission of the break after a minimum of one character length and transmits a high level during 12-bit periods. No
effect if no break is being transmitted.
• STTTO: Start Time-out
0: No effect.
1: Starts waiting for a character before clocking the time-out counter. Resets the status bit TIMEOUT in US_CSR.
• SENDA: Send Address
0: No effect.
1: In Multidrop Mode only, the next character written to the US_THR is sent with the address bit set.
• RSTIT: Reset Iterations
0: No effect.
1: Resets ITERATION in US_CSR. No effect if the ISO7816 is not enabled.
• RSTNACK: Reset Non Acknowledge
0: No effect
1: Resets NACK in US_CSR.
• RETTO: Rearm Time-out
0: No effect
1: Restart Time-out
• DTREN: Data Terminal Ready Enable
0: No effect.
1: Drives the pin DTR at 0.
• DTRDIS: Data Terminal Ready Disable
0: No effect.
1: Drives the pin DTR to 1.
• RTSEN: Request to Send Enable
0: No effect.
1: Drives the pin RTS to 0.
• RTSDIS: Request to Send Disable
0: No effect.
1: Drives the pin RTS to 1.
321
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.2 USART Mode Register
Name: US_MR
Access Type: Read-write
• USART_MODE
• USCLKS: Clock Selection
• CHRL: Character Length.
31 30 29 28 27 26 25 24
– – – FILTER – MAX_ITERATION
23 22 21 20 19 18 17 16
– – DSNACK INACK OVER CLKO MODE9 MSBF
15 14 13 12 11 10 9 8
CHMODE NBSTOP PAR SYNC
76543210
CHRL USCLKS USART_MODE
USART_MODE Mode of the USART
0000Normal
0001RS485
0 0 1 0 Hardware Handshaking
0011Modem
0 1 0 0 IS07816 Protocol: T = 0
0101Reserved
0 1 1 0 IS07816 Protocol: T = 1
0111Reserved
1000IrDA
11xxReserved
USCLKS Selected Clock
00MCK
0 1 MCK/DIV (DIV = 8)
10Reserved
11SCK
CHRL Character Length
0 0 5 bits
322
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• SYNC: Synchronous Mode Select
0: USART operates in Asynchronous Mode.
1: USART operates in Synchronous Mode.
• PAR: Parity Type
• NBSTOP: Number of Stop Bits
• CHMODE: Channel Mode
• MSBF: Bit Order
0: Least Significant Bit is sent/received first.
1: Most Significant Bit is sent/received first.
• MODE9: 9-bit Character Length
0: CHRL defines character length.
1: 9-bit character length.
0 1 6 bits
1 0 7 bits
1 1 8 bits
PAR Parity Type
000Even parity
001Odd parity
0 1 0 Parity forced to 0 (Space)
0 1 1 Parity forced to 1 (Mark)
10xNo parity
1 1 x Multidrop mode
NBSTOP Asynchronous (SYNC = 0) Synchronous (SYNC = 1)
0 0 1 stop bit 1 stop bit
0 1 1.5 stop bits Reserved
1 0 2 stop bits 2 stop bits
1 1 Reserved Reserved
CHMODE Mode Description
0 0 Normal Mode
0 1 Automatic Echo. Receiver input is connected to the TXD pin.
1 0 Local Loopback. Transmitter output is connected to the Receiver Input..
1 1 Remote Loopback. RXD pin is internally connected to the TXD pin.
323
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CLKO: Clock Output Select
0: The USART does not drive the SCK pin.
1: The USART drives the SCK pin if USCLKS does not select the external clock SCK.
• OVER: Oversampling Mode
0: 16x Oversampling.
1: 8x Oversampling.
• INACK: Inhibit Non Acknowledge
0: The NACK is generated.
1: The NACK is not generated.
• DSNACK: Disable Successive NACK
0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set).
1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors generate a
NACK on the ISO line. As soon as this value is reached, no additional NACK is sent on the ISO line. The flag ITERATION is
asserted.
• MAX_ITERATION
Defines the maximum number of iterations in mode ISO7816, protocol T= 0.
• FILTER: Infrared Receive Line Filter
0: The USART does not filter the receive line.
1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority).
324
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.3 USART Interrupt Enable Register
Name: US_IER
Access Type: Write-only
• RXRDY: RXRDY Interrupt Enable
• TXRDY: TXRDY Interrupt Enable
• RXBRK: Receiver Break Interrupt Enable
• ENDRX: End of Receive Transfer Interrupt Enable
• ENDTX: End of Transmit Interrupt Enable
• OVRE: Overrun Error Interrupt Enable
• FRAME: Framing Error Interrupt Enable
• PARE: Parity Error Interrupt Enable
• TIMEOUT: Time-out Interrupt Enable
• TXEMPTY: TXEMPTY Interrupt Enable
• ITERATION: Iteration Interrupt Enable
• TXBUFE: Buffer Empty Interrupt Enable
• RXBUFF: Buffer Full Interrupt Enable
• NACK: Non Acknowledge Interrupt Enable
• RIIC: Ring Indicator Input Change Enable
• DSRIC: Data Set Ready Input Change Enable
• DCDIC: Data Carrier Detect Input Change Interrupt Enable
• CTSIC: Clear to Send Input Change Interrupt Enable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––CTSICDCDIC DSRIC RIIC
15 14 13 12 11 10 9 8
– – NACK RXBUFF TXBUFE ITERATION TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
325
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.4 USART Interrupt Disable Register
Name: US_IDR
Access Type: Write-only
• RXRDY: RXRDY Interrupt Disable
• TXRDY: TXRDY Interrupt Disable
• RXBRK: Receiver Break Interrupt Disable
• ENDRX: End of Receive Transfer Interrupt Disable
• ENDTX: End of Transmit Interrupt Disable
• OVRE: Overrun Error Interrupt Disable
• FRAME: Framing Error Interrupt Disable
• PARE: Parity Error Interrupt Disable
• TIMEOUT: Time-out Interrupt Disable
• TXEMPTY: TXEMPTY Interrupt Disable
• ITERATION: Iteration Interrupt Disable
• TXBUFE: Buffer Empty Interrupt Disable
• RXBUFF: Buffer Full Interrupt Disable
• NACK: Non Acknowledge Interrupt Disable
• RIIC: Ring Indicator Input Change Disable
• DSRIC: Data Set Ready Input Change Disable
• DCDIC: Data Carrier Detect Input Change Interrupt Disable
• CTSIC: Clear to Send Input Change Interrupt Disable
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––CTSICDCDIC DSRIC RIIC
15 14 13 12 11 10 9 8
– – NACK RXBUFF TXBUFE ITERATION TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
326
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.5 USART Interrupt Mask Register
Name: US_IMR
Access Type: Read-only
• RXRDY: RXRDY Inte rrup t Mas k
• TXRDY: TXRDY Interrupt Mask
• RXBRK: Receiver Break Int errupt Mask
• ENDRX: End of Receive Transfer Interrupt Mask
• ENDTX: End of Transmit Interrupt Mask
• OVRE: Overrun Error Interrupt Mask
• FRAME: Framing Error Interrupt Mask
• PARE: Parity Error Interrupt Mask
• TIMEOUT: Time-out Interrupt Mask
• TXEMPTY: TXEMPTY Interrupt Mask
• ITERATION: Iteration Interrupt Mask
• TXBUFE: Buffer Empty Interrupt Mask
• RXBUFF: Buffer Full Interrupt Mask
• NACK: Non Acknowledge Interrupt Mask
• RIIC: Ring Indicator Input Change Mask
• DSRIC: Data Set Ready Input Change Mask
• DCDIC: Data Carrier Detect Input Change Interrupt Mask
• CTSIC: Clear to Send Input Change Interrupt Mask
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––CTSICDCDIC DSRIC RIIC
15 14 13 12 11 10 9 8
– – NACK RXBUFF TXBUFE ITERATION TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
327
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.6 USART Channel Status Register
Name: US_CSR
Access Type: Read-only
• RXRDY: Receiver Ready
0: No complete character has been received since the last read of US_RHR or the receiver is disabled. If characters were being
received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.
1: At least one complete character has been received and US_RHR has not yet been read.
• TXRDY: Transmitter Ready
0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register, or an STTBRK command has been
requested, or the transmitter is disabled. As soon as the transmitter is enabled, TXRDY becomes 1.
1: There is no character in the US_THR.
• RXBRK: Break Received/End of Break
0: No Break received or End of Break detected since the last RSTSTA.
1: Break Received or End of Break detected since the last RSTSTA.
• ENDRX: End of Receiver Transfer
0: The End of Transfer signal from the Receive PDC channel is inactive.
1: The End of Transfer signal from the Receive PDC channel is active.
• ENDTX: End of Transmitter Transfer
0: The End of Transfer signal from the Transmit PDC channel is inactive.
1: The End of Transfer signal from the Transmit PDC channel is active.
• OVRE: Overrun Error
0: No overrun error has occurred since the last RSTSTA.
1: At least one overrun error has occurred since the last RSTSTA.
• FRAME: Framing Error
0: No stop bit has been detected low since the last RSTSTA.
1: At least one stop bit has been detected low since the last RSTSTA.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CTS DCD DSR RI CTSIC DCDIC DSRIC RIIC
15 14 13 12 11 10 9 8
– – NACK RXBUFF TXBUFE ITERATION TXEMPTY TIMEOUT
76543210
PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY
328
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• PARE: Parity Error
0: No parity error has been detected since the last RSTSTA.
1: At least one parity error has been detected since the last RSTSTA.
• TIMEOUT: Receiver Time-out
0: There has not been a time-out since the last Start Time-out command (STTTO in US_CR) or the Time-out Register is 0.
1: There has been a time-out since the last Start Time-out command (STTTO in US_CR).
• TXEMPTY: Transmitter Empty
0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.
1: There are no characters in US_THR, nor in the Transmit Shift Register.
• ITERATION: Max number of Repetitions Reached
0: Maximum number of repetitions has not been reached since the last RSIT.
1: Maximum number of repetitions has been reached since the last RSIT.
• TXBUFE: Transmission Buffer Empty
0: The signal Buffer Empty from the Transmit PDC channel is inactive.
1: The signal Buffer Empty from the Transmit PDC channel is active.
• RXBUFF: Reception Buffer Full
0: The signal Buffer Full from the Receive PDC channel is inactive.
1: The signal Buffer Full from the Receive PDC channel is active.
• NACK: Non Acknowledge
0: No Non Acknowledge has not been detected since the last RSTNACK.
1: At least one Non Acknowledge has been detected since the last RSTNACK.
• RIIC: Ring Indicator Input Change Flag
0: No input change has been detected on the RI pin since the last read of US_CSR.
1: At least one input change has been detected on the RI pin since the last read of US_CSR.
• DSRIC: Data Set Ready Input Change Flag
0: No input change has been detected on the DSR pin since the last read of US_CSR.
1: At least one input change has been detected on the DSR pin since the last read of US_CSR.
• DCDIC: Data Carrier Detect Input Change Flag
0: No input change has been detected on the DCD pin since the last read of US_CSR.
1: At least one input change has been detected on the DCD pin since the last read of US_CSR.
• CTSIC: Clear to Send Input Change Flag
0: No input change has been detected on the CTS pin since the last read of US_CSR.
1: At least one input change has been detected on the CTS pin since the last read of US_CSR.
329
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• RI: Image of RI Input
0: RI is at 0.
1: RI is at 1.
• DSR: Image of DSR Input
0: DSR is at 0
1: DSR is at 1.
• DCD: Image of DCD Input
0: DCD is at 0.
1: DCD is at 1.
• CTS: Image of CTS Input
0: CTS is at 0.
1: CTS is at 1.
330
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.7 USART Receive Holding Register
Name: US_RHR
Access Type: Read-only
• RXCHR: Received Character
Last character received if RXRDY is set.
• RXSYNH: Received Sync
0: Last Character received is a Data.
1: Last Character received is a Command.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RXSYNH ––––––RXCHR
76543210
RXCHR
331
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.8 USART Transmit Holding Register
Name: US_THR
Access Type: Write-only
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
• TXSYNH: Sync Field to be transmitted
0: The next character sent is encoded as a data. Start Frame Delimiter is DATA SYNC.
1: The next character sent is encoded as a command. Start Frame Delimiter is COMMAND SYNC.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TXSYNH ––––––TXCHR
76543210
TXCHR
332
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.9 USART Baud Rate Generator Register
Name: US_BRGR
Access Type: Read-write
• CD: Clock Divider
• FP: Fractional Part
0: Fractional divider is disabled.
1 - 7: Baudrate resolution, defined by FP x 1/8.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––– FP
15 14 13 12 11 10 9 8
CD
76543210
CD
CD
USART_MODE ≠ ISO7816 USART_MODE =
ISO7816
SYNC = 0 SYNC = 1
OVER = 0 OVER = 1
0 Baud Rate Clock Disabled
1 to 65535 Baud Rate =
Selected Clock/16/CD Baud Rate =
Selected Clock/8/CD Baud Rate =
Selected Clock /CD Baud Rate = Selected
Clock/CD/FI_DI_RATIO
333
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.10 USART Receiver Time-out Register
Name: US_RTOR
Access Type: Read-write
• TO: Time-out Value
0: The Receiver Time-out is disabled.
1 - 65535: The Receiver Time-out is enabled and the Time-out delay is TO x Bit Period.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TO
76543210
TO
334
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.11 USART Transmitter Timeguard Register
Name: US_TTGR
Access Type: Read-write
• TG: Timeguard Value
0: The Transmitter Timeguard is disabled.
1 - 255: The Transmitter timeguard is enabled and the timeguard delay is TG x Bit Period.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TG
335
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.12 USART FI DI RATIO Register
Name: US_FIDI
Access Type: Read-write
Reset Value : 0x174
• FI_DI_RATIO: FI Over DI Ratio Value
0: If ISO7816 mode is selected, the Baud Rate Generator generates no signal.
1 - 2047: If ISO7816 mode is selected, the Baud Rate is the clock provided on SCK divided by FI_DI_RATIO.
30.7.13 USART Number of Errors Register
Name: US_NER
Access Type: Read-only
• NB_ERRORS: Number of Errors
Total number of errors that occurred during an ISO7816 transfer. This register automatically clears when read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––– FI_DI_RATIO
76543210
FI_DI_RATIO
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
NB_ERRORS
336
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
30.7.14 USART IrDA FILTER Register
Name: US_IF
Access Type: Read-write
• IRDA_FILTER: IrDA Filter
Sets the filter of the IrDA demodulator.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
IRDA_FILTER
337
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31. Synchronous Serial Controller (SSC)
31.1 Overview
The Atmel Synchronous Serial Controller (SSC) provides a synchronous communication link with external devices. It
supports many serial synchronous communication protocols generally used in audio and telecom applications such as
I2S, Short Frame Sync, Long Frame Sync, etc.
The SSC contains an independent receiver and transmitter and a common clo ck divider. The receiver and the transmitter
each interface with three signals: the TD/RD signal for data, the TK/RK signal for the clock and the TF/RF signal for the
Frame Sync. The transfers can be programmed to start automatically or on different events detected on the Frame Sync
signal.
The SSC’s high-level of programmability and its two dedicated PDC channels of up to 32 bits permit a continuous high bit
rate data transfer without processor intervention.
Featuring connection to two PDC channels, the SSC permits interfacing with low processor overhead to the following:
CODEC’s in master or slave mode
DAC through dedicated serial interface, particularly I2S
Magnetic card reader
31.2 Block Diagram
Figure 31-1 . Block Diagram
SSC Interface PIO
PDC
APB Bridge
MCK
ASB
APB
TF
TK
TD
RF
RK
RD
Interrupt Control
SSC Interrupt
PMC
338
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31.3 Application Block Diagram
Figure 31-2. Applica tio n Bloc k Diag ra m
31.4 Pin Name List
31.5 Product Dependencies
31.5.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
Before using the SSC receiver, the PIO controller must be configured to dedicate the SSC receiver I/O lines to the SSC
peripheral mode.
Before using the SSC transmitter, the PIO controller must be configured to dedicate the SSC transmitter I/O lines to the
SSC peripheral mode.
31.5.2 Power Management
The SSC is not continuously clocked. The SSC interface may be clocked through the Power Management Controller
(PMC), therefore the programmer must first configure the PMC to enable the SSC clock.
31.5.3 Interrupt
The SSC interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling interrupts
requires programming the AIC before configuring the SSC.
All SSC interrupts can be enabled/disabled configuring the SSC Interrupt mask register. Each pending and unmasked
SSC interrupt will assert the SSC interrupt line. The SSC interrupt service routine can get the interrupt origin by reading
the SSC interrupt status register.
31.6 Functional Description
This chapter contains the functional description of the following: SSC Functional Block, Clock Managemen t, Data format,
Start, Transmitter, Receiver and Frame Sync.
Table 31-1. I/O Lines Description
Pin Name Pin Description Type
RF Receiver Frame Synchro Input/Output
RK Receiver Clock Input/Output
RD Receiver Data Input
TF Transmitter Frame Synchro Input/Output
TK Transmitter Clock Input/Output
TD Transmitter Data Output
Interrupt
Management
Power
Management Test
Management
SSC
Serial AUDIO
OS or RTOS Driver
Codec Frame
Management Line Interface
Time Slot
Management
339
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
The receiver and transmitter operate separately. However, they can work synchronously by programming the receiver to
use the transmit clock and/or to start a data transfer when transmission starts. Alternatively, this can be done by
programming the transmitter to use the receive clock and/or to start a data transfer when reception starts. The transmitter
and the receiver can be programmed to operate with the clock signals provided on either the TK or RK pins. This allows
the SSC to support many slave-mode data transfers. The maximum clock speed allowed on the TK and RK pins is the
master clock divided by 2.
Figure 31-3. SSC Functional Block Diagram
31.6.1 Clock Management
The transmitter clock can be generated by:
an external clock received on the TK I/O pad
the receiver clock
the internal clock divider
The receiver clock can be generated by:
an external clock received on the RK I/O pad
the transmitter clock
the internal clock divider
Interrupt Control
AIC
User
Interface
APB
MCK
Receive Clock
Controller
Start
Selector
TX Clock
RK Input
RF
TF
Clock Output
Controller
Frame Sync
Controller
Transmit Clock
Controller
Transmit Shift Register
Start
Selector
Transmit Sync
Holding Register
Transmit Holding
Register
Load Shift
RX clock
TX clock
TK Input
TF
TX PDC
RF
RD
RF
RK
Clock Output
Controller
Frame Sync
Controller
Receive Shift Register
Receive Sync
Holding Register
Receive Holding
Register
Load Shift
TD
TF
TK
RX Clock
RX PDC
Receiver
PDC
Transmitter
Clock
Divider
340
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Furthermore, the transmitter block can generate an external clock on the TK I/O pad, and the receiver block can generate
an external clock on the RK I/O pad.
This allows the SSC to support many Master and Slave Mode data transfers.
31.6.1.1 Clock Divider
Figure 31-4. Divided Clock Block Diagram
The Master Clock divider is determined by the 12-bit field DIV counter and comparator (so its maximal value is 4095) in
the Clock Mode Register SSC_CMR, allowing a Master Clock division by up to 8190. The Divided Clock is provided to
both the Receiver and Transmitter. When this field is programmed to 0, the Clock Divider is not used and remains
inactive.
When DIV is set to a value equal to or greater than 1, the Divided Clock has a frequency of Master Clock divided by 2
times DIV. Each level of the Divided Clock has a duration of the Master Clock multiplied by DIV. This ensures a 50% duty
cycle for the Divided Clock regardless of whether the DIV value is even or odd.
Figure 31-5. Divided Clock Gen e ra tio n
31.6.1.2 Transmitter Clock Management
The transmitter clock is generated from the receiver clock or the divider clock or an external clock scanned on the TK I/O
pad. The transmitter clock is selected by the CKS field in SSC_TCMR (Transmit Clock Mode Register). Transmit Clock
can be inverted independently by the CKI bits in SSC_TCMR.
The transmitter can also drive the TK I/O pad continuously or be limited to the actual data transfer. The clock output is
configured by the SSC_TCMR register. The Transmit Clock Inversion (CKI) bits have no effect on the clock outputs.
MCK
Divided Clock
Clock Divider
/ 2 12-bit Counter
SSC_CMR
Master Clock
Divided Clock
DIV = 1
Master Clock
Divided Clock
DIV = 3
Divided Clock Frequency = MCK/2
Divided Clock Frequency = MCK/6
Table 31-2 .
Maximum Minimum
MCK / 2 MCK / 8190
341
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Programming the TCMR register to select TK pin (CKS field) and at the same time Continuous Transmit Clock (CKO
field) might lead to unpredictable results.
Figure 31-6. Transmitter Clock Ma na ge me nt
31.6.1.3 Receiver Clock Management
The receiver clock is generated from the transmitter clock or the divider clock or an external clock scanned on the RK I/O
pad. The Receive Clock is selected by the CKS field in SSC_RCMR (Receive Clock Mode Register). Receive Clocks can
be inverted independently by the CKI bits in SSC_RCMR.
The receiver can also drive the RK I/O pad continuously or be limited to the actual data transfer. The clock output is
configured by the SSC_RCMR register. The Receive Clock Inversion (CKI) bits have no effect on the clock outputs.
Programming the RCMR register to select RK pin (CKS field) and at the same time Continuous Receive Clock (CKO
field) can lead to unpredictable results.
Figure 31-7. Receiver Cl ock Management
31.6.1.4 Serial Clock Ratio Considerations
The Transmitter and the Receiver can be programmed to operate with the clock signals provided on either the TK or RK
pins. This allows the SSC to support many slave-mode data transfers. In this case, the maximum clock speed allowed on
the RK pin is:
Master Clock divided by 2 if Receiver Frame Synchro is input
Master Clock divided by 3 if Receiver Frame Synchro is output
In addition, the maximum clock speed allowed on the TK pin is:
Master Clock divided by 6 if Transmit Frame Synchro is input
Master Clock divided by 2 if Transmit Frame Synchro is output
31.6.2 Transmitter Operations
A transmitted frame is triggered by a start event and can be followed by synchronization data before data transmission.
The start event is configured by setting the Transmit Clock Mode Register (SSC_TCMR). See “Start” on page 343.
The frame synchronization is configured setting the Transmit Frame Mode Register (SSC_TFMR). See “Frame Sync” on
page 345.
Receiver Clock
Divider Clock Transmitter Clock
SSC_TCMR.CKI
SSC_TCMR.CKS
TK
SSC_TCMR.CKO
1
0
TK
Transmitter Clock
Divider Clock Receiver Clock
SSC_RCMR.CKI
SSC_RCMR.CKS
RK
SSC_RCMR.CKO
1
0
RK
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To transmit data, the transmitter uses a shift register clocked by the transmitter clock signal and the start mode selected
in the SSC_TCMR. Data is written by the application to the SSC_THR register then transferred to the shift register
according to the data format selected.
When both the SSC_THR and the transmit shift register are empty, the status flag TXEMPTY is set in SSC_SR. When
the Transmit Holding register is transferred in the Transmit shift register, the status flag TXRDY is set in SSC_SR and
additional data can be loaded in the holding register.
Figure 31-8. Transmitter Block Dia gram
31.6.3 Receiver Operations
A received frame is triggered by a start event and can be followed by synchronization data before data transmission.
The start event is configured setting the Receive Clock Mode Register (SSC_RCMR). See “Start” on page 343.
The frame synchronization is configured setting the Receive Frame Mode Register (SSC_RFMR). See “Frame Sync” on
page 345.
The receiver uses a shift register clocked by the receiver clock signal and the start mode selected in the SSC_RCMR.
The data is transferred from the shift register depending on the data format selected.
When the receiver shift register is full, the SSC transfers this data in the holding register, the status flag RXRDY is set in
SSC_SR and the data can be read in the receiver holding register. If another transfer occurs before read of the RHR
register, the status flag OVERUN is set in SSC_SR and the receiver shift register is transferred in the RHR register.
Transmit Shift Register
Start
Selector
SSC_TSHRSSC_THR
Transmitter Clock
TD
SSC_TFMR.FSLENSSC_TFMR.DATLEN
SSC_CR.TXEN
SSC_CR.TXDIS
SSC_TCMR.STTDLY
SSC_TFMR.FSDEN
SSC_TFMR.DATNB
SSC_SR.TXEN
SSC_TFMR.DATDEF
SSC_TFMR.MSBF
SSC_TCMR.STTDLY
SSC_TFMR.FSDEN
0
1
10
RF TF
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Figure 31-9. Receiver Block Diagram
31.6.4 Start
The transmitter and receiver can both be programmed to start their operations when an event occurs, respectively in the
Transmit Start Selection (START) field of SSC_TCMR and in the Receive Start Selection (START) field of SSC_RCMR.
Under the following conditions the start event is independently programmable:
Continuous. In this case, the transmission start s as soon as a word is written in SSC_THR and the reception st art s
as soon as the Receiver is enabled.
Synchronously with the transmitter/receiver
On detection of a falling/rising edge on TF/RF
On detection of a low level/high level on TF/RF
On detection of a level change or an edge on TF/RF
A start can be programmed in the same manner on either side of the Transmit/Receive Clock Register (RCMR/TCMR).
Thus, the start could be on TF (Transmit) or RF (Receive).
Moreover, the Receiver can start when data is detected in the bit stream with the Compare Functions.
Detection on TF/RF input/output is done by the field FSOS of the Transmit/Receive Frame Mode Register
(TFMR/RFMR).
Receive Shift Register
Start
Selector
SSC_RHRSSC_RSHR
Receiver Clock RD
SSC_RFMR.FSLEN SSC_RFMR.DATLEN
RF
SSC_CR.RXEN
SSC_CR.RXDIS
SSC_SR.RXEN
SSC_RFMR.MSBF
SSC_RCMR.STTDLY
SSC_RFMR.DATNB
TF
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Figure 31-10. Transmit Start Mode
Figure 31-11. Receive Pulse/Edge Start Modes
X
TK
TF
(Input)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
TD
(Output)
XBOB1
XBO B1
BO B1
BO B1
BO B1BO B1
BO B1B1
BO
X
X
X
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
Start = Falling Edge on TF
Start = Rising Edge on TF
Start = Low Level on TF
Start = High Level on TF
Start = Any Edge on TF
Start = Level Change on TF
X
RK
RF
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
RD
(Input)
XBOB1
XBO B1
BO B1
BO B1
BO B1BO B1
BO B1B1
BO
X
X
X
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
STTDLY
Start = Falling Edge on RF
Start = Rising Edge on RF
Start = Low Level on RF
Start = High Level on RF
Start = Any Edge on RF
Start = Level Change on RF
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31.6.5 Frame Sync
The Transmitter and Receiver Frame Sync pins, TF and RF, can be programmed to generate different kinds of frame
synchronization signals. The Frame Sync Output Selection (FSOS) field in the Receive Frame Mode Register
(SSC_RFMR) and in the Transmit Frame Mode Register (SSC_TFMR) are used to select the required waveform.
Programmable low or high levels during data transfer are supported.
Programmable high levels before the start of data transfers or toggling are also supported.
If a pulse waveform is selected, the Frame Sync Length (FSLEN) field in SSC_RFMR and SSC_TFMR programs the
length of the pulse, from 1 bit time up to 16 bit time.
The periodicity of the Receive and Transmit Frame Sync pulse output can be programmed through the Period Divider
Selection (PERIOD) field in SSC_RCMR and SSC_TCMR.
31.6.5.1 Frame Sync Data
Frame Sync Data transmits or receives a specific tag during the Frame Sync signal.
During the Frame Sync signal, the Receiver can sample the RD line and store the data in the Receive Sync Holding
Register and the transmitter can transfer Transmit Sync Holding Register in the Shifter Register. The data length to be
sampled/shifted out during the Frame Sync signal is programmed by the FSLEN field in SSC_RFMR/SSC_TFMR and
has a maximum value of 16.
Concerning the Receive Frame Sync Data operation, if the Frame Sync Length is equal to or lower than the delay
between the start event and the actual data reception, the data sampling operation is performed in the Receive Sync
Holding Register through the Receive Shift Register.
The Transmit Frame Sync Operation is performed by the transmitter only if the bit Frame Sync Data Enable (FSDEN) in
SSC_TFMR is set. If the Frame Sync length is equal to or lower than the delay between the start event and the actual
data transmission, the normal transmission has priority and the data contained in the Transmit Sync Holding Register is
transferred in the Transmit Register, then shifted out.
31.6.5.2 Frame Sync Edge Detection
The Frame Sync Edge detection is programmed by the FSEDGE field in SSC_RFMR/SSC_TFMR. This sets the
corresponding flags RXSYN/TXSYN in the SSC Status Register (SSC_SR) on frame synchro edge detection (signals
RF/TF).
31.6.6 Receive Compare Modes
Figure 31-12. Receive Compare Modes
31.6.6.1 Compare Functions
Length of the comparison patterns (Compare 0, Compare 1) and thus the number of bits they are compared to is defined
by FSLEN, but with a maximum value of 16 bits. Comparison is always done by comparing the last bits received with the
comparison pattern. Compare 0 can be one start event of the Receiver. In this case, the receiver compares at each new
sample the last bits received at the Compare 0 pattern contained in the Compare 0 Register (SSC_RC0R). When this
start event is selected, the user can program the Receiver to start a new data transfer either by writing a new Compare 0,
or by receiving continuously until Compare 1 occurs. This selectio is done with the bit (STOP) in SSC_RCMR.
CMP0 CMP3
CMP2
CMP1 Ignored B0 B2
B1
Start
RK
RD
(Input)
FSLEN
Up to 16 Bits
(4 in This Example)
STDLY DATLEN
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31.6.7 Data Format
The data framing format of both the transmitter and the receiver are programmable through the Transmitter Frame Mode
Register (SSC_TFMR) and the Receiver Frame Mode Register (SSC_RFMR). In either case, the user can independently
select:
the event that starts the data transfer (START)
the delay in number of bit periods between the start event and the first data bit (STTDLY)
the length of the data (DATLEN)
the number of data to be transferred for each start event (DATNB).
the length of synchronization transferred for each start event (FSLEN)
the bit sense: most or lowest significant bit first (MSBF).
Additionally, the transmitter can be used to transfer synchronization and select the level driven on the TD pin while not in
data transfer operation. This is done respectively by the Frame Sync Data Enable (FSDEN) and by the Data Default
Value (DATDEF) bits in SSC_TFMR.
347
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Figure 31-13. Transmit and Receive Frame Format in Edge/Pulse Start Modes
Note: 1. Example of input on falling edge of TF/RF.
Figure 31-14. Transmit Frame Format in Continuous Mode
Note: 1. STTDLY is set to 0. In this example, SSC_THR is loaded twice. FSDEN value has no effect on the transmis-
sion. SyncData cannot be output in continuous mode.
Table 31-3. Data Frame Registers
Transmitter Receiver Field Length Comment
SSC_TFMR SSC_RFMR DATLEN Up to 32 Size of word
SSC_TFMR SSC_RFMR DATNB Up to 16 Number of words transmitted in frame
SSC_TFMR SSC_RFMR MSBF Most significant bit first
SSC_TFMR SSC_RFMR FSLEN Up to 16 Size of Synchro data register
SSC_TFMR DATDEF 0 or 1 Data default value ended
SSC_TFMR FSDEN Enable send SSC_TSHR
SSC_TCMR SSC_RCMR PERIOD Up to 512 Frame size
SSC_TCMR SSC_RCMR STTDLY Up to 255 Size of transmit start delay
Sync Data
Default
STTDLY
Sync Data Ignored
RD
Default
Data
DATLEN
Data
Data
Data
DATLEN
Data
Data Default
Default
Ignored
Sync Data
Sync Data
FSLEN
TF/RF
(1)
Start
Start
From SSC_TSHR From SSC_THR
From SSC_THR
From SSC_THR
From SSC_THR
To SSC_RHR To SSC_RHRTo SSC_RSHR
TD
(If FSDEN = 0)
TD
(If FSDEN = 1)
DATNB
PERIOD
FromDATDEF FromDATDEF
From DATDEF From DATDEF
DATLEN
Data
DATLEN
Data Default
Start
From SSC_THR From SSC_THR
TD
Start: 1. TXEMPTY set to 1
2. Write into the SSC_THR
348
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Figure 31-15. Receive Frame Format in Continuous Mode
Note: 1. STTDLY is set to 0.
31.6.8 Loop Mode
The receiver can be programmed to receive transmissions from the transmitter. This is done by setting the Loop Mode
(LOOP) bit in SSC_RFMR. In this case, RD is connected to TD, RF is connected to TF and RK is connected to TK.
31.6.9 Interrupt
Most bits in SSC_SR have a corresponding bit in interrupt management registers.
The SSC can be programmed to generate an interrupt when it detects an event. The interrupt is controlled by writing
SSC_IER (Interrupt Enable Register) and SSC_IDR (Interrupt Disable Register) These registers enable and disable,
respectively, the corresponding interrupt by setting and clearing the corresponding bit in SSC_IMR (Interrupt Mask
Register), which controls the generation of interrupts by asserting the SSC interrupt line connected to the AIC.
Figure 31-16. Interrupt Block Diagram
Data
DATLEN
Data
DATLEN
Start = Enable Receiver
To SSC_RHR To SSC_RHR
RD
SSC_IMR
PDC
Interrupt
Control SSC Interrupt
Set
RXRDY
OVRUN
RXSYNC
Receiver
Transmitter
TXRDY
TXEMPTY
TXSYNC
TXBUFE
ENDTX
RXBUFF
ENDRX
Clear
SSC_IER SSC_IDR
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31.7 SSC Application Examples
The SSC can support several serial communication modes used in audio or high speed serial links. Some standard
applications are shown in the following figures. All serial link applications supported by the SSC are not listed here.
Figure 31-17. Audio Application Block Diagram
Figure 31-18. Codec Applica tio n Bloc k Dia gra m
SSC
RK
RF
RD
TD
TF
TK Clock SCK
Word Select WS
Data SD
I2S
RECEIVER
Clock SCK
Word Select WS
Data SD
Right Channel
Left Channel
MSB MSB
LSB
SSC
RK
RF
RD
TD
TF
TK Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data In
CODEC
Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data In
First Time Slot
Dstart Dend
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Figure 31-19. Time Slot Application Block Diagram
SSC
RK
RF
RD
TD
TF
TK SCLK
FSYNC
Data Out
Data in
CODEC
First
Time Slot
Serial Data Clock (SCLK)
Frame sync (FSYNC)
Serial Data Out
Serial Data in
CODEC
Second
Time Slot
First Time Slot Second Time Slot
Dstart Dend
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31.8 Synchronous Serial Controller (SSC) User Interface
Table 31-4. Regist er Mapping
Offset Register Name Access Reset
0x0 Control Register SSC_CR Write –
0x4 Clock Mode Register SSC_CMR Read-write 0x0
0x8 Reserved – – –
0xC Reserved – – –
0x10 Receive Clock Mode Register SSC_RCMR Read-write 0x0
0x14 Receive Frame Mode Register SSC_RFMR Read-write 0x0
0x18 Transmit Clock Mode Register SSC_TCMR Read-write 0x0
0x1C Tr ansmit Frame Mode Register SSC_TFMR Read-write 0x0
0x20 Receive Holding Register SSC_RHR Read 0x0
0x24 Transmit Holding Register SSC_THR Write –
0x28 Reserved – – –
0x2C Reserved – – –
0x30 Receive Sync. Holding Register SSC_RSHR Read 0x0
0x34 Transmit Sync. Holding Register SSC_TSHR Read-write 0x0
0x38 Receive Compare 0 Register SSC_RC0R Read-write 0x0
0x3C Receive Compare 1 Register SSC_RC1R Read-write 0x0
0x40 Status Register SSC_SR Read 0x000000CC
0x44 Interrupt Enable Register SSC_IER Write –
0x48 Interrupt Disable Register SSC_IDR Write –
0x4C Interrupt Mask Register SSC_IMR Read 0x0
0x50-0xFC Reserved – – –
0x100- 0x124 Reserved for Peripheral Data Controller (PDC) – – –
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31.8.1 SSC Control Register
Name: SSC_CR
Access Type: Write-only
• RXEN: Recei ve Enable
0: No effect.
1: Enables Receive if RXDIS is not set.
• RXDIS: Receiv e Dis a ble
0: No effect.
1: Disables Receive. If a character is currently being received, disables at end of current character reception.
• TXEN: Transmit Enable
0: No effect.
1: Enables Transmit if TXDIS is not set.
• TXDIS: Transmit Disable
0: No effect.
1: Disables Transmit. If a character is currently being transmitted, disables at end of current character transmission.
• SWRST: Software Reset
0: No effect.
1: Performs a software reset. Has priority on any other bit in SSC_CR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
SWRST–––––TXDISTXEN
76543210
––––––RXDISRXEN
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31.8.2 SSC Clock Mode Register
Name: SSC_CMR
Access Type: Read-write
• DIV: Clock Divider
0: The Clock Divider is not active.
Any Other Value: The Divided Clock equals the Master Clock divided by 2 times DIV. The maximum bit rate is MCK/2. The mini-
mum bit rate is MCK/2 x 4095 = MCK/8190.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––– DIV
76543210
DIV
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31.8.3 SSC Rece iv e Clo c k Mod e Reg ist e r
Name: SSC_RCMR
Access Type: Read-write
• CKS: Receive Clock Selection
• CKO: Receive Clock Output Mode Selection
• CKI: Receive Clock Inversion
0: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock falling edge. The Frame Sync signal output is
shifted out on Receive Clock rising edge.
1: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock rising edge. The Frame Sync signal output is
shifted out on Receive Clock falling edge.
CKI affects only the Receive Clock and not the output clock signal.
31 30 29 28 27 26 25 24
PERIOD
23 22 21 20 19 18 17 16
STTDLY
15 14 13 12 11 10 9 8
– – – STOP START
76543210
CKG CKI CKO CKS
CKS Selected Receive Clock
0x0 Divided Clock
0x1 TK Clock signal
0x2 RK pin
0x3 Reserved
CKO Receive Clock Output Mode RK pin
0x0 None Input-only
0x1 Continuous Receive Clock Output
0x2 Receive Clock only during data transfers Output
0x3-0x7 Reserved
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• CKG: Receive Clock Gating Selection
• START: Receive Start Selection
• STOP: Receive Stop Selection
0: After completion of a data transfer when starting with a Compare 0, the receiver stops the data transfer and waits for a
new compare 0.
1: After starting a receive with a Compare 0, the receiver operates in a continuous mode until a Compare 1 is detected.
• STTDLY: Receive Start Delay
If STTDLY is not 0, a delay of STTDLY clock cycles is inserted between the start event and the actual start of reception. When the
Receiver is programmed to start synchronously with the Transmitter, the delay is also applied.
Note: It is very important that STTDLY be set carefully. If STTDLY must be set, it should be done in relation to TAG (Receive Sync
Data) reception.
• PERIOD: Receive Period Divider Selection
This field selects the divider to apply to the selected Receive Clock in order to generate a new Frame Sync Signal. If 0, no
PERIOD signal is generated. If not 0, a PERIOD signal is generated each 2 x (PERIOD+1) Receive Clock.
CKG Receive Clock Gating
0x0 None, continuous clock
0x1 Receive Clock enabled only if RF Low
0x2 Receive Clock enabled only if RF High
0x3 Reserved
START Receive Start
0x0 Continuous, as soon as the receiver is enabled, and immediately after the end of
transfer of the previous data.
0x1 Transmit start
0x2 Detection of a low level on RF signal
0x3 Detection of a high level on RF signal
0x4 Detection of a falling edge on RF sig nal
0x5 Detection of a rising edge on RF signal
0x6 Detection of any level change on RF signal
0x7 Detection of any edge on RF signal
0x8 Compare 0
0x9-0xF Reserved
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31.8.4 SSC Receive Frame Mode Register
Name: SSC_RFMR
Access Type: Read-write
• DATLEN: Data Length
0: Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the PDC2
assigned to the Receiver. If DATLEN is lower or equal to 7, data transfers are in bytes. If DATLEN is between 8 and 15 (included),
half-words are transferred, and for any other value, 32-bit words are transferred.
• LOOP: Loop Mode
0: Normal operating mode.
1: RD is driven by TD, RF is driven by TF and TK drives RK.
• MSBF: Most Significant Bit First
0: The lowest significant bit of the data register is sampled first in the bit stream.
1: The most significant bit of the data register is sampled first in the bit stream.
• DATNB: Data Number per Frame
This field defines the number of data words to be received after each transfer start, which is equal to (DATNB + 1).
• FSLEN: Receive Frame Sync Length
This field defines the length of the Receive Frame Sync Signal and the number of bits sampled and stored in the Receive Sync
Data Register. When this mode is selected by the START field in the Receive Clock Mode Register, it also determines the length
of the sampled data to be compared to the Compare 0 or Compare 1 register.
Pulse length is equal to (FSLEN + 1) Receive Clock periods. Thus, if FSLEN is 0, the Receive Frame Sync signal is generated
during one Receive Clock period.
31 30 29 28 27 26 25 24
–––––––FSEDGE
23 22 21 20 19 18 17 16
– FSOS FSLEN
15 14 13 12 11 10 9 8
–––– DATNB
76543210
MSBF – LOOP DATLEN
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• FSOS: Receive Frame Sync Output Selection
• FSEDGE: Frame Sync Edge Detection
Determines which edge on Frame Sync will generate the interrupt RXSYN in the SSC Status Register.
FSOS Selected Receive Fr ame Sync Signal RF Pin
0x0 None Input-only
0x1 Negative Pulse Output
0x2 Positive Pulse Output
0x3 Driven Low during data transfer Output
0x4 Driven High during data transfer Output
0x5 Toggling at each start of data transfer Output
0x6-0x7 Reserved Undefined
FSEDGE Frame Sync Edge Detection
0x0 Positive Edge Detection
0x1 Negative Edge Detection
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31.8.5 SSC Transmit Clock Mode Register
Name: SSC_TCMR
Access Type: Read-write
• CKS: Transmit Clock Selection
• CKO: Transmit Clock Output Mode Selection
• CKI: Transmit Clock Inversion
0: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock falling edge. The Frame sync signal input is
sampled on Transmit clock rising edge.
1: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock rising edge. The Frame sync signal input is
sampled on Transmit clock falling edge.
CKI affects only the Transmit Clock and not the output clock signal.
31 30 29 28 27 26 25 24
PERIOD
23 22 21 20 19 18 17 16
STTDLY
15 14 13 12 11 10 9 8
–––– START
76543210
CKG CKI CKO CKS
CKS Selected Transmit Clock
0x0 Divided Clock
0x1 RK Clock signal
0x2 TK Pin
0x3 Reserved
CKO Transmit Clock Output Mode TK pin
0x0 None Input-only
0x1 Continuous Transmit Clock Output
0x2 Tr ansmit Clock only during data transfers Output
0x3-0x7 Reserved
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• CKG: Transmit Clock Gating Selection
• START: Transmit Start Selection
• STTDLY: Transmit Start Delay
If STTDLY is not 0, a delay of STTDLY clock cycles is inserted between the start event and the actual start of transmission of
data. When the Transmitter is programmed to start synchronously with the Receiver, the delay is also applied.
Note: STTDLY must be set carefully. If STTDLY is too short in respect to TAG (Transmit Sync Data) emission, data is emitted
instead of the end of TAG.
• PERIOD: Transmit Period Divider Selectio n
This field selects the divider to apply to the selected Transmit Clock to generate a new Frame Sync Signal. If 0, no period signal is
generated. If not 0, a period signal is generated at each 2 x (PERIOD+1) Transmit Clock.
CKG Transmit Clock Gating
0x0 None, continuous clock
0x1 Tr ansmit Clock enabled only if TF Low
0x2 Tr ansmit Clock enabled only if TF High
0x3 Reserved
START Transmit Start
0x0 Continuous, as soon as a word is written in the SSC_THR Register (if Transmit is enabled), and
immediately after the end of transfer of the previous data.
0x1 Receive start
0x2 Detection of a low level on TF signal
0x3 Detection of a high level on TF signa l
0x4 Detection of a falling edge on TF signal
0x5 Detection of a rising edge on TF signal
0x6 Detection of any level change on TF signal
0x7 Detection of any edge on TF signal
0x8 - 0xF Reserved
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31.8.6 SSC Transmit Frame Mode Register
Name: SSC_TFMR
Access Type: Read-write
• DATLEN: Data Length
0: Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the PDC2
assigned to the Transmit. If DATLEN is lower or equal to 7, data transfers are bytes, if DATLEN is between 8 and 15 (included),
half-words are transferred, and for any other value, 32-bit words are transferred.
• DATDEF: Data Default Value
This bit defines the level driven on the TD pin while out of transmission. Note that if the pin is defined as multi-drive by the PIO
Controller, the pin is enabled only if the SCC TD output is 1.
• MSBF: Most Significant Bit First
0: The lowest significant bit of the data register is shifted out first in the bit stream.
1: The most significant bit of the data register is shifted out first in the bit stream.
• DATNB: Data Number per frame
This field defines the number of data words to be transferred after each transfer start, which is equal to (DATNB +1).
• FSLEN: Transmit Frame Sync Lengt h
This field defines the length of the Transmit Frame Sync signal and the number of bits shifted out from the Transmit Sync Data
Register if FSDEN is 1.
Pulse length is equal to (FSLEN + 1) Transmit Clock periods, i.e., the pulse length can range from 1 to 16 Transmit Clock periods.
If FSLEN is 0, the Transmit Frame Sync signal is generated during one Transmit Clock period.
31 30 29 28 27 26 25 24
–––––––FSEDGE
23 22 21 20 19 18 17 16
FSDEN FSOS FSLEN
15 14 13 12 11 10 9 8
–––– DATNB
76543210
MSBF – DATDEF DATLEN
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• FSOS: Transmit Frame Sync Output Selection
• FSDEN: Frame Sync Data Enable
0: The TD line is driven with the default value during the Transmit Frame Sync signal.
1: SSC_TSHR value is shifted out during the transmission of the Transmit Frame Sync signal.
• FSEDGE: Frame Sync Edge Detection
Determines which edge on frame sync will generate the interrupt TXSYN (Status Register).
FSOS Selected Transmit Frame Sync Signal TF Pin
0x0 None Input-only
0x1 Negative Pulse Output
0x2 Positive Pulse Output
0x3 Driven Low during data transfer Output
0x4 Driven High during data transfer Output
0x5 Toggling at each start of data transfer Output
0x6-0x7 Reserved Undefined
FSEDGE Frame Sync Edge Detection
0x0 Positive Edge Detection
0x1 Negative Edge Detection
362
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6120K–ATARM–11-Feb-14
31.8.7 SSC Receive Holding Register
Name: SSC_RHR
Access Type: Read-only
• RDAT : Receive Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_RFMR.
31.8.8 SSC Transmit Holding Register
Name: SSC_THR
Access Type: Write-only
• TDAT: Transmit Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_TFMR.
31 30 29 28 27 26 25 24
RDAT
23 22 21 20 19 18 17 16
RDAT
15 14 13 12 11 10 9 8
RDAT
76543210
RDAT
31 30 29 28 27 26 25 24
TDAT
23 22 21 20 19 18 17 16
TDAT
15 14 13 12 11 10 9 8
TDAT
76543210
TDAT
363
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6120K–ATARM–11-Feb-14
31.8.9 SSC Receive Synchronization Holding Register
Name: SSC_RSHR
Access Type: Read-only
• RSDAT: Receive Synchronization Data
31.8.10 SSC Transmit Synchronization Holding Register
Name: SSC_TSHR
Access Type: Read-write
• TSDAT: Transmit Synchronization Data
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RSDAT
76543210
RSDAT
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TSDAT
76543210
TSDAT
364
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31.8.11 SSC Receive Compare 0 Register
Name: SSC_RC0R
Access Type: Read-write
• CP0: Receive Comp are Data 0
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CP0
76543210
CP0
365
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31.8.12 SSC Receive Compare 1 Register
Name: SSC_RC1R
Access Type: Read-write
• CP1: Receive Comp are Data 1
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CP1
76543210
CP1
366
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31.8.13 SSC Status Regi st er
Name: SSC_SR
Access Type: Read-only
• TXRDY: Transmit Ready
0: Data has been loaded in SSC_THR and is waiting to be loaded in the Transmit Shift Register (TSR).
1: SSC_THR is empty.
• TXEMPTY: Transmit Empty
0: Data remains in SSC_THR or is currently transmitted from TSR.
1: Last data written in SSC_THR has been loaded in TSR and last data loaded in TSR has been transmitted.
• ENDTX: End of Transmission
0: The register SSC_TCR has not reached 0 since the last write in SSC_TCR or SSC_TNCR.
1: The register SSC_TCR has reached 0 since the last write in SSC_TCR or SSC_TNCR.
• TXBUFE: Transmit Buffer Empty
0: SSC_TCR or SSC_TNCR have a value other than 0.
1: Both SSC_TCR and SSC_TNCR have a value of 0.
• RXRDY: Receive Re ady
0: SSC_RHR is empty.
1: Data has been received and loaded in SSC_RHR.
• OVRUN: Receive Overrun
0: No data has been loaded in SSC_RHR while previous data has not been read since the last read of the Status Register.
1: Data has been loaded in SSC_RHR while previous data has not yet been read since the last read of the Status Register.
• ENDRX: End of Reception
0: Data is written on the Receive Counter Register or Receive Next Counter Register.
1: End of PDC transfer when Receive Counter Register has arrived at zero.
• RXBUFF: Receive Buffer Full
0: SSC_RCR or SSC_RNCR have a value other than 0.
1: Both SSC_RCR and SSC_RNCR have a value of 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––RXENTXEN
15 14 13 12 11 10 9 8
––––RXSYNTXSYN CP1 CP0
76543210
RXBUFF ENDRX OVRUN RXRDY TXBUFE ENDTX TXEMPTY TXRDY
367
SAM7X Series [DATASHEET]
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•CP0: Compare 0
0: A compare 0 has not occurred since the last read of the Status Register.
1: A compare 0 has occurred since the last read of the Status Register.
•CP1: Compare 1
0: A compare 1 has not occurred since the last read of the Status Register.
1: A compare 1 has occurred since the last read of the Status Register.
• TXSYN: Transmit Sync
0: A Tx Sync has not occurred since the last read of the Status Register.
1: A Tx Sync has occurred since the last read of the Status Register.
• RXSYN: Receive Sync
0: An Rx Sync has not occurred since the last read of the Status Register.
1: An Rx Sync has occurred since the last read of the Status Register.
• TXEN: Transmit Enable
0: Transmit is disabled.
1: Transmit is enabled.
• RXEN: Recei ve Enable
0: Receive is disabled.
1: Receive is enabled.
368
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31.8.14 SSC Interrupt Enable Register
Name: SSC_IER
Access Type: Write-only
• TXRDY: Transmit Ready Interrupt Enable
0: No effect.
1: Enables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Enable
0: No effect.
1: Enables the Transmit Empty Interrupt.
• ENDTX: End of Transmission Interrupt Enable
0: No effect.
1: Enables the End of Transmission Interrupt.
• TXBUFE: Transmit Buffer Empty Interrupt Enable
0: No effect.
1: Enables the Transmit Buffer Empty Interrupt
• RXRDY: Receiv e Re ady Interru pt Ena ble
0: No effect.
1: Enables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Enable
0: No effect.
1: Enables the Receive Overrun Interrupt.
• ENDRX: End of Reception Interrupt Enable
0: No effect.
1: Enables the End of Reception Interrupt.
• RXBUFF: Receive Buffer Full Interrupt Enable
0: No effect.
1: Enables the Receive Buffer Full Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYNTXSYN CP1 CP0
76543210
RXBUFF ENDRX OVRUN RXRDY TXBUFE ENDTX TXEMPTY TXRDY
369
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CP0: Compare 0 Interrupt Enable
0: No effect.
1: Enables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Enable
0: No effect.
1: Enables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0: No effect.
1: Enables the Tx Sync Interrupt.
• RXSYN: Rx Sync Interrupt Enable
0: No effect.
1: Enables the Rx Sync Interrupt.
370
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
31.8.15 SSC Interrupt Disable Register
Name: SSC_IDR
Access Type: Write-only
• TXRDY: Transmit Ready Interrupt Disable
0: No effect.
1: Disables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Disable
0: No effect.
1: Disables the Transmit Empty Interrupt.
• ENDTX: End of Transmission Interrupt Disable
0: No effect.
1: Disables the End of Transmission Interrupt.
• TXBUFE: Transmit Buffer Empty Interrupt Disable
0: No effect.
1: Disables the Transmit Buffer Empty Interrupt.
• RXRDY: Receiv e Re ady Interru pt Dis able
0: No effect.
1: Disables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Disable
0: No effect.
1: Disables the Receive Overrun Interrupt.
• ENDRX: End of Reception Interrupt Disable
0: No effect.
1: Disables the End of Reception Interrupt.
• RXBUFF: Receive Buffer Full Interrupt Disable
0: No effect.
1: Disables the Receive Buffer Full Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYNTXSYN CP1 CP0
76543210
RXBUFF ENDRX OVRUN RXRDY TXBUFE ENDTX TXEMPTY TXRDY
371
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CP0: Compare 0 Interrupt Disable
0: No effect.
1: Disables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Disable
0: No effect.
1: Disables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0: No effect.
1: Disables the Tx Sync Interrupt.
• RXSYN: Rx Sync Interrupt Enable
0: No effect.
1: Disables the Rx Sync Interrupt.
372
SAM7X Series [DATASHEET]
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31.8.16 SSC Interrupt Mask Register
Name: SSC_IMR
Access Type: Read-only
• TXRDY: Transmit Ready Interrupt Mask
0: The Transmit Ready Interrupt is disabled.
1: The Transmit Ready Interrupt is enabled.
• TXEMPTY: Transmit Empty Interrupt Mask
0: The Transmit Empty Interrupt is disabled.
1: The Transmit Empty Interrupt is enabled.
• ENDTX: End of Transmission Interrupt Mask
0: The End of Transmission Interrupt is disabled.
1: The End of Transmission Interrupt is enabled.
• TXBUFE: Transmit Buffer Empty Interrupt Mask
0: The Transmit Buffer Empty Interrupt is disabled.
1: The Transmit Buffer Empty Interrupt is enabled.
• RXRDY: Receiv e Re ady Interru pt Ma s k
0: The Receive Ready Interrupt is disabled.
1: The Receive Ready Interrupt is enabled.
• OVRUN: Receive Overrun Interrupt Mask
0: The Receive Overrun Interrupt is disabled.
1: The Receive Overrun Interrupt is enabled.
• ENDRX: End of Reception Interrupt Mask
0: The End of Reception Interrupt is disabled.
1: The End of Reception Interrupt is enabled.
• RXBUFF: Receive Buffer Full Interrupt Mask
0: The Receive Buffer Full Interrupt is disabled.
1: The Receive Buffer Full Interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––RXSYNTXSYN CP1 CP0
76543210
RXBUFF ENDRX OVRUN RXRDY TXBUFE ENDTX TXEMPTY TXRDY
373
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CP0: Compare 0 Interrupt Mask
0: The Compare 0 Interrupt is disabled.
1: The Compare 0 Interrupt is enabled.
• CP1: Compare 1 Interrupt Mask
0: The Compare 1 Interrupt is disabled.
1: The Compare 1 Interrupt is enabled.
• TXSYN: Tx Sync Interrupt Mask
0: The Tx Sync Interrupt is disabled.
1: The Tx Sync Interrupt is enabled.
• RXSYN: Rx Sync Interrupt Mask
0: The Rx Sync Interrupt is disabled.
1: The Rx Sync Interrupt is enabled.
374
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32. Timer Counter (TC)
32.1 Overview
The Timer Counter (TC) includes three identical 16-bit Timer Counter channels.
Each channel can be independently programmed to perform a wide range of functions including frequency
measurement, event counting, interval measurement, pulse generation, delay timing and pulse width modulation.
Each channel has three external clock inputs, five internal clock inputs and two multi-purpose input/output signals which
can be configured by the user. Each channel drives an internal interrupt signal which can be programmed to generate
processor interrupts.
The Timer Counter block has two global registers which act upon all three TC channels.
The Block Control Register allows the three channels to be started simultaneously with the same instruction.
The Block Mode Register defines the external clock inputs for each channel, allowing them to be chained.
Table 32-1 gives the assignment of the device Timer Counter clock inputs common to Timer Counter 0 to 2
Table 32-1. Timer Counter Clock Assignment
Name Definition
TIMER_CLOCK1 MCK/2
TIMER_CLOCK2 MCK/8
TIMER_CLOCK3 MCK/32
TIMER_CLOCK4 MCK/128
TIMER_CLOCK5 MCK/1024
375
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6120K–ATARM–11-Feb-14
32.2 Block Diagram
Figure 32-1. Timer Counter Bloc k Diag ra m
Timer/Counter
Channel 0
Timer/Counter
Channel 1
Timer/Counter
Channel 2
SYNC
Parallel I/O
Controller
TC1XC1S
TC0XC0S
TC2XC2S
INT0
INT1
INT2
TIOA0
TIOA1
TIOA2
TIOB0
TIOB1
TIOB2
XC0
XC1
XC2
XC0
XC1
XC2
XC0
XC1
XC2
TCLK0
TCLK1
TCLK2
TCLK0
TCLK1
TCLK2
TCLK0
TCLK1
TCLK2
TIOA1
TIOA2
TIOA0
TIOA2
TIOA0
TIOA1
Advanced
Interrupt
Controller
TCLK0
TCLK1
TCLK2
TIOA0
TIOB0
TIOA1
TIOB1
TIOA2
TIOB2
Timer Counter
TIOA
TIOB
TIOA
TIOB
TIOA
TIOB
SYNC
SYNC
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
TIMER_CLOCK1
Table 32-2. Signal Name Description
Block/Channel Signal Name Description
Channel Signal
XC0, XC1, XC2 External Clock Inputs
TIOA Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Output
TIOB Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Input/Output
INT Interrupt Signal Output
SYNC Synchronization Input Signal
376
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6120K–ATARM–11-Feb-14
32.3 Pin Name List
32.4 Product Dependencies
32.4.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer must
first program the PIO controllers to assign the TC pins to their peripheral functions.
32.4.2 Power Management
The TC is clocked through the Power Management Controller (PMC), thus the programmer must first configure the PMC
to enable the Timer Counter clock.
32.4.3 Interrupt
The TC has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling the TC interrupt requires
programming the AIC before configuring the TC.
Table 32-3. TC pin list
Pin Name Description Type
TCLK0-TCLK2 External Clock Input Input
TIOA0-TIOA2 I/O Line A I/O
TIOB0-TIOB2 I/O Line B I/O
377
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32.5 Functional Description
32.5.1 TC Description
The three channels of the Timer Counter are independent and identical in operation. The registers for channel
programming are listed in Table 32-4 on page 389.
32.5.2 16-bit Counter
Each channel is organized around a 16-bit counter. The value of the counter is incremented at each positive edge of the
selected clock. When the counter has reached the value 0xFFFF and passes to 0x0000, an overflow occurs and the
COVFS bit in TC_SR (Status Register) is set.
The current value of the counter is accessible in real time by reading the Counter Value Register, TC_CV. The counter
can be reset by a trigger. In this case, the counter value passes to 0x0000 on the next valid edge of the selected clock.
32.5.3 Clock Selection
At block level, input clock signals of each channel can either be connected to the external inputs TCLK0, TCLK1 or
TCLK2, or be connected to the internal I/O signals TIOA0, TIOA1 or TIOA2 for chaining by programming the TC_BMR
(Block Mode). See Figure 32-2 on page 378.
Each channel can independently select an internal or external clock source for its counter:
Internal clock signals: TIMER_CLOCK1, TIMER_CLOCK2, TIMER_CLOCK3, TIMER_CLOCK4, TIMER_CLOCK5
External clock signals: XC0, XC1 or XC2
This selection is made by the TCCLKS bits in the TC Channel Mode Register.
The selected clock can be inverted with the CLKI bit in TC_CMR. This allows counting on the opposite edges of the
clock.
The burst function allows the clock to be validated when an external signal is high. The BURST parameter in the Mode
Register defines this signal (none, XC0, XC1, XC2). See Figure 32-3 on page 378
Note: In all cases, if an external clock is used, the duration of each of its levels must be longer than the master clock
period. The external clock frequency must be at least 2.5 times lower than the master clock
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SAM7X Series [DATASHEET]
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Figure 32-2. Clock Chaining Selection
Figure 32-3. Clock Selection
Timer/Counter
Channel 0
SYNC
TC0XC0S
TIOA0
TIOB0
XC0
XC1 = TCLK1
XC2 = TCLK2
TCLK0 TIOA1
TIOA2
Timer/Counter
Channel 1
SYNC
TC1XC1S
TIOA1
TIOB1
XC0 = TCLK2
XC1
XC2 = TCLK2
TCLK1 TIOA0
TIOA2
Timer/Counter
Channel 2
SYNC
TC2XC2S
TIOA2
TIOB2
XC0 = TCLK0
XC1 = TCLK1
XC2
TCLK2 TIOA0
TIOA1
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
TCCLKS
CLKI
BURST
1
Selected
Clock
379
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.5.4 Clock Control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled and started/stopped. See
Figure 32-4.
The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS commands in the Control
Register. In Capture Mode it can be disabled by an RB load event if LDBDIS is set to 1 in TC_CMR. In Waveform
Mode, it can be disabled by an RC Compare event if CPCDIS is set to 1 in TC_CMR. When disabled, the start or the
stop actions have no effect: only a CLKEN command in the Control Register can re-enable the clock. When the clock
is enabled, the CLKSTA bit is set in the Status Register.
The clock can also be started or stopped: a trigger (software, synchro, external or compare) always starts the clock.
The clock can be stopped by an RB load event in Capture Mode (LDBSTOP = 1 in TC_CMR) or a RC compare event
in Waveform Mode (CPCSTOP = 1 in TC_CMR). The start and the stop commands have effect only if the clock is
enabled.
Figure 32-4. Clock Co ntrol
32.5.5 TC Operating Modes
Each channel can independently operate in two different modes:
Capture Mode provides measurement on signals.
Waveform Mode provides wave generation.
The TC Operating Mode is programmed with the WAVE bit in the TC Channel Mode Register.
In Capture Mode, TIOA and TIOB are configured as inputs.
In Waveform Mode, TIOA is always configured to be an output and TIOB is an output if it is not selected to be the
external trigger.
32.5.6 Trigger
A trigger resets the counter and starts the counter clock. Three types of triggers are common to both modes, and a fourth
external trigger is available to each mode.
The following triggers are common to both modes:
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
Stop
Event Disable
Event
Counter
Clock
Selected
Clock Trigger
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SAM7X Series [DATASHEET]
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Software Trigger: Each channel has a software trigger, available by setting SWTRG in TC_CCR.
SYNC: Each channel has a synchronization signal SYNC. When asserted, this signal has the same effect as a
software trigger. The SYNC signals of all channels are asserted simultaneously by writing TC_BCR (Block Control)
with SYNC set.
Compare RC Trigger: RC is implemented in each channel and can provide a trigger when the counter value matches
the RC value if CPCTRG is set in TC_CMR.
The channel can also be configured to have an external trigger. In Capture Mode, the external trigger signal can be
selected between TIOA and TIOB. In Waveform Mode, an external event can be programmed on one of the following
signals: TIOB, XC0, XC1 or XC2. This external event can then be programmed to perform a trigger by setting ENETRG
in TC_CMR.
If an external trigger is used, the duration of the pulses must be longer than the master clock period in order to be
detected.
Regardless of the trigger used, it will be taken into account at the following active edge of the selected clock. This means
that the counter value can be read differently from zero just after a trigger, especially when a low frequency signal is
selected as the clock.
32.5.7 Capture Operating Mode
This mode is entered by clearing the WAVE parameter in TC_CMR (Channel Mode Register).
Capture Mode allows the TC channel to perform measurements such as pulse timing, frequency, period, duty cycle and
phase on TIOA and TIOB signals which are considered as inputs.
Figure 32-5 shows the configuration of the TC channel when programmed in Capture Mode.
32.5.8 Capture Registers A and B
Registers A and B (RA and RB) are used as capture registers. This means that they can be loaded with the counter value
when a programmable event occurs on the signal TIOA.
The LDRA parameter in TC_CMR defines the TIOA edge for the loading of register A, and the LDRB parameter defines
the TIOA edge for the loading of Register B.
RA is loaded only if it has not been loaded since the last trigger or if RB has been loaded since the last loading of RA.
RB is loaded only if RA has been loaded since the last trigger or the last loading of RB.
Loading RA or RB before the read of the last value loaded sets the Overrun Error Flag (LOVRS) in TC_SR (Status
Register). In this case, the old value is overwritten.
32.5.9 Trigger Conditions
In addition to the SYNC signal, the software trigger and the RC compare trigger, an external trigger can be defined.
The ABETRG bit in TC_CMR selects TIOA or TIOB input signal as a n external trigger. The ETRGEDG parameter defines
the edge (rising, falling or both) detected to generate an external trigger. If ETRGEDG = 0 (none), the external trigger is
disabled.
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 32-5. Capture Mode
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
TCCLKS
CLKI
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
BURST
TIOB
Register C
Capture
Register A Capture
Register B Compare RC =
16-bit Counter
ABETRG
SWTRG
ETRGEDG CPCTRG
TC1_IMR
Trig
LDRBS
LDRAS
ETRGS
TC1_SR
LOVRS
COVFS
SYNC
1
MTIOB
TIOA
MTIOA
LDRA
LDBSTOP
If RA is not loaded
or RB is Loaded If RA is Loaded
LDBDIS
CPCS
INT
Edge
Detector
Edge
Detector
LDRB
Edge
Detector
CLK OVF
RESET
Timer/Counter Channel
382
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.5.10 Waveform Operating Mode
Waveform operating mode is entered by setting the WAVE parameter in TC_CMR (Channel Mode Register).
In Waveform Operating Mode the TC channel generates 1 or 2 PWM signals with the same frequency and independently
programmable duty cycles, or generates different types of one-shot or repetitive pulses.
In this mode, TIOA is configured as an output and TIOB is defined as an output if it is not used as an external event
(EEVT parameter in TC_CMR).
Figure 32-6 shows the configuration of the TC channel when programmed in Waveform Operating Mode.
32.5.11 Waveform Selection
Depending on the WAVSEL parameter in TC_CMR (Channel Mode Register), the behavior of TC_CV varies.
With any selection, RA, RB and RC can all be used as compare registers.
RA Compare is used to control the TIOA output, RB Compare is used to control the TIOB output (if correctly configured)
and RC Compare is used to control TIOA and/or TIOB outputs.
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SAM7X Series [DATASHEET]
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Figure 32-6. Waveform Mode
TCCLKS
CLKI
QS
R
S
R
Q
CLKSTA CLKEN CLKDIS
CPCDIS
BURST
TIOB
Register A Register B Register C
Compare RA = Compare RB = Compare RC =
CPCSTOP
16-bit Counter
EEVT
EEVTEDG
SYNC
SWTRG
ENETRG
WAVSEL
TC1_IMR
Trig
ACPC
ACPA
AEEVT
ASWTRG
BCPC
BCPB
BEEVT
BSWTRG
TIOA
MTIOA
TIOB
MTIOB
CPAS
COVFS
ETRGS
TC1_SR
CPCS
CPBS
CLK OVF
RESET
Output Controller
Output Controller
INT
1
Edge
Detector
Timer/Counter Channel
TIMER_CLOCK1
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
WAVSEL
384
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6120K–ATARM–11-Feb-14
32.5.11.1 WAVSEL = 00
When WAVSEL = 00, the value of TC_CV is incremented from 0 to 0xFFFF. Once 0xFFFF h as been reached, the value
of TC_CV is reset. Incrementation of TC_CV starts again and the cycle continues. See Figure 32-7.
An external event trigger or a software trigger can reset the value of TC_CV. It is important to note that the trigger may
occur at any time. See Figure 32-8.
RC Compare cannot be programmed to generate a trigger in this configuration. At the same time, RC Compare can stop
the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock (CPCDIS = 1 in TC_CMR).
Figure 32-7. WAVSEL= 00 without trigger
Figure 32-8. WAVSEL= 00 with trigger
Time
Counter V alue
RC
RB
RA
TIOB
TIOA
Counter cleared by compare match with 0xFFFF
0xFFFF
Waveform Examples
Time
Counter V alue
RC
RB
RA
TIOB
TIOA
Counter cleared by compare match with 0xFFFF
0xFFFF
Waveform Examples
Counter cleared by trigger
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32.5.11.2 WAVSEL = 10
When WAVSEL = 10, the value of TC_CV is incremented from 0 to the value of RC, then automatically reset on a RC
Compare. Once the value of TC_CV has been reset, it is then incremented and so on. See Figure 32-9.
It is important to note that TC_CV can be reset at any time by an external event or a software trigger if both are
programmed correctly. See Figure 32-10.
In addition, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock
(CPCDIS = 1 in TC_CMR).
Figure 32-9. WAVSEL = 10 Without Trigger
Figure 32-10. WAVSEL = 10 With Trigger
Time
Counter V alue
R
C
R
B
R
A
TIOB
TIOA
Counter cleared by compare match with RC
0xFFFF
Waveform Examples
Time
Counter V alue
R
C
R
B
R
A
TIOB
TIOA
Counter cleared by compare match with RC
0xFFFF
Waveform Examples
Counter cleared by trigger
386
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.5.11.3 WAVSEL = 01
When WAVSEL = 01, the value of TC_CV is incremented from 0 to 0xFFFF. Once 0xFFFF is reached, the value of
TC_CV is decremented to 0, then re-incremented to 0xFFFF and so on. See Figure 32-11.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV
is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV then increments.
See Figure 32-12.
RC Compare cannot be programmed to generate a trigger in this configuration.
At the same time, RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS =
1).
Figure 32-11. WAVSEL = 01 Without Trigger
Figure 32-12. WAVSEL = 01 With Trigger
Time
Counter V alue
RC
RB
RA
TIOB
TIOA
Counter decremented by compare match with 0xFFFF
0xFFFF
Waveform Examples
Time
Counter V alue
TIOB
TIOA
Counter decremented by compare match with 0xFFFF
0xFFFF
Waveform Examples
Counter decremented
by trigger
Counter incremented
by trigger
RC
RB
RA
387
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.5.11.4 WAVSEL = 11
When WAVSEL = 11, the value of TC_CV is incremented from 0 to RC. Once RC is reached, the value of TC_CV is
decremented to 0, then re-incremented to RC and so on. See Figure 32-13.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV
is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV then increments.
See Figure 32-14.
RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1).
Figure 32-13. WAVSEL = 11 Without Trigger
Figure 32-14. WAVSEL = 11 With Trigger
Time
Counter V alue
RC
RB
RA
TIOB
TIOA
Counter decremented by compare match with RC
0xFFFF
Waveform Examples
Time
Counter V alue
TIOB
TIOA
Counter decremented by compare match with RC
0xFFFF
Waveform Examples
Counter decremented
by trigger
Counter incremented
by trigger
RC
RB
RA
388
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.5.12 External Event/Trigger Conditions
An external event can be programmed to be detected on one of the clock sources (XC0, XC1, XC2) or TIOB. The
external event selected can then be used as a trigger.
The EEVT parameter in TC_CMR selects the external trigger. The EEVTEDG parameter defines the trigger edge for
each of the possible external triggers (rising, falling or both). If EEVTEDG is cleared (none), no external event is defined.
If TIOB is defined as an external event signal (EEVT = 0), TIOB is no longer used as an output and the compare register
B is not used to generate waveforms and subsequently no IRQs. In this case the TC channel can only generate a
waveform on TIOA.
When an external event is defined, it can be used as a trigger by setting bit ENETRG in TC_CMR.
As in Capture Mode, the SYNC signal and the software trigger are also available as triggers. RC Compare can also be
used as a trigger depending on the parameter WAVSEL.
32.5.13 Output Controller
The output controller defines the output level changes o n TIOA and TIOB following an event. TIOB control is used only if
TIOB is defined as output (not as an external event).
The following events control TIOA and TIOB: software trigger, external event and RC compare. RA compare controls
TIOA and RB compare controls TIOB. Each of these events can be programmed to set, clear or toggle the output as
defined in the corresponding parameter in TC_CMR.
389
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6 T imer Counter (TC) User Interface
Notes: 1. Channel index ranges from 0 to 2.
2. Read-only if WAVE = 0
Table 32-4. Regist er Mapping(1)
Offset Register Name Access Reset
0x00 + channel * 0x40 + 0x00 Channel Control Register TC_CCR Write-o nly –
0x00 + channel * 0x40 + 0x04 Channel Mode Register TC_CMR Read-write 0
0x00 + channel * 0x40 + 0x08 Reserve
0x00 + channel * 0x40 + 0x0C Reserved
0x00 + channel * 0x40 + 0x10 Counter Value TC_CV Read-only 0
0x00 + channel * 0x40 + 0x14 Register A TC_RA Read-write(2) 0
0x00 + channel * 0x40 + 0x18 Register B TC_RB Read-wri te(2) 0
0x00 + channel * 0x40 + 0x1C Register C TC_RC Read-write 0
0x00 + channel * 0x40 + 0x20 Status Register TC_SR Read-only 0
0x00 + channel * 0x40 + 0x24 Interrupt Enable Register TC_IER Write-only –
0x00 + channel * 0x40 + 0x28 Interrupt Disable Registe r TC_IDR Write-only –
0x00 + channel * 0x40 + 0x2C Interrupt Mask Register TC_IMR Read-only 0
0xC0 Block Control Register TC_BCR Write-only –
0xC4 Block Mode Register TC_BMR Read-write 0
0xFC Reserved – – –
390
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.1 TC Block Control Register
Register Name: TC_BCR
Access Type: Write-only
• SYNC: Synchro Command
0 = No effect.
1 = Asserts the SYNC signal which generates a software trigger simultaneously for each of the channels.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––––SYNC
391
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.2 TC Block Mode Register
Register Name: TC_BMR
Access Type: Read-write
• TC0XC0S: External Clo ck Signal 0 Selection
• TC1XC1S: External Clo ck Signal 1 Selection
• TC2XC2S: External Clo ck Signal 2 Selection
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– – TC2XC2S TC1XC1S TC0XC0S
TC0XC0S Signal Connected to XC0
00TCLK0
0 1 none
10TIOA1
11TIOA2
TC1XC1S Signal Connected to XC1
00TCLK1
0 1 none
10TIOA0
11TIOA2
TC2XC2S Signal Connected to XC2
00TCLK2
0 1 none
10TIOA0
11TIOA1
392
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.3 TC Channel Control Register
Register Name: TC_CCR [x=0..2]
Access Type: Write-only
• CLKEN: Counter Clock Enable Command
0 = No effect.
1 = Enables the clock if CLKDIS is not 1.
• CLKDIS: Counter Clock Disable Command
0 = No effect.
1 = Disables the clock.
• SWTRG: Software Trigger Command
0 = No effect.
1 = A software trigger is performed: the counter is reset and the clock is started.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––SWTRGCLKDISCLKEN
393
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.4 TC Channel Mode Register: Capture Mode
Register Name: TC_CMRx [x=0..2] (WAVE = 0)
Access Type: Read-write
• TCCLKS: Clock Selection
• CLKI: Clock Invert
0 = Counter is incremented on rising edge of the clock.
1 = Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
• LDBSTOP: Counter Clock Stopped with RB Loading
0 = Counter clock is not stopped when RB loading occurs.
1 = Counter clock is stopped when RB loading occurs.
• LDBDIS: Counter Clock Disable with RB Loading
0 = Counter clock is not disabled when RB loading occurs.
1 = Counter clock is disabled when RB loading occurs.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – – – LDRB LDRA
15 14 13 12 11 10 9 8
WAVE CPCTRG – – – ABETRG ETRGEDG
76543210
LDBDIS LDBSTOP BURST CLKI TCCLKS
TCCLKS Clock Selected
0 0 0 TIMER_CLOCK1
0 0 1 TIMER_CLOCK2
0 1 0 TIMER_CLOCK3
0 1 1 TIMER_CLOCK4
1 0 0 TIMER_CLOCK5
101XC0
110XC1
111XC2
BURST
0 0 The clock is not gated by an external signal.
0 1 XC0 is ANDed with the selected clock.
1 0 XC1 is ANDed with the selected clock.
1 1 XC2 is ANDed with the selected clock.
394
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• ETRGEDG: External Trigger Edge Selection
• ABETRG: TIOA or TIOB External Trigger Selection
0 = TIOB is used as an external trigger.
1 = TIOA is used as an external trigger.
• CPCTRG: RC Compare Trigger Enable
0 = RC Compare has no effect on the counter and its clock.
1 = RC Compare resets the counter and starts the counter clock.
•WAVE
0 = Capture Mode is enabled.
1 = Capture Mode is disabled (Waveform Mode is enabled).
• LDRA: RA Loading Selection
• LDRB: RB Loading Selection
ETRGEDG Edge
0 0 none
0 1 rising edge
1 0 falling edge
1 1 each edge
LDRA Edge
0 0 none
0 1 risi ng edge of TIOA
1 0 falling edge of TIOA
1 1 each edge of TIOA
LDRB Edge
0 0 none
0 1 rising edge of TIOA
1 0 fallin g edge of TIOA
1 1 each edge of TIOA
395
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.5 TC Channel Mode Register: Waveform Mode
Register Name: TC_CMRx [x=0..2] (WAVE = 1)
Access Type: Read-write
• TCCLKS: Clock Selection
• CLKI: Clock Invert
0 = Counter is incremented on rising edge of the clock.
1 = Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
• CPCSTOP: Counter Clock Stopped with RC Compare
0 = Counter clock is not stopped when counter reaches RC.
1 = Counter clock is stopped when counter reaches RC.
• CPCDIS: Counter Clock Disable with RC Compare
0 = Counter clock is not disabled when counter reaches RC.
1 = Counter clock is disabled when counter reaches RC.
31 30 29 28 27 26 25 24
BSWTRG BEEVT BCPC BCPB
23 22 21 20 19 18 17 16
ASWTRG AEEVT ACPC ACPA
15 14 13 12 11 10 9 8
WAVE WAVSEL ENETRG EEVT EEVTEDG
76543210
CPCDIS CPCSTOP BURST CLKI TCCLKS
TCCLKS Clock Selected
0 0 0 TIMER_CLOCK1
0 0 1 TIMER_CLOCK2
0 1 0 TIMER_CLOCK3
0 1 1 TIMER_CLOCK4
1 0 0 TIMER_CLOCK5
101XC0
110XC1
111XC2
BURST
0 0 The clock is not gated by an external signal.
0 1 XC0 is ANDed with the selected clock.
1 0 XC1 is ANDed with the selected clock.
1 1 XC2 is ANDed with the selected clock.
396
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• EEVTEDG: External Event Edge Selection
• EEVT: External Event Selection
Note: 1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms and
subsequently no IRQs.
• ENETRG: External Event Trigger Enable
0 = The external event has no effect on the counter and its clock. In this case, the selected external event only controls the TIOA
output.
1 = The external event resets the counter and starts the counter clock.
• WAVSEL: Waveform Selection
•WAVE
0 = Waveform Mode is disabled (Capture Mode is enabled).
1 = Waveform Mode is enabled.
• ACPA: RA Compare Effect on TIOA
EEVTEDG Edge
0 0 none
0 1 rising edge
1 0 falling edge
1 1 each edge
EEVT Signal selected as external event TIOB Direction
0 0 TIOB input (1)
0 1 XC0 output
1 0 XC1 output
1 1 XC2 output
WAVSEL Effect
0 0 UP mode without automatic trigger on RC Compare
1 0 UP mode with automatic trigger on RC Compare
0 1 UPDOWN mode without automatic trigger on RC Compare
1 1 UPDOWN mode with automatic trigger on RC Compare
ACPA Effect
0 0 none
0 1 set
1 0 clear
1 1 toggle
397
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• ACPC: RC Compare Effect on TIOA
• AEEVT: External Event Effect on TIOA
• ASWTRG: Software Trigger Effect on TIOA
• BCPB: RB Compare Effect on TIOB
• BCPC: RC Compare Effect on TIOB
ACPC Effect
0 0 none
0 1 set
1 0 clear
1 1 toggle
AEEVT Effect
0 0 none
0 1 set
1 0 clear
11toggle
ASWTRG Effect
0 0 none
0 1 set
1 0 clear
1 1 toggle
BCPB Effect
0 0 none
0 1 set
1 0 clear
11toggle
BCPC Effect
0 0 none
0 1 set
1 0 clear
1 1 toggle
398
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• BEEVT: External Event Effect on TIOB
• BSWTRG: Software Trigger Effect on TIOB
BEEVT Effect
0 0 none
0 1 set
1 0 clear
1 1 toggle
BSWTRG Effect
0 0 none
01set
1 0 clear
11toggle
399
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.6 TC Counter Value Register
Register Name: TC_CVx [x=0..2]
Access Type: Read-only
• CV: Counter Value
CV contains the counter value in real time.
32.6.7 TC Register A
Register Name: TC_RAx [x=0..2]
Access Type: Read-only if WAVE = 0, Read-write if WAVE = 1
• RA: Register A
RA contains the Register A value in real time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
CV
76543210
CV
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RA
76543210
RA
400
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.8 TC Register B
Register Name: TC_RB [x=0..2]
Access Type: Read-only if WAVE = 0, Read-write if WAVE = 1
• RB: Register B
RB contains the Register B value in real time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RB
76543210
RB
401
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.9 TC Register C
Register Name: TC_RCx [x=0..2]
Access Type: Read-write
• RC: Register C
RC contains the Register C value in real time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RC
76543210
RC
402
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.10 TC St atus Register
Register Name: TC_SRx [x=0..2]
Access Type: Read-only
• COVFS: Counter Overflow Status
0 = No counter overflow has occurred since the last read of the Status Register.
1 = A counter overflow has occurred since the last read of the Status Register.
• LOVRS: Load Overrun Status
0 = Load overrun has not occurred since the last read of the Status Register or WAVE = 1.
1 = RA or RB have been loaded at least twice without any read of the corresponding register since the last read of the Status Reg-
ister, if WAVE = 0.
• CPAS: RA Compare Status
0 = RA Compare has not occurred since the last read of the Status Register or WAVE = 0.
1 = RA Compare has occurred since the last read of the Status Register, if WAVE = 1.
• CPBS: RB Compare Status
0 = RB Compare has not occurred since the last read of the Status Register or WAVE = 0.
1 = RB Compare has occurred since the last read of the Status Register, if WAVE = 1.
• CPCS: RC Compare Status
0 = RC Compare has not occurred since the last read of the Status Register.
1 = RC Compare has occurred since the last read of the Status Register.
• LDRAS: RA Loading Stat us
0 = RA Load has not occurred since the last read of the Status Register or WAVE = 1.
1 = RA Load has occurred since the last read of the Status Register, if WAVE = 0.
• LDRBS: RB Loading Stat us
0 = RB Load has not occurred since the last read of the Status Register or WAVE = 1.
1 = RB Load has occurred since the last read of the Status Register, if WAVE = 0.
• ETRGS: External Trigger Status
0 = External trigger has not occurred since the last read of the Status Register.
1 = External trigger has occurred since the last read of the Status Register.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
–––––MTIOBMTIOACLKSTA
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
403
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CLKSTA: Clock Enabling Statu s
0 = Clock is disabled.
1 = Clock is enabled.
• MTIOA: TIOA Mirror
0 = TIOA is low. If WAVE = 0, this means that TIOA pin is low. If WAVE = 1, this means that TIOA is driven low.
1 = TIOA is high. If WAVE = 0, this means that TIOA pin is high. If WAVE = 1, this means that TIOA is driven high.
• MTIOB: TIOB Mirror
0 = TIOB is low. If WAVE = 0, this means that TIOB pin is low. If WAVE = 1, this means that TIOB is driven low.
1 = TIOB is high. If WAVE = 0, this means that TIOB pin is high. If WAVE = 1, this means that TIOB is driven high.
404
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.11 TC Interrupt Enable Register
Register Name: TC_IERx [x=0..2]
Access Type: Write-only
• COVFS: Counter Overflow
0 = No effect.
1 = Enables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0 = No effect.
1 = Enables the Load Overrun Interrupt.
• CPAS: RA Compare
0 = No effect.
1 = Enables the RA Compare Interrupt.
• CPBS: RB Compare
0 = No effect.
1 = Enables the RB Compare Interrupt.
• CPCS: RC Compare
0 = No effect.
1 = Enables the RC Compare Interrupt.
• LDRAS: RA Loading
0 = No effect.
1 = Enables the RA Load Interrupt.
• LDRBS: RB Loading
0 = No effect.
1 = Enables the RB Load Interrupt.
• ETRGS: External Trigger
0 = No effect.
1 = Enables the External Trigger Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
405
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.12 TC Interrupt Disable Register
Register Name: TC_IDR [x=0..2]
Access Type: Write-only
• COVFS: Counter Overflow
0 = No effect.
1 = Disables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0 = No effect.
1 = Disables the Load Overrun Interrupt (if WAVE = 0).
• CPAS: RA Compare
0 = No effect.
1 = Disables the RA Compare Interrupt (if WAVE = 1).
• CPBS: RB Compare
0 = No effect.
1 = Disables the RB Compare Interrupt (if WAVE = 1).
• CPCS: RC Compare
0 = No effect.
1 = Disables the RC Compare Interrupt.
• LDRAS: RA Loading
0 = No effect.
1 = Disables the RA Load Interrupt (if WAVE = 0).
• LDRBS: RB Loading
0 = No effect.
1 = Disables the RB Load Interrupt (if WAVE = 0).
• ETRGS: External Trigger
0 = No effect.
1 = Disables the External Trigger Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
406
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
32.6.13 TC Interrupt Mask Register
Register Name: TC_IMRx [x=0..2]
Access Type: Read-only
• COVFS: Counter Overflow
0 = The Counter Overflow Interrupt is disabled.
1 = The Counter Overflow Interrupt is enabled.
• LOVRS: Load Overrun
0 = The Load Overrun Interrupt is disabled.
1 = The Load Overrun Interrupt is enabled.
• CPAS: RA Compare
0 = The RA Compare Interrupt is disabled.
1 = The RA Compare Interrupt is enabled.
• CPBS: RB Compare
0 = The RB Compare Interrupt is disabled.
1 = The RB Compare Interrupt is enabled.
• CPCS: RC Compare
0 = The RC Compare Interrupt is disabled.
1 = The RC Compare Interrupt is enabled.
• LDRAS: RA Loading
0 = The Load RA Interrupt is disabled.
1 = The Load RA Interrupt is enabled.
• LDRBS: RB Loading
0 = The Load RB Interrupt is disabled.
1 = The Load RB Interrupt is enabled.
• ETRGS: External Trigger
0 = The External Trigger Interrupt is disabled.
1 = The External Trigger Interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS
407
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33. Pulse Width Modulation Controller (PWM)
33.1 Overview
The PWM macrocell controls several channels independently. Each channel controls one square output waveform.
Characteristics of the output waveform such as period, duty-cycle and polarity are configurable through the user
interface. Each channel selects and uses one of the clocks provided by the clock generator. The clock generator
provides several clocks resulting from the division of the PWM macrocell master clock.
All PWM macrocell accesses are made through APB mapped registers.
Channels can be synchronized, to generate non overlapped waveforms. All channels integrate a double buffering system
in order to prevent an unexpected output waveform while modifying the period or the duty-cycle.
33.2 Block Diagram
Figure 33-1. Pulse Width Modulation Controller Block Diagram
PWM
Controller
APB
PWMx
PWMx
PWMx
Channel
Update
Duty Cycle
Counter
PWM0
Channel
PIO
AICPMC MCK Clock Generator APB Interface Interrupt Generator
Clock
Selector
Period
Comparator
Update
Duty Cycle
Counter
Clock
Selector
Period
Comparator
PWM0
PWM0
408
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.3 I/O Lines Description
Each channel outputs one waveform on one external I/O line.
33.4 Product Dependencies
33.4.1 I/O Lines
The pins used for interfacing the PWM may be multiplexed with PIO lines. The programmer must first program the PIO
controller to assign the desired PWM pins to their peripheral function. If I/O lines of the PWM are not used by the
application, they can be used for other purposes by the PIO controller.
All of the PWM outputs may or may not be enabled. If an application requires only four channels, then only four PIO lines
will be assigned to PWM outputs.
33.4.2 Power Management
The PWM is not continuously clocked. The programmer must first enable the PWM clock in the Power Management
Controller (PMC) before using the PWM. However, if the application does not require PWM operations, the PWM clock
can be stopped when not needed and be restarted later. In this case, the PWM will resume its operations where it left off.
Configuring the PWM does not require the PWM clock to be enabled.
33.4.3 Interrupt Sources
The PWM interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the PWM
interrupt requires the AIC to be programmed first. Note that it is not recommended to use the PWM interrupt line in edge
sensitive mode.
33.5 Functional Description
The PWM macrocell is primarily composed of a clock generator module and 4 channels.
Clocked by the system clock, MCK, the clock generator module provides 13 clocks.
Each channel can independently choose one of the clock generator outputs.
Each channel generates an output waveform with attributes that can be defined independently for each
channel through the user interface registers.
Table 33-1. I/O Line Description
Name Description Type
PWMx PWM Waveform Output for channel x Output
409
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.5.1 PWM Clock Generator
Figure 33-2. Functional View of the Clock Generator Block Diagram
Caution: Before using the PWM macrocell, the programmer must first enable the PWM clock in the Power Managemen t
Controller (PMC).
The PWM macrocell master clock, MCK, is divided in the clock generator module to provide different clocks available for
all channels. Each channel can independently select one of the divided clocks.
The clock generator is divided in three blocks:
a modulo n counter which provides 11 clocks: FMCK, FMCK/2, FMCK/4, FMCK/8, FMCK/16, FMCK/32, FMCK/64,
FMCK/128, FMCK/256, FMCK/512, FMCK/1024
two linear dividers (1, 1/2, 1/3, ... 1/255) that provide two separate clocks: clkA and clkB
Each linear divider can independently divide one of the clocks of the modulo n counter. The selection of the clock to be
divided is made according to the PREA (PREB) field of the PWM Mode register (PWM_MR). The resulting clock clkA
(clkB) is the clock selected divided by DIVA (DIVB) field value in the PWM Mode register (PWM_MR).
After a reset of the PWM controller, DIVA (DIVB) and PREA (PREB) in the PWM Mode register are set to 0. This implies
that after reset clkA (clkB) are turned off.
At reset, all clocks provided by the modulo n counter are turned off except clock “clk”. This situation is also true when the
PWM master clock is turned off through the Power Management Controller.
modulo n counter
MCK
MCK/2
MCK/4
MCK/16
MCK/32
MCK/64
MCK/8
Divider A clkA
DIVA
PWM_MR
MCK
MCK/128
MCK/256
MCK/512
MCK/1024
PREA
Divider B clkB
DIVB
PWM_MR
PREB
410
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.5.2 PWM Channel
33.5.2.1 Block Diagram
Figure 33-3. Functional View of the Channel Block Diagra m
Each of the 4 channels is composed of three blocks:
A clock selector which selects one of the clocks provided by the clock generator described in Section 33.5.1 “PWM
Clock Generator” on page 409.
An internal counter clocked by the output of the clock selector. This internal counter is incremented or
decremented according to the channel configuration and comp arators events. The size of the internal counter is 16
bits.
A comparator used to generate events according to the internal counter value. It also computes the PWMx output
waveform according to the configuration.
33.5.2.2 Waveform Properties
The different properties of output waveforms are:
the internal clock selection. The internal channel counter is clocked by one of the clocks provided by the clock
generator described in the previous section. This channel parameter is defined in the CPRE field of the
PWM_CMRx register. This field is reset at 0.
the waveform period. This channel parameter is defined in the CPRD field of the PWM_CPRDx register.
- If the waveform is lef t aligned, th en the output waveform period depends on the counter source clock an d can be
calculated:
By using the Master Clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024), the resulting period formula will be:
By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
or
If the waveform is center aligned then the output waveform period depends on the counter source clock and can
be calculated:
By using the Master Clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula will be:
By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
Comparator PWMx
output waveform
Internal
Counter
Clock
Selector
inputs
from clock
generator
inputs from
APB bus
Channel
XCPRD×()
MCK
-------------------------------
CRPD DIVA×()
MCK
------------------------------------------
CRPD DIVAB×()
MCK
----------------------------------------------
2XCPRD××()
MCK
----------------------------------------
411
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
or
the waveform duty cycle. This channel parameter is defined in the CDTY field of the PWM_CDTYx register.
If the waveform is left aligned then:
If the waveform is center aligned, then:
the waveform polarity. At the beginning of the period, the signal can be at high or low level. This property is
defined in the CPOL field of the PWM_CMRx register. By default the signal starts by a low level.
the waveform alignment. The output waveform can be left or center aligned. Center aligned waveforms can be
used to generate non overlapped waveforms. This property is defined in the CALG field of the PWM_CMRx
register. The default mode is left aligned.
Figure 33-4. Non Overlapped Center Aligned Waveforms
Note: See Figure 33-5 on page 412 for a detailed description of center aligned waveforms.
When center aligned, the internal channel counter increases up to CPRD and.decreases down to 0. This ends the period.
When left aligned, the internal channel counter increases up to CPRD and is reset. This ends the period.
Thus, for the same CPRD value, the period for a center aligned channel is twice the period for a left aligned channel.
Waveforms are fixed at 0 when:
CDTY = CPRD and CPOL = 0
CDTY = 0 and CPOL = 1
Waveforms are fixed at 1 (once the channel is enabled) when:
CDTY = 0 and CPOL = 0
CDTY = CPRD and CPOL = 1
The waveform polarity must be set before enabling the channel. This immediately affects the channel output level.
Changes on channel polarity are not taken into account while the channel is enabled.
2CPRD DIVA××()
MCK
---------------------------------------------------
2CPRD×DIVB×()
MCK
---------------------------------------------------
duty cycle period 1 fchannel_x_clock CDTY×⁄–()
period
----------------------------------------------------------------------------------------------------
=
duty cycle period 2⁄()1 fchannel_x_clock CDTY×⁄–())
period 2⁄()
-------------------------------------------------------------------------------------------------------------------
=
PWM0
PWM1
Period
No overlap
412
SAM7X Series [DATASHEET]
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Figure 33-5. Waveform Properties
33.5.3 PWM Controller Operations
33.5.3.1 Initialization
Before enabling the output channel, this channel must have been configured by the software application:
PWM_MCKx
CHIDx(PWM_SR)
Center Aligned
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
PWM_CCNTx
Output W av ef orm PWMx
CPOL(PWM_CMRx) = 0
Output W av ef orm PWMx
CPOL(PWM_CMRx) = 1
CHIDx(PWM_ISR)
Left Aligned
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
PWM_CCNTx
Output W av ef orm PWMx
CPOL(PWM_CMRx) = 0
Output Waveform PWMx
CPOL(PWM_CMRx) = 1
CHIDx(PWM_ISR)
CALG(PWM_CMRx) = 0
CALG(PWM_CMRx) = 1
Period
Period
CHIDx(PWM_ENA)
CHIDx(PWM_DIS)
413
SAM7X Series [DATASHEET]
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Configuration of the clock generator if DIVA and DIVB are required
Selection of the clock for each channel (CPRE field in the PWM_CMRx register)
Configuration of the waveform alignment for each channel (CALG field in the PWM_CMRx register)
Configuration of the period for each channel (CPRD in the PWM_CPRDx register). Writing in PWM_CPRDx
Register is possible while the channel is disabled. After validation of the channel, the user must use PWM_CUPDx
Register to update PWM_CPRDx as explained below.
Configuration of the duty cycle for each channel (CDTY in the PWM_CDTYx register). Writing in PWM_CDTYx
Register is possible while the channel is disabled. After validation of the channel, the user must use PWM_CUPDx
Register to update PWM_CDTYx as explained below.
Configuration of the output waveform polarity for each channel (CPOL in the PWM_CMRx register)
Enable Interrupts (Writing CHIDx in the PWM_IER register)
Enable the PWM channel (Writing CHIDx in the PWM_ENA register)
It is possible to synchronize different channels by enabling them at the same time by means of writing simultaneously
several CHIDx bits in the PWM_ENA register.
In such a situation, all channels may have the same clock selector configuration and the same period specified.
33.5.3.2 Source Clock Selection Criteria
The large number of source clocks can make selection difficult. The relationship between the value in the Period Register
(PWM_CPRDx) and the Duty Cycle Register (PWM_CDTYx) can help the user in choosing. The event number written in
the Period Register gives the PWM accuracy. The Duty Cycle quantum cannot be lower than 1/PWM_CPRDx value. The
higher the value of PWM_CPRDx, the greater the PWM accuracy.
For example, if the user sets 15 (in decimal) in PWM_CPRDx, the user is able to set a value between 1 up to 14 in
PWM_CDTYx Register. The resulting duty cycle quantum cannot be lower than 1/15 of the PWM period.
33.5.3.3 Changing the Duty Cycle or the Period
It is possible to modulate the output waveform duty cycle or period.
To prevent unexpected output waveform, the user must use the update register (PWM_CUPDx) to change waveform
parameters while the channel is still enabled. The user can write a new period value or duty cycle value in the update
register (PWM_CUPDx). This register holds the new value until the end of the current cycle and updates the value for the
next cycle. Depending on the CPD field in the PWM_CMRx register, PWM_CUPDx either updates PWM_CPRDx or
PWM_CDTYx. Note that even if the update register is used, the period must not be smaller than the duty cycle.
Figure 33-6. S yn chronized Period or Duty Cycle Update
PWM_CUPDx Value
PWM_CPRDx PWM_CDTYx
End of Cycle
PWM_CMRx. CPD
User's Writing
10
414
SAM7X Series [DATASHEET]
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To prevent overwriting the PWM_CUPDx by software, the user can use status events in order to synchronize his
software. Two methods are possible. In both, the user must enable the dedicated interrupt in PWM_IER at PWM
Controller level.
The first method (polling method) consists of reading the relevant status bit in PWM_ISR Register according to the
enabled channel(s). See Figure 33-7.
The second method uses an Interrupt Service Routine associated with the PWM channel.
Note: Reading the PWM_ISR register automatically clears CHIDx flags.
Figure 33-7. Polling Method
Note: Polarity and alignment can be modified only when the channel is disabled.
33.5.3.4 Interrupts
Depending on the interrupt mask in the PWM_IMR register, an interrupt is generated at the end of the corresponding
channel period. The interrupt remains active until a read operation in the PWM_ISR register occurs.
A channel interrupt is enabled by setting the corresponding bit in the PWM_IER register. A channel interrupt is disabled
by setting the corresponding bit in the PWM_IDR register.
Writing in PWM_CUPDx
The last write has been taken into account
CHIDx = 1
Writing in CPD field
Update of the Period or Duty Cycle
PWM_ISR Read
Acknowledgement and clear previous register state
YES
415
SAM7X Series [DATASHEET]
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33.6 Pulse Width Modulation Controller (PWM) User Interface
Note: 1. Some registers are indexed with “ch_num” index ranging from 0 to X-1.
Table 33-2. Regist er Mapping
Offset (1) Register Name Access Reset
0x00 PWM Mode Register PWM_MR Read-write 0
0x04 PWM Enable Register PWM_ENA Write-only -
0x08 PWM Disable Register PWM_DIS Write-only -
0x0C PWM Status Register PWM_SR Read-only 0
0x10 PWM Interrupt Enab le Register PWM_IER Write-only -
0x14 PWM Interrupt Disable Register PWM_IDR Write-only -
0x18 PWM Interrupt Mask Register PWM_IMR Read-only 0
0x1C PWM Interrupt Status Register PWM_ISR Read-only 0
0x4C - 0xFC Reserved – – –
0x100 - 0x1FC Reserved
0x200 + ch_num * 0x20 + 0x00 PWM Channel Mode Register PWM_CMR Read-write 0x0
0x200 + ch_num * 0x20 + 0x04 PWM Channel Duty Cycle Register PWM_CDTY Read-w rite 0x0
0x200 + ch_num * 0x20 + 0x08 PWM Channel Period Register PWM_CPRD Read-write 0x0
0x200 + ch_num * 0x20 + 0x0C PWM Channel Counter Register PWM_CCNT Re ad-only 0x0
0x200 + ch_num * 0x20 + 0x10 PWM Channel Update Register PWM_CUPD Write-only -
416
SAM7X Series [DATASHEET]
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33.6.1 PWM Mode Register
Register Name: PWM_MR
Access Type: Read-write
• DIVA, DIVB: CLKA, CLKB Divide Factor
• PREA, PREB
31 30 29 28 27 26 25 24
–––– PREB
23 22 21 20 19 18 17 16
DIVB
15 14 13 12 11 10 9 8
–––– PREA
76543210
DIVA
DIVA, DIVB CLKA, CLKB
0 CLKA, CLKB clock is turned off
1 CLKA, CLKB clock is clock selected by PREA, PREB
2-255 CLKA, CLKB clock is clock selected by PREA, PREB divided by DIVA, DIVB factor.
PREA, PREB Divider Input Clock
0000MCK.
0001MCK/2
0010MCK/4
0011MCK/8
0100MCK/16
0101MCK/32
0110MCK/64
0111MCK/128
1000MCK/256
1001MCK/512
1010MCK/1024
Other Reserved
417
SAM7X Series [DATASHEET]
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33.6.2 PWM Enable Register
Register Name: PWM_ENA
Access Type: Write-only
• CHIDx: Channel ID
0 = No effect.
1 = Enable PWM output for channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
418
SAM7X Series [DATASHEET]
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33.6.3 PWM Disable Register
Register Name: PWM_DIS
Access Type: Write-only
• CHIDx: Channel ID
0 = No effect.
1 = Disable PWM output for channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
419
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.4 PWM Status Register
Register Name: PWM_SR
Access Type: Read-only
• CHIDx: Channel ID
0 = PWM output for channel x is disabled.
1 = PWM output for channel x is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
420
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.5 PWM Interrupt Enable Register
Register Name: PWM_IER
Access Type: Write-only
• CHIDx: Channel ID.
0 = No effect.
1 = Enable interrupt for PWM channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
421
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.6 PWM Interrupt Disable Register
Register Name: PWM_IDR
Access Type: Write-only
• CHIDx: Channel ID.
0 = No effect.
1 = Disable interrupt for PWM channel x.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
422
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.7 PWM Interrupt Mask Register
Register Name: PWM_IMR
Access Type: Read-only
• CHIDx: Channel ID.
0 = Interrupt for PWM channel x is disabled.
1 = Interrupt for PWM channel x is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
423
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.8 PWM Interrupt Status Register
Register Name: PWM_ISR
Access Type: Read-only
• CHIDx: Channel ID
0 = No new channel period has been achieved since the last read of the PWM_ISR register.
1 = At least one new channel period has been achieved since the last read of the PWM_ISR register.
Note: Reading PWM_ISR automatically clears CHIDx flags.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––CHID3CHID2CHID1CHID0
424
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.9 PWM Channel Mode Register
Register Name: PWM_CMR[0..X-1]
Access Type: Read-write
• CPRE: Channel Pre-scaler
• CALG: Channel Alignment
0 = The period is left aligned.
1 = The period is center aligned.
• CPOL: Channel Polarity
0 = The output waveform starts at a low level.
1 = The output waveform starts at a high level.
• CPD: Channel Update Period
0 = Writing to the PWM_CUPDx will modify the duty cycle at the next period start event.
1 = Writing to the PWM_CUPDx will modify the period at the next period start event.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––CPDCPOLCALG
76543210
–––– CPRE
CPRE Channel Pre-scaler
0000MCK
0001MCK/2
0010MCK/4
0011MCK/8
0100MCK/16
0101MCK/32
0110MCK/64
0111MCK/128
1000MCK/256
1001MCK/512
1010MCK/1024
1011CLKA
1100CLKB
Other Reserved
425
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.10 PWM Channel Duty Cycle Register
Register Name: PWM_CDTY[0..X-1]
Access Type: Read-write
Only the first 16 bits (internal channel counter size) are significant.
• CDTY: Channel Duty Cycle
Defines the waveform duty cycle. This value must be defined between 0 and CPRD (PWM_CPRx).
31 30 29 28 27 26 25 24
CDTY
23 22 21 20 19 18 17 16
CDTY
15 14 13 12 11 10 9 8
CDTY
76543210
CDTY
426
SAM7X Series [DATASHEET]
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33.6.11 PWM Channel Period Register
Register Name: PWM_CPRD[0. X-1]
Access Type: Read-write
Only the first 16 bits (internal channel counter size) are significant.
• CPRD: Channel Period
If the waveform is left-aligned, then the output waveform period depends on the counter source clock and can be calculated:
– By using the Master Clock (M CK) divided by an X give n prescaler v alue (with X being 1, 2, 4, 8, 16, 32, 64, 128,
256, 512, or 1024). The resulting period formula will be:
– By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
or
If the waveform is center-aligned, then the output waveform period depends on the counter source clock and can be calculated:
– By using the Master Clock (M CK) divided by an X give n prescaler v alue (with X being 1, 2, 4, 8, 16, 32, 64, 128,
256, 512, or 1024). The resulting period formula will be:
– By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
or
31 30 29 28 27 26 25 24
CPRD
23 22 21 20 19 18 17 16
CPRD
15 14 13 12 11 10 9 8
CPRD
76543210
CPRD
XCPRD×()
MCK
-------------------------------
CRPD DIVA×()
MCK
------------------------------------------
CRPD DIVAB×()
MCK
----------------------------------------------
2XCPRD××()
MCK
----------------------------------------
2CPRD DIVA××()
MCK
---------------------------------------------------
2CPRD×DIVB×()
MCK
---------------------------------------------------
427
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.12 PWM Channel Counter Register
Register Name: PWM_CCNT[0..X-1]
Access Type: Read-only
• CNT: Channel Counter Register
Internal counter value. This register is reset when:
• the channel is enabled (writing CHIDx in the PWM_ENA register).
• the counter re aches CPRD value defined in the PWM _ CPRDx register if the waveform is left aligned.
31 30 29 28 27 26 25 24
CNT
23 22 21 20 19 18 17 16
CNT
15 14 13 12 11 10 9 8
CNT
76543210
CNT
428
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
33.6.13 PWM Channel Update Register
Register Name: PWM_CUPD[0..X-1]
Access Type: Write-only
This register acts as a double buffer for the period or the duty cycle. This prevents an unexpected waveform when modifying the
waveform period or duty-cycle.
Only the first 16 bits (internal channel counter size) are significant.
31 30 29 28 27 26 25 24
CUPD
23 22 21 20 19 18 17 16
CUPD
15 14 13 12 11 10 9 8
CUPD
76543210
CUPD
CPD (PWM_CMRx Register)
0The duty-cycle (CDTY in the PWM_CDTYx register) is update d with the CUPD value at the
beginning of the next period.
1The period (CPRD in the PWM_CPRDx register) is updated with the CUPD value at the beginning
of the next period.
429
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
34. USB Device Port (UDP)
34.1 Overview
The USB Device Port (UDP) is compliant with the Universal Serial Bus (USB) V2.0 full-speed device specification.
Each endpoint can be configured in one of several USB transfer types. It can be associated with one or two banks of a
dual-port RAM used to store the current data payload. If two banks are used, one DPR bank is read or written by the
processor, while the other is read or written by the USB device peripheral. This feature is mandatory for isochronous
endpoints. Thus the device maintains the maximum bandwidth (1M bytes/s) by working with endpoints with two banks of
DPR.
Note: 1. The Dual-Bank function provides two banks for an endpoint. This feature is used for ping-pong mode.
Suspend and resume are automatically detected by the USB device, which notifies the processor by raising an interrupt.
Depending on the product, an external signal can be used to send a wake up to the USB host controller.
34.2 Block Diagram
Figure 34-1 . Block Diagram
Table 34-1. USB Endpo int Description
Endpoint Number Mnemonic Dual-Bank(1) Max. Endpoint Size Endpoint Type
0 EP0 No 8 Control/Bulk/Interrupt
1 EP1 Yes 64 Bulk/Iso/Interrupt
2 EP2 Yes 64 Bulk/Iso/Interrupt
3 EP3 No 64 Control/Bulk/Interrupt
4 EP4 Yes 256 Bulk/Iso/Interrupt
5 EP5 Yes 256 Bulk/Iso/Interrupt
Atmel Bridge
12 MHz
Suspend/Resume Logic
W
r
a
p
p
e
r
W
r
a
p
p
e
r
U
s
e
r
I
n
t
e
r
f
a
c
e
Serial
Interface
Engine
SIE
MCK
Master Clock
Domain
Dual
Port
RAM
FIFO
UDPCK
Recovered 12 MHz
Domain
udp_int
USB Device
Embedded
USB
Transceiver
DP
DM
external_resume
APB
to
MCU
Bus
txoen
eopn
txd
rxdm
rxd
rxdp
430
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Access to the UDP is via the APB bus interface. Read and write to the data FIFO are done by reading and writing 8-bit
values to APB registers.
The UDP peripheral requires two clocks: one peripheral clock used by the MCK domain and a 48 MHz clock used by the
12 MHz domain.
A USB 2.0 full-speed pad is embedded and controlled by the Serial Interface Engine (SIE).
The signal external_resume is optional. It allows the UDP peripheral to wake up once in system mode. The host is then
notified that the device asks for a resume. This optional feature must be also negotiated with the host during the
enumeration.
34.3 Product Dependencies
For further details on the USB Device hardware implementation, see the specific Product Properties document.
The USB physical transceiver is integrated into the product. The bidirectional differential signals DP and DM are
available from the product boundary.
Two I/O lines may be used by the application:
One to check that VBUS is still available from the host. Self-powered devices may use this entry to be notified that
the host has been powered off. In this case, the board pullup on DP must be disabled in order to prevent feeding
current to the host.
One to control the board pullup on DP. Thus, when the device is ready to communicate with the host, it activates its
DP pullup through this control line.
34.3.1 I/O Lines
DP and DM are not controlled by any PIO controllers. The embedded USB physical transceiver is controlled by the USB
device peripheral.
To reserve an I/O line to check VBUS, the programmer must first program the PIO controller to assign this I/O in input
PIO mode.
To reserve an I/O line to control the board pullup, the programmer must first program the PIO controller to assign this I/O
in output PIO mode.
34.3.2 Power Management
The USB device peripheral requires a 48 MHz clock. This clock must be generated by a PLL with an accuracy of ±
0.25%.
Thus, the USB device receives two clocks from the Power Management Controller (PMC): the master clock, MCK, used
to drive the peripheral user interface, and the UDPCK, used to interface with the bus USB signals (recovered 12 MHz
domain).
WARNING: The UDP peripheral clock in the Power Management Controller (PMC) must be enabled before any
read/write operations to the UDP registers including the UDP_TXCV register.
34.3.3 Interrupt
The USB device interface has an interrupt line connected to the Advanced Interrupt Controller (AIC).
Handling the USB device interrupt requires programming the AIC before configuring the UDP.
431
SAM7X Series [DATASHEET]
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34.4 Typical Connection
Figure 34-2. Board Schematic to Interface USB Device Peripheral
34.4.1 USB Device Transceiver
The USB device transceiver is embedded in the product. A few discrete components are required as follows:
the application detects all device states as defined in chapter 9 of the USB specification;
pullup enable/disable
VBUS monitoring
to reduce power consumption the host is disconnected
for line termination.
Pullup enable/disable is done through a MOSFET controlled by a PIO. The pullup is enabled when the PIO drives a 0.
Thus PIO default state to 1 corresponds to a pullup disable. Once the pullup is enabled, the host will force a device reset
100 ms later. Bus powered devices must connect the pullup within 100 ms.
34.4.2 VBUS Monitoring
VBUS monitoring is required to detect host connection. VBUS monitoring is done using a standard PIO with internal
pullup disabled. When the host is switched off, it should be considered as a disconnect, the pullup must be disabled in
order to prevent powering the host through the pull-up resistor.
When the host is disconnected and the transceiver is enabled, then DDP and DDM are floating. This may lead to over
consumption. A solution is to connect 330 KΩ pulldowns on DP and DM. These pulldowns do not alter DDP and DDM
signal integrity.
A termination serial resistor must be connected to DP and DM. The resistor value is defined in the electrical specification
of the product (REXT).
3V3
R
EXT
DDM
DDP
PIO
PIO 27 K
47 K
330 K
Type B
Connector
12
34
5V Bus Monitoring
Pullup Control
R
EXT
330 K
1.5K
0: Enable
1: Disable
432
SAM7X Series [DATASHEET]
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34.5 Functional Description
34.5.1 USB V2.0 Full-speed Introduction
The USB V2.0 full-speed provides communication services between host and attached USB devices. Each device is
offered with a collection of communication flows (pipes) associated with each endpoint. Software on the host
communicates with a USB device through a set of communication flows.
Figure 34-3. Example of USB V2.0 Full-speed Communication Control
The Control Transfer endpoint EP0 is always used when a USB device is first configured (USB v. 2.0 specifications).
34.5.1.1 USB V2.0 Full-speed Transfer Types
A communication flow is carried over one of four transfer types defined by the USB device.
EP0
USB Host V2.0
Software Client 1 Software Client 2
Data Flow: Bulk Out Transfer
Data Flow: Bulk In Transfer
Data Flow: Control Transfer
Data Flow: Control Transfer
EP1
EP2
USB Device 2.0
Block 1
USB Device 2.0
Block 2
EP5
EP4
EP0
Data Flow: Isochronous In Transfer
Data Flow: Isochronous Out Transfer
USB Device endpoint configuration requires that
in the first instance Control Transfer must be EP0.
Table 34-2. USB Communication Flow
Transfer Direction Bandwidth Supported Endpoint Size Error Detection Retrying
Control Bidirectional Not guaranteed 8, 16, 32, 64 Yes Automatic
Isochronous Unidirectional Guaranteed 256 Yes No
Interrupt Uni directional Not guaranteed ≤ 64 Yes Yes
Bulk Unidirectional Not guaranteed 8, 16, 32, 64 Yes Yes
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SAM7X Series [DATASHEET]
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34.5.1.2 USB Bus Tr ansactions
Each transfer results in one or more transactions over the USB bus. There are three kinds of transactions flowing across
the bus in packets:
1. Setup Tr ansaction
2. Data IN Transaction
3. Data OUT Transaction
34.5.1.3 USB Transfer Event Definitions
As indicated below, transfers are sequential events carried out on the USB bus.
Notes: 1. Control transfer must use endpoints with no ping-pong attributes.
2. Isochronous transfers must use endpoints with ping-pong attributes.
3. Control transfers can be aborted using a stall handshake.
A status transaction is a special type of host-to-device transaction used only in a control transfer. The control transfer
must be performed using endpoints with no ping-pong attributes. According to the control sequence (read or write), the
USB device sends or receives a status transaction.
Table 34-3 . USB Trans fe r Even ts
Control Transfers(1) (3)
Setup transaction > Data IN transactions > Status
OUT transaction
Setup transaction > Data OUT transactions > Status
IN transaction
Setup transaction > Status IN transaction
Interrupt IN T ransfer
(device toward host)
Data IN transaction > Data IN transaction
Interrupt OUT Transfer
(host toward device)
Data OUT transaction > Data OUT transaction
Isochronous IN T ran sfer(2)
(device toward host)
Data IN transaction > Data IN transaction
Isochronous OUT Transfer(2)
(host toward device)
Data OUT transaction > Data OUT transaction
Bulk IN Transfer
(device toward host)
Data IN transaction > Data IN transaction
Bulk OUT Transfer
(host toward device)
Data OUT transaction > Data OUT transaction
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Figure 34-4. Control Read and Write Sequences
Notes: 1. During the Status IN stage, the host waits for a zero length packet (Data IN transaction with no data) from the device using
D ATA1 PID. Ref er to Chapter 8 of the Univ ersal Serial Bus Specification, Rev. 2.0, fo r more information on the prot ocol la y e r.
2. During the Status OUT stage, the host emits a zero length packet to the device (Data OUT transaction with no data).
34.5.2 Handling Transactions with USB V2.0 Device Peripheral
34.5.2.1 Setup Transaction
Setup is a special type of host-to-device transaction used during control transfers. Control transfers must be performed
using endpoints with no ping-pong attributes. A setup transaction needs to be handled as soon as possible by the
firmware. It is used to transmit requests from the host to the device. These requests are then handled by the USB device
and may require more arguments. The arguments are sent to the device by a Data OUT transaction which follows the
setup transaction. These requests may also return data. The data is carried out to the host by the next Data IN
transaction which follows the setup transaction. A status transaction ends the control transfer.
When a setup transfer is received by the USB endpoint:
The USB device automatically acknowledges the setup packet?
RXSETUP is set in the UDP_ CSRx register ?
An endpoint interrupt is generated while the RXSETUP is not cleared. This interrupt is carried out to the
microcontroller if interrupts are enabled for this endpoint.
Thus, firmware must detect the RXSETUP polling the UDP_ CSRx or catching an interrupt, read the setup packet in the
FIFO, then clear the RXSETUP. RXSETUP cannot be cleared before the setup packet has been read in the FIFO.
Otherwise, the USB device would accept the next Data OUT transfer and overwrite the setup packet in the FIFO.
Control Read Setup TX Data OUT TX Data OUT TX
Data Stage
Control Write
Setup Stage
Setup Stage
Setup TX
Setup TX
No Data
Control
Data IN TX Data IN TX
Status Stage
Status Stage
Status IN TX
Status OUT TX
Status IN TX
Data Stage
Setup Stage Status Stage
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Figure 34-5. S etu p Transaction Followed by a Data OUT Transaction
34.5.2.2 Data IN Transaction
Data IN transactions are used in control, isochronous, bulk and interrupt transfers and conduct the transfer of data from
the device to the host. Data IN transactions in isochronous transfer must be done using endpoints with ping-pong
attributes.
Using Endpoints Without Ping-pong Attributes
To perform a Data IN transaction using a non ping-pong endpoint:
1. The application checks if it is possible to write in the FIFO by polling TXPKTRDY in the endpoint’s UDP_ CSRx
register (TXPKTRDY must be cleared).
2. The application writes the first packet of dat a to be sent in the endpoint’s FIFO, writing zero or more byte values in
the endpoint’s UDP_ FDRx register,
3. The application notifies the USB peripheral it has finished by setting the TXPKTRDY in the endpoint’ s UDP_ CSRx
register.
4. The application is notified that the endpoint’s FIFO has been released by the USB device when TXCOMP in the
endpoint’s UDP_ CSRx register has been set. Then an interrupt for the corresponding endpoint is pending while
TXCOMP is set.
5. The microcontroller writes the second packet of data to be sent in the endpoint’s FIFO, writing zero or more byte
values in the endpoint’s UDP_ FDRx register,
6. The microcontroller notifies the USB peripheral it has finished by setting the TXPKTRDY in the endpoint’s UDP_
CSRx register.
7. The application clears the TXCOMP in the endpoint’s UDP_ CSRx.
After the last packet has been sent, the application must clear TXCOMP once this has been set.
TXCOMP is set by the USB device when it has received an ACK PID signal for the Data IN packet. An interrupt is
pending while TXCOMP is set.
Warning: TX_COMP must be cleared after TX_PKTRDY has been set.
Note: Refer to Chapter 8 of the Universal Serial Bus Specification, Rev 2.0, for more information on the Data IN proto-
col layer.
RX_Data_BKO
(UDP_CSRx)
ACK
PID
Data OUT
Data OUT
PID
NAK
PID
ACK
PID
Data Setup
Setup
PID
USB
Bus Packets
RXSETUP Flag
Set by USB Device Cleared by Firmware Set by USB
Device Peripheral
FIFO (DPR)
Content Data Setup Data
XX XX OUT
Interrupt Pending
Setup Received Setup Handled by Firmware Data Out Received
Data OUT
Data OUT
PID
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Figure 34-6. Data IN Transfer for Non Ping-pong Endpoint
Using Endpoints With Ping-pong Attribute
The use of an endpoint with ping-pong attributes is necessary during isochronous transfer. This also allows handling the
maximum bandwidth defined in the USB specification during bulk transfer. To be able to guarantee a constant or the
maximum bandwidth, the microcontroller must prepare the next data payload to be sent while the current one is being
sent by the USB device. Thus two banks of memory are used. While one is available for the microcontroller, the other
one is locked by the USB device.
Figure 34-7. Bank Swapping Data IN Transfer for Ping-pong Endpoints
When using a ping-pong endpoint, the following procedures are required to perform Data IN transactions:
USB Bus Packets Data IN 2
Data IN NAK
ACK
Data IN 1
FIFO (DPR)
Content Data IN 2Load In ProgressData IN 1
Cleared by Firmware
DPR access by the firmware
Payload in FIFO
TXCOMP Flag
(UDP_CSRx)
TXPKTRDY Flag
(UDP_CSRx)
PID
Data IN Data IN
PIDPID PIDPID ACK
PID
Prevous Data IN TX Microcontroller Load Data in FIFO Data is Sent on USB Bus
Interrupt
Pending
Interrupt Pending
Set by the firmware Set by the firmware
Cleared by
Firmware
Cleared by Hw
Cleared by Hw
DPR access by the hardware
USB Device USB Bus
Read
Write
Read and Write at the Same Time
1st Data Payload
2nd Data Payload
3rd Data Payload
3rd Data Payload
2nd Data Payload
1st Data Payload
Data IN Packet
Data IN Packet
Data IN Packet
Microcontroller
Endpoint 1
Bank 0
Endpoint 1
Bank 1
Endpoint 1
Bank 0
Endpoint 1
Bank 0
Endpoint 1
Bank 0
Endpoint 1
Bank 1
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1. The microcontroller checks if it is possible to write in the FIFO by polling TXPKTRDY to be cleared in the end-
point’s UDP_ CSRx register.
2. The microcontroller writes the first data payload to be sent in the FIFO (Bank 0), writing zero or more byte values
in the endpoint’s UDP_ FDRx register.
3. The microcontroller notifies the USB peripheral it has finished writing in Bank 0 of the FIFO by setting the TXPK-
TRDY in the endpoint’s UDP_ CSRx register.
4. Without waiting for TXPKTRDY to be cleared, the microc ontroller writes the second d ata payload to be sent in the
FIFO (Bank 1), writing zero or more byte values in the endpoint’s UDP_ FDRx register.
5. The microcontroller is notified that the first Bank has been released by the USB device when TXCOMP in the end-
point’s UDP_ CSRx register is set. An interrupt is pending while TXCOMP is being set.
6. Once the microcontroller has received TXCOMP for the first Bank, it notifies the USB device that it has prepared
the second Bank to be sent rising TXPKTRDY in the endpoint’s UDP_ CSRx register.
7. At this step, Bank 0 is available and the microcontroller can prepare a third data payload to be sent.
Figure 34-8. Data IN Trans fer for Ping-pong Endp oint
Warning: There is software critical path due to the fact that once the second bank is filled, the driver has to wait for
TX_COMP to set TX_PKTRDY. If the delay between receiving TX_COMP is set and TX_PKTRDY is set is too long,
some Data IN packets may be NACKed, reducing the bandwidth.
Warning: TX_COMP must be cleared after TX_PKTRDY has been set.
34.5.2.3 Data OUT Transaction
Data OUT transactions are used in control, isochronous, bulk and interrupt transfers and conduct the transfer of data
from the host to the device. Data OUT transactions in isochronous transfers must be done using endpoints with ping-
pong attributes.
Data OUT Transaction Without Ping-pong Attributes
To perform a Data OUT transaction, using a non ping-pong endpoint:
Data INData IN
Read by USB Device
Read by USB Device
Bank 1
Bank 0
FIFO (DPR)
TXCOMP Flag
(UDP_CSRx) Interrupt Cleared by Firmware
Set by USB
Device
TXPKTRDY Flag
(UDP_MCSRx)
ACK
PID Data IN
PID ACK
PID
Set by Firmware,
Data Payload Written in FIFO Bank 1
Cleared by USB Device,
Data Payload Fully Transmitted
Data IN
PID
USB Bus
Packets
Set by USB Device
Set by Firmware,
Data Payload Written in FIFO Bank 0
Written by
FIFO (DPR) Microcontroller
Written by
Microcontroller
Written by
Microcontroller
Microcontroller
Load Data IN Bank 0 Microcontroller Load Data IN Bank 1
USB Device Send Bank 0 Microcontroller Load Data IN Bank 0
USB Device Send Bank 1
Interrupt Pending
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1. The host generates a Data OUT packet.
2. This packet is received by the USB device endpoint. While the FIFO associated to this endpoint is being used by
the microcontroller, a NAK PID is returned to the host. Once the FIFO is available, data are written to the FIFO by
the USB device and an ACK is automatically carried out to the host.
3. The microcontroller is notified that the USB device has received a dat a payload polling RX_DATA_BK0 in the end-
point’s UDP_ CSRx register. An interrupt is pending for this endpoint while RX_DATA_BK0 is set.
4. The number of bytes available in the FIFO is made available by reading RXBYTECNT in the endpoint’s UDP_
CSRx register.
5. The microcontroller carries out data received from the endpoint’ s memory to it s memory. Data received is available
by reading the endpoint’s UDP_ FDRx register.
6. The microcontroller notifies the USB device that it has finished the transfer by clearing RX_DATA_BK0 in the end-
point’s UDP_ CSRx register.
7. A new Data OUT packet can be accepted by the USB device.
Figure 34-9. Data OUT Transfe r for No n Ping-pong Endpoints
An interrupt is pending while the flag RX_DATA_BK0 is set. Memory transfer between the USB device, the FIFO and
microcontroller memory can not be done after RX_DATA_BK0 has been cleared. Otherwise, the USB device would
accept the next Data OUT transfer and overwrite the current Data OUT packet in the FIFO.
Using Endpoints With Ping-pong Attributes
During isochronous transfer, using an endpoint with ping-pong attributes is obligatory. To be able to guarantee a
constant bandwidth, the microcontroller must read the previous data payload sent by the host, while the current data
payload is received by the USB device. Thus two banks of memory are used. While one is available for the
microcontroller, the other one is locked by the USB device.
ACK
PID
Data OUTNAK PIDPIDPIDPIDPID Data OUT2ACKData OUT Data OUT 1
USB Bus
Packets
RX_DATA_BK0
Set by USB Device Cleared by Firmware,
Data Payload Written in FIFO
FIFO (DPR)
Content Written by USB Device Microcontroller Read
Data OUT 1 Data OUT 1 Data OUT 2
Host Resends the Next Data Payload
Microcontroller Transfers Data
Host Sends Data Payload
Data OUT2 Data OUT2
Host Sends the Next Data Payload
Written by USB Device
(UDP_CSRx) Interrupt Pending
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Figure 34-10. Bank Swapping in Data OUT Transfers for Ping-pong Endpoints
When using a ping-pong endpoint, the following procedures are required to perform Data OUT transactions:
1. The host generates a Data OUT packet.
2. This packet is received by the USB device endpoint. It is written in the endpoint’s FIFO Bank 0.
3. The USB device sends an ACK PID packet to the host. The host can immediately send a second Data OUT
packet. It is accepted by the device and copied to FIFO Bank 1.
4. The microcontroller is notified that the USB device has received a data payload, polling RX_DATA_BK0 in the end-
point’s UDP_ CSRx register. An interrupt is pending for this endpoint while RX_DATA_BK0 is set.
5. The number of bytes available in the FIFO is made available by reading RXBYTECNT in the endpoint’s UDP_
CSRx register.
6. The microcontroller transfers out dat a received from the endpoint’s memory to the microcontroller’s memory. Data
received is made available by reading the endpoint’s UDP_ FDRx register.
7. The microcontroller notifies the USB peripheral device that it has finished the transfer by clearing RX_DATA_BK0
in the endpoint’s UDP_ CSRx register.
8. A third Data OUT packet can be accepted by the USB peripheral device and copied in the FIFO Bank 0.
9. If a second Data OUT packet has been received, the microcontroller is notified by the flag RX_DATA_BK1 set in
the endpoint’s UDP_ CSRx register. An interrupt is pending for this endpoint while RX_DATA_BK1 is set.
10. The microcontroller transfers out data received from the end point’s memory to the microcontroller’s memory. Data
received is available by reading the endpoint’s UDP_ FDRx register.
11. The microcontroller notifies the USB device it has finished the transfer by clearing RX_DATA_BK1 in the end-
point’s UDP_ CSRx register.
12. A fourth Data OUT packet can be accepted by the USB device and copied in the FIFO Bank 0.
USB Device USB Bus
Read
Write
Write and Read at the Same Time
1st Data Payload
2nd Data Payload
3rd Data Payload
3rd Data Payload
2nd Data Payload
1st Data Payload
Data IN Packet
Data IN Packet
Data IN Packet
Microcontroller
Endpoint 1
Bank 0
Endpoint 1
Bank 1
Endpoint 1
Bank 0
Endpoint 1
Bank 0
Endpoint 1
Bank 0
Endpoint 1
Bank 1
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Figure 34-11. Data OUT Transfer for Ping-pong Endpoint
Note: An interrupt is pending while the RX_DATA_BK0 or RX_DATA_BK1 flag is set.
Warning: When RX_DATA_BK0 and RX_DATA_BK1 are both set, there is no way to determine which one to clear first.
Thus the software must keep an internal counter to be sure to clear alternatively RX_DATA_BK0 then RX_DATA_BK1.
This situation may occur when the software application is busy elsewhere and the two banks are filled by the USB host.
Once the application comes back to the USB driver, the two flags are set.
34.5.2.4 Stall Handshake
A stall handshake can be used in one of two distinct occasions. (For more information on the stall handshake, refer to
Chapter 8 of the Universal Serial Bus Specification, Rev 2.0.)
A functional stall is used when the halt feature associated with the endpoint is set. (Refer to Chapter 9 of the
Universal Serial Bus Specification, Rev 2.0, for more information on the halt feature.)
To abort the current request, a protocol stall is used, but uniquely with control transfer.
The following procedure generates a stall packet:
1. The microcontroller sets the FORCESTALL flag in the UDP_ CSRx endpoint’s register.
2. The host receives the stall packet.
3. The microcontroller is notified that the device has sent the stall by polling the STALLSENT to be set. An endpoint
interrupt is pending while STALLSENT is set. The microcontroller must clear STALLSENT to clear the interrupt.
When a setup transaction is received after a stall handshake, STALLSENT must be cleared in order to prevent interrupts
due to STALLSENT being set.
A
P
Data OUT PID
ACK Data OUT 3
Data OUT
Data OUT 2
Data OUT
Data OUT 1
PID
Data OUT 3Data OUT 1Data OUT1
Data OUT 2 Data OUT 2
PID PID PID
ACK
Cleared by Firmware
USB Bus
Packets
RX_DATA_BK0 Flag
RX_DATA_BK1 Flag
Set by USB Device,
Data Payload Written
in FIFO Endpoint Bank 1
FIFO (DPR)
Bank 0
Bank 1
Write by USB Device Write In Progress
Read By Microcontroller
Read By Microcontroller
Set by USB Device,
Data Payload Written
in FIFO Endpoint Bank 0
Host Sends First Data Payload Microcontroller Reads Data 1 in Bank 0,
Host Sends Second Data Payload Microcontroller Reads Data2 in Bank 1,
Host Sends Third Data Payload
Cleared by Firmware
Write by USB Device
FIFO (DPR)
(UDP_CSRx)
(UDP_CSRx)
Interrupt Pending
Interrupt Pending
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Figure 34-12. Stall Handshake (Data IN Transfer)
Figure 34-13. Stall Handshake (Data OUT Transfer)
Data IN Stall PIDPID
USB Bus
Packets
Cleared by Firmware
Set by Firmware
FORCESTALL
STALLSENT Set by
USB Device
Cleared by Firmware
Interrupt Pending
Data OUT PID Stall PID
Data OUT
USB Bus
Packets
Cleared by Firmware
Set by Firmware
FORCESTALL
STALLSENT
Set by USB Device
Interrupt Pending
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34.5.2.5 Transmit Data Cancellation
Some endpoints have dual-banks whereas some endpoints have only one bank. The procedure to cancel transmission
data held in these banks is described below.
To see the organization of dual-bank availablity refer to Table 34-1 ”USB Endpoint Description”.
Endpoints Without Dual-Banks
There are two possibilities: In one case, TXPKTRDY field in UDP_CSR has already been set. In the other instance,
TXPKTRDY is not set.
TXPKTRDY is not set:
Reset the endpoint to clear the FIFO (pointers). (See, Section 34.6.9 ”UDP Reset Endpoint Register”.)
TXPKTRDY has already been set:
Clear TXPKTRDY so that no packet is ready to be sent
Reset the endpoint to clear the FIFO (pointers). (See, Section 34.6.9 ”UDP Reset Endpoint Register”.)
Endpoints With Dual-Banks
There are two possibilities: In one case, TXPKTRDY field in UDP_CSR has already been set. In the other instance,
TXPKTRDY is not set.
TXPKTRDY is not set:
Reset the endpoint to clear the FIFO (pointers). (See, Section 34.6.9 ”UDP Reset Endpoint Register”.)
TXPKTRDY has already been set:
Clear TXPKTRDY and read it back until actually read at 0.
Set TXPKTRDY and read it back until actually read at 1.
Clear TXPKTRDY so that no packet is ready to be sent.
34.5.2.6 Reset the endpoint to clear the FIFO (pointers). (See, Section 34.6.9 ”UDP Reset Endpoint Register”.)
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34.5.3 Controlling Device States
A USB device has several possible states. Refer to Chapter 9 of the Universal Serial Bus Specification, Rev 2.0.
Figure 34-14. USB Device State Diagram
Movement from one state to another depends on the USB bus state or on standard requests sent through control
transactions via the default endpoint (endpoint 0).
After a period of bus inactivity, the USB device enters Suspend Mode. Accepting Suspend/Resume requests from the
USB host is mandatory. Constraints in Suspend Mode are very strict for bus-powered applications; devices may not
consume more than 500 µA on the USB bus.
While in Suspend Mode, the host may wake up a device by sending a resume signal (bus activity) or a USB device may
send a wake up request to the host, e.g., waking up a PC by moving a USB mouse.
The wake up feature is not mandatory for all devices and must be negotiated with the host.
34.5.3.1 Not Powered State
Self powered devices can detect 5V VBUS using a PIO as described in the typical connection section. When the device
is not connected to a host, device power consumption can be reduced by disabling MCK for the UDP, disabling UDPCK
and disabling the transceiver. DDP and DDM lines are pulled down by 330 KΩ resistors.
Attached
Suspended
Suspended
Suspended
Suspended
Hub Reset
or
Deconfigured
Hub
Configured
Bus Inactive
Bus Activity
Bus Inactive
Bus Activity
Bus Inactive
Bus Activity
Bus Inactive
Bus Activity
Reset
Reset
Address
Assigned
Device
Deconfigured Device
Configured
Powered
Default
Address
Configured
Power
Interruption
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34.5.3.2 Entering Attached State
When no device is connected, the USB DP and DM signals are tied to GND by 15 KΩ pull-down resistors integrated in
the hub downstream ports. When a device is attached to a hub downstream port, the device connects a 1.5 KΩ pull-up
resistor on DP. The USB bus line goes into IDLE state, DP is pulled up by the device 1.5 KΩ resistor to 3.3V and DM is
pulled down by the 15 KΩ resistor of the host.
After pullup connection, the device enters the powered state. In this state, the UDPCK and MCK must be enabled in the
Power Management Controller. The transceiver can remain disabled.
34.5.3.3 From Powered State to Default State
After its connection to a USB host, the USB device waits for an end-of-bus reset. The unmaskable flag ENDBUSRES is
set in the register UDP_ISR and an interrupt is triggered.
Once the ENDBUSRES interrupt has been triggered, the device enters Default State. In this state, the UDP software
must:
Enable the default endpoint, setting the EPEDS flag in the UDP_CSR[0] register and, optionally, enabling the
interrupt for endpoint 0 by writing 1 to the UDP_IER register. The enumeration then begins by a control transfer.
Configure the interrupt mask register which has been reset by the USB reset detection
Enable the transceiver clearing the TXVDIS flag in the UDP_TXVC register.
In this state UDPCK and MCK must be enabled.
Warning: Each time an ENDBUSRES interrupt is triggered, the Interrupt Mask Register and UDP_CSR registers have
been reset.
34.5.3.4 From Default State to Address State
After a set address standard device request, the USB host peripheral enters the address state.
Warning: Before the device enters in address state, it must achieve the Status IN transaction of the control transfer, i.e.,
the UDP device sets its new address once the TXCOMP flag in the UDP_CSR[0] register has been received and cleared.
To move to address state, the driver software sets the FADDEN flag in the UDP_GLB_STAT register, sets its new
address, and sets the FEN bit in the UDP_FADDR register.
34.5.3.5 From Address State to Configured State
Once a valid Set Configuration standard request has been received and acknowledged, the device enables endpoints
corresponding to the current configuration. This is done by setting the EPEDS and EPTYPE fields in the UDP_CSRx
registers and, optionally, enabling corresponding interrupts in the UDP_IER register.
34.5.3.6 Entering in Suspend State
When a Suspend (no bus activity on the USB bus) is detected, the RXSUSP signal in the UDP_ISR register is set. This
triggers an interrupt if the corresponding bit is set in the UDP_IMR register.This flag is cleared by writing to the UDP_ICR
register. Then the device enters Suspend Mode.
In this state bus powered devices must drain less than 500uA from the 5V VBUS. As an example, the microcontroller
switches to slow clock, disables the PLL and main oscillator, and goes into Idle Mode. It may also switch off other devices
on the board.
The USB device peripheral clocks can be switched off. Resume event is asynchronously detected. MCK and UDPCK
can be switched off in the Power Management controller and the USB transceiver can be disabled by setting the TXVDIS
field in the UDP_TXVC register.
Warning: Read, write operations to the UDP registers are allowed only if MCK is enabled for the UDP peripheral.
Switching off MCK for the UDP peripheral must be one of the last operations after writing to the UDP_TXVC and
acknowledging the RXSUSP.
34.5.3.7 Receiving a Host Resume
In suspend mode, a resume event on the USB bus line is detected asynchronously, transceiver and clocks are disabled
(however the pullup shall not be removed).
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Once the resume is detected on the bus, the WAKEUP signal in the UDP_ISR is set. It may generate an interrupt if the
corresponding bit in the UDP_IMR register is set. This interrupt may be used to wake up the core, enable PLL and main
oscillators and configure clocks.
Warning: Read, write operations to the UDP registers are allowed only if MCK is enabled for the UDP peripheral. MCK
for the UDP must be enabled before clearing the WAKEUP bit in the UDP_ICR register and clearing TXVDIS in the
UDP_TXVC register.
34.5.3.8 Sending a Device Remote Wakeup
In Suspend state it is possible to wake up the host sending an external resume.
The device must wait at least 5 ms after being entered in suspend before sending an external resume.
The device has 10 ms from the moment it starts to drain current and it forces a K state to resume the host.
The device must force a K state from 1 to 15 ms to resume the host
To force a K state to the bus (DM at 3.3V and DP tied to GND), it is possible to use a transistor to connect a pullup on
DM. The K state is obtained by disabling the pullup on DP and enabling the pullup on DM. This should be under the
control of the application.
Figure 34-15. Board Schematic to Drive a K State
3V3
PIO
1.5 K
0: Force Wake UP (K State)
1: Normal Mode
DM
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34.6 USB Device Port (UDP) User Interface
WARNING: The UDP peripheral clock in the Power Management Controller (PMC) must be enabled before any read/write opera-
tions to the UDP registers including the UDP_TXCV register.
Notes: 1. Reset values are not defined for UDP_ISR.
2. See Warning above the ”Register Mapping” on this page.
Table 34-4. Regist er Mapping
Offset Register Name Access Reset
0x000 Frame Number Registe r UDP_FRM_NUM Read-only 0x0000_0000
0x004 Global State Register UD P_GLB_STAT Read-write 0x0000_0000
0x008 Function Address Register UDP_FADDR Read-write 0x0000_0100
0x00C Reserved – – –
0x010 Interrupt Enable Register UDP_IER Write-only
0x014 Interrupt Disable Register UDP_IDR Write-only
0x018 Interrupt Mask Register UDP_IMR Read-only 0x0000_1200
0x01C Interrupt Status Register UDP_ISR Read-only –(1)
0x020 Interrupt Clear Register UDP_ICR Write-only
0x024 Reserved – – –
0x028 Reset Endpoint Register UDP_RST_EP Read-write 0x0000_0000
0x02C Reserved – – –
0x030 + 0x4 * ( ept_num - 1 ) Endpoint Control and Status Register UDP_CSR Read-write 0x0000_0000
0x050 + 0x4 * ( ept_num - 1 ) Endpoint FIFO Data Register UDP_FDR Read-write 0x00 00_0000
0x070 Reserved – – –
0x074 Transceiver Control Register UDP_TXVC(2) Read-write 0x0000_0000
0x078 - 0xFC Reserved – – –
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34.6.1 UDP Frame Number Register
Register Name: UDP_ FRM_NUM
Access Type: Read-only
• FRM_NUM[10:0]: Frame Number as Defined in the Packet Field Formats
This 11-bit value is incremented by the host on a per frame basis. This value is updated at each start of frame.
Value Updated at the SOF_EOP (Start of Frame End of Packet).
• FRM_ERR: Frame Error
This bit is set at SOF_EOP when the SOF packet is received containing an error.
This bit is reset upon receipt of SOF_PID.
• FRM_OK: Frame OK
This bit is set at SOF_EOP when the SOF packet is received without any error.
This bit is reset upon receipt of SOF_PID (Packet Identification).
In the Interrupt Status Register, the SOF interrupt is updated upon receiving SOF_PID. This bit is set without waiting for EOP.
Note: In th e 8-bit Register Interface, FRM_OK is bit 4 of FRM_NUM_H and FRM_ERR is bit 3 of FRM_NUM_L.
31 30 29 28 27 26 25 24
--- --- --- --- --- --- --- ---
23 22 21 20 19 18 17 16
––––––FRM_OKFRM_ERR
15 14 13 12 11 10 9 8
––––– FRM_NUM
76543210
FRM_NUM
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34.6.2 UDP Glo ba l State Register
Register Name: UDP_ GLB_STAT
Access Type: Read-write
This register is used to get and set the device state as specified in Chapter 9 of the USB Serial Bus Specification, Rev.2.0.
• FADDEN: Function Address Enable
Read:
0 = Device is not in address state.
1 = Device is in address state.
Write:
0 = No effect, only a reset can bring back a device to the default state.
1 = Sets device in address state. This occurs after a successful Set Address request. Beforehand, the UDP_ FADDR register
must have been initialized with Set Address parameters. Set Address must complete the Status Stage before setting FADDEN.
Refer to chapter 9 of the Universal Serial Bus Specification, Rev. 2.0 for more details.
• CONFG: Configured
Read:
0 = Device is not in configured state.
1 = Device is in configured state.
Write:
0 = Sets device in a non configured state
1 = Sets device in configured state.
The device is set in configured state when it is in address state and receives a successful Set Configuration request. Refer to
Chapter 9 of the Universal Serial Bus Specification, Rev. 2.0 for more details.
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––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
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––––––CONFGFADDEN
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34.6.3 UDP Function Address Register
Register Name: UDP_ FADDR
Access Type: Read-write
• FADD[6:0]: Function Address Value
The Function Address Value must be programmed by firmware once the device receives a set address request from the host, and
has achieved the status stage of the no-data control sequence. Refer to the Universal Serial Bus Specification, Rev. 2.0 for more
information. After power up or reset, the function address value is set to 0.
• FEN: Function Enable
Read:
0 = Function endpoint disabled.
1 = Function endpoint enabled.
Write:
0 = Disables function endpoint.
1 = Default value.
The Function Enable bit (FEN) allows the microcontroller to enable or disable the function endpoints. The microcontroller sets this
bit after receipt of a reset from the host. Once this bit is set, the USB device is able to accept and transfer data packets from and
to the host.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––––FEN
76543210
–FADD
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34.6.4 UDP Interrupt Enable Register
Register Name: UDP_ IER
Access Type: Write-only
• EP0INT: Enable Endpoint 0 Interrupt
• EP1INT: Enable Endpoint 1 Interrupt
• EP2INT: Enable Endpoint 2Interrupt
• EP3INT: Enable Endpoint 3 Interrupt
• EP4INT: Enable Endpoint 4 Interrupt
• EP5INT: Enable Endpoint 5 Interrupt
0 = No effect.
1 = Enables corresponding Endpoint Interrupt.
• RXSUSP: Enable UDP Suspend Interrupt
0 = No effect.
1 = Enables UDP Suspend Interrupt.
• RXRSM: Enable UDP Resume Interrupt
0 = No effect.
1 = Enables UDP Resume Interrupt.
• SOFINT: Enable Start Of Frame Interrupt
0 = No effect.
1 = Enables Start Of Frame Interrupt.
• WAKEUP: Enable UDP bus Wakeup Interrupt
0 = No effect.
1 = Enables USB bus Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – WAKEUP – SOFINT – RXRSM RXSUSP
76543210
EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT
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34.6.5 UDP Interrupt Disable Register
Register Name: UDP_ IDR
Access Type: Write-only
• EP0INT: Disable Endpoint 0 Interrupt
• EP1INT: Disable Endpoint 1 Interrupt
• EP2INT: Disable Endpoint 2 Interrupt
• EP3INT: Disable Endpoint 3 Interrupt
• EP4INT: Disable Endpoint 4 Interrupt
• EP5INT: Disable Endpoint 5 Interrupt
0 = No effect.
1 = Disables corresponding Endpoint Interrupt.
• RXSUSP: Disable UDP Suspend Interrupt
0 = No effect.
1 = Disables UDP Suspend Interrupt.
• RXRSM: Disable UDP Resume Interrupt
0 = No effect.
1 = Disables UDP Resume Interrupt.
• SOFINT: Disable Start Of Frame Interrupt
0 = No effect.
1 = Disables Start Of Frame Interrupt
• WAKEUP: Disable USB Bus Interrupt
0 = No effect.
1 = Disables USB Bus Wakeup Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – WAKEUP – SOFINT – RXRSM RXSUSP
76543210
EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT
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34.6.6 UDP Interrupt Mask Register
Register Name: UDP_ IMR
Access Type: Read-only
• EP0INT: Mask Endpoint 0 Interrupt
• EP1INT: Mask Endpoint 1 Interrupt
• EP2INT: Mask Endpoint 2 Interrupt
• EP3INT: Mask Endpoint 3 Interrupt
• EP4INT: Mask Endpoint 4 Interrupt
• EP5INT: Mask Endpoint 5 Interrupt
0 = Corresponding Endpoint Interrupt is disabled.
1 = Corresponding Endpoint Interrupt is enabled.
• RXSUSP: Mask UDP Suspend Interrupt
0 = UDP Suspend Interrupt is disabled.
1 = UDP Suspend Interrupt is enabled.
• RXRSM: Mask UDP Resume Interrupt.
0 = UDP Resume Interrupt is disabled.
1 = UDP Resume Interrupt is enabled.
• SOFINT: Mask Start Of Frame Interrupt
0 = Start of Frame Interrupt is disabled.
1 = Start of Frame Interrupt is enabled.
• BIT12: UDP_IMR Bit 12
Bit 12 of UDP_IMR cannot be masked and is always read at 1.
• WAKEUP: USB Bus WAKEUP Interrupt
0 = USB Bus Wakeup Interrupt is disabled.
1 = USB Bus Wakeup Interrupt is enabled.
Note: When the USB block is in suspend mode, the application may power down the USB logic. In this case, any USB
HOST resume request that is made must be taken into account and, thus, the reset value of the RXRSM bit of the
register UDP_ IMR is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – WAKEUP – SOFINT – RXRSM RXSUSP
76543210
EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT
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34.6.7 UDP Interrupt Status Register
Register Name: UDP_ ISR
Access Type: Read-only
• EP0INT: Endpoint 0 Interrupt Status
• EP1INT: Endpoint 1 Interrupt Status
• EP2INT: Endpoint 2 Interrupt Status
• EP3INT: Endpoint 3 Interrupt Status
• EP4INT: Endpoint 4 Interrupt Status
• EP5INT: Endpoint 5 Interrupt Status
0 = No Endpoint0 Interrupt pending.
1 = Endpoint0 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_ CSR0:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP0INT is a sticky bit. Interrupt remains valid until EP0INT is cleared by writing in the corresponding UDP_ CSR0 bit.
• RXSUSP: UDP Suspend Interrupt Status
0 = No UDP Suspend Interrupt pending.
1 = UDP Suspend Interrupt has been raised.
The USB device sets this bit when it detects no activity for 3ms. The USB device enters Suspend mode.
• RXRSM: UDP Resume Interrupt Status
0 = No UDP Resume Interrupt pending.
1 =UDP Resume Interrupt has been raised.
The USB device sets this bit when a UDP resume signal is detected at its port.
After reset, the state of this bit is undefined, the application must clear this bit by setting the RXRSM flag in the UDP_ ICR
register.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – WAKEUP ENDBUSRES SOFINT – RXRSM RXSUSP
76543210
EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT
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• SOFINT: Start of Frame Interrupt Status
0 = No Start of Frame Interrupt pending.
1 = Start of Frame Interrupt has been raised.
This interrupt is raised each time a SOF token has been detected. It can be used as a synchronization signal by using
isochronous endpoints.
• ENDBUSRES: End of BUS Reset Interrupt Status
0 = No End of Bus Reset Interrupt pending.
1 = End of Bus Reset Interrupt has been raised.
This interrupt is raised at the end of a UDP reset sequence. The USB device must prepare to receive requests on the endpoint 0.
The host starts the enumeration, then performs the configuration.
• WAKEUP: UDP Resume Interrupt Status
0 = No Wakeup Interrupt pending.
1 = A Wakeup Interrupt (USB Host Sent a RESUME or RESET) occurred since the last clear.
After reset the state of this bit is undefined, the application must clear this bit by setting the WAKEUP flag in the UDP_ ICR
register.
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34.6.8 UDP Interrupt Clear Register
Register Name: UDP_ ICR
Access Type: Write-only
• RXSUSP: Clear UDP Suspend Interrupt
0 = No effect.
1 = Clears UDP Suspend Interrupt.
• RXRSM: Clear UDP Resume Interrupt
0 = No effect.
1 = Clears UDP Resume Interrupt.
• SOFINT: Clear Start Of Frame Interrupt
0 = No effect.
1 = Clears Start Of Frame Interrupt.
• ENDBUSRES: Cl ear End of Bus Reset Interrupt
0 = No effect.
1 = Clears End of Bus Reset Interrupt.
• WAKEUP: Clear Wakeup Interrupt
0 = No effect.
1 = Clears Wakeup Interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – WAKEUP ENDBUSRES SOFINT – RXRSM RXSUSP
76543210
––––––––
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34.6.9 UDP Reset Endpoint Register
Register Name: UDP_ RST_EP
Access Type: Read-write
• EP0: Reset Endpoint 0
• EP1: Reset Endpoint 1
• EP2: Reset Endpoint 2
• EP3: Reset Endpoint 3
• EP4: Reset Endpoint 4
• EP5: Reset Endpoint 5
This flag is used to reset the FIFO associated with the endpoint and the bit RXBYTECOUNT in the register UDP_CSRx.It also
resets the data toggle to DATA0. It is useful after removing a HALT condition on a BULK endpoint. Refer to Chapter 5.8.5 in the
USB Serial Bus Specification, Rev.2.0.
Warning: This flag must be cleared at the end of the reset. It does not clear UDP_ CSRx flags.
0 = No reset.
1 = Forces the corresponding endpoint FIF0 pointers to 0, therefore RXBYTECNT field is read at 0 in UDP_ CSRx register.
Reseting the endpoint is a two-step operation:
1. Set the corresponding EPx field.
2. Clear the corresponding EPx field.
31 30 29 28 27 26 25 24
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23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
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EP5 EP4 EP3 EP2 EP1 EP0
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34.6.10 UDP Endpoint Control and Status Register
Register Name: UDP_ CSRx [x = 0..5]
Access Type: Read-write
WARNING: Due to synchronization between MCK and UDPCK, the software application must wait for the end of the write opera-
tion before executing another write by polling the bits which must be set/cleared.
//! Clear flags of UDP UDP_CSR register and waits for synchronization
#define Udp_ep_clr_flag(pInterface, endpoint, flags) { \
pInterface->UDP_CSR[endpoint] &= ~(flags); \
while ( (pInterface->UDP_CSR[endpoint] & (flags)) == (flags) ); \
}
//! Set flags of UDP UDP_CSR register and waits for synchronization
#define Udp_ep_set_flag(pInterface, endpoint, flags) { \
pInterface->UDP_CSR[endpoint] |= (flags); \
while ( (pInterface->UDP_CSR[endpoint] & (flags)) != (flags) ); \
}
Note: In a preemptive environment, set or clear the flag and wait for a time of 1 UDPCK clock cycle and 1peripheral clock
cycle. However, RX_DATA_BLK0, TXPKTRDY, RX_DATA_BK1 require wait times of 3 UDPCK clock cycles and 3
peripheral clock cycles before accessing DPR.
• TXCOMP: Generates an IN Packet with Data Previously Written in the DPR
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware):
0 = Clear the flag, clear the interrupt.
1 = No effect.
Read (Set by the USB peripheral):
0 = Data IN transaction has not been acknowledged by the Host.
1 = Data IN transaction is achieved, acknowledged by the Host.
After having issued a Data IN transaction setting TXPKTRDY, the device firmware waits for TXCOMP to be sure that the ho st has
acknowledged the transaction.
31 30 29 28 27 26 25 24
––––– RXBYTECNT
23 22 21 20 19 18 17 16
RXBYTECNT
15 14 13 12 11 10 9 8
EPEDS – – – DTGLE EPTYPE
76543210
DIR RX_DATA_
BK1 FORCE
STALL TXPKTRDY STALLSENT
ISOERROR RXSETUP RX_DATA_
BK0 TXCOMP
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• RX_DATA_BK0: Receive Data Bank 0
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware):
0 = Notify USB peripheral device that data have been read in the FIFO's Bank 0.
1 = To leave the read value unchanged.
Read (Set by the USB peripheral):
0 = No data packet has been received in the FIFO's Bank 0.
1 = A data packet has been received, it has been stored in the FIFO's Bank 0.
When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to the
microcontroller memory. The number of bytes received is available in RXBYTCENT field. Bank 0 FIFO values are read through
the UDP_ FDRx register. Once a transfer is done, the device firmware must release Bank 0 to the USB peripheral device by clear-
ing RX_DATA_BK0.
After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before accessing
DPR.
• RXSETUP: Received Setup
This flag generates an interrupt while it is set to one.
Read:
0 = No setup packet available.
1 = A setup data packet has been sent by the host and is available in the FIFO.
Write:
0 = Device firmware notifies the USB peripheral device that it has read the setup data in the FIFO.
1 = No effect.
This flag is used to notify the USB device firmware that a valid Setup data packet has been sent by the host and successfully
received by the USB device. The USB device firmware may transfer Setup data from the FIFO by reading the UDP_ FDRx regis-
ter to the microcontroller memory. Once a transfer has been done, RXSETUP must be cleared by the device firmware.
Ensuing Data OUT transaction is not accepted while RXSETUP is set.
• STALLSENT: Sta ll Sent (Control, Bulk Interrupt Endpoints) / ISOERR OR (Isochronous Endpoints)
This flag generates an interrupt while it is set to one.
STALLSENT: This ends a STALL handshake.
Read:
0 = The host has not acknowledged a STALL.
1 = Host has acknowledged the stall.
Write:
0 = Resets the STALLSENT flag, clears the interrupt.
1 = No effect.
This is mandatory for the device firmware to clear this flag. Otherwise the interrupt remains.
Refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the STALL
handshake.
ISOERROR: A CRC error has been detected in an isochronous transfer.
Read:
0 = No error in the previous isochronous transfer.
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1 = CRC error has been detected, data available in the FIFO are corrupted.
Write:
0 = Resets the ISOERROR flag, clears the interrupt.
1 = No effect.
• TXPKTRDY: Transmit Packet Ready
This flag is cleared by the USB device.
This flag is set by the USB device firmware.
Read:
0 = Can be set to one to send the FIFO data.
1 = The data is waiting to be sent upon reception of token IN.
Write:
0 = Can be written if old value is zero.
1 = A new data payload is has been written in the FIFO by the firmware and is ready to be sent.
This flag is used to generate a Data IN transaction (device to host). Device firmware checks that it can write a data payload in the
FIFO, checking that TXPKTRDY is cleared. Transfer to the FIFO is done by writing in the UDP_ FDRx register. Once the data
payload has been transferred to the FIFO, the firmware notifies the USB device setting TXPKTRDY to one. USB bus transactions
can start. TXCOMP is set once the data payload has been received by the host.
After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before accessing
DPR.
• FORCESTALL: Force Stall (used by Control, Bulk and Isochronous Endpoints)
Read:
0 = Normal state.
1 = Stall state.
Write:
0 = Return to normal state.
1 = Send STALL to the host.
Refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the STALL
handshake.
Control endpoints: During the data stage and status stage, this bit indicates that the microcontroller cannot complete the request.
Bulk and interrupt endpoints: This bit notifies the host that the endpoint is halted.
The host acknowledges the STALL, device firmware is notified by the STALLSENT flag.
• RX_DATA_BK1: Receive Data Bank 1 (only used by endpoints with ping-pong attributes)
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware):
0 = Notifies USB device that data have been read in the FIFO’s Bank 1.
1 = No effect.
Read (Set by the USB peripheral):
0 = No data packet has been received in the FIFO's Bank 1.
1 = A data packet has been received, it has been stored in FIFO's Bank 1.
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When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to micro-
controller memory. The number of bytes received is available in RXBYTECNT field. Bank 1 FIFO values are read through UDP_
FDRx register. Once a transfer is done, the device firmware must release Bank 1 to the USB device by clearing RX_DATA_BK1.
• DIR: Transfer Direction (only available for co ntrol endpoints)
Read/Write
0 = Allows Data OUT transactions in the control data stage.
1 = Enables Data IN transactions in the control data stage.
Refer to Chapter 8.5.3 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the control data stage.
This bit must be set before UDP_ CSRx/RXSETUP is cleared at the end of the setup stage. According to the request sent in the
setup data packet, the data stage is either a device to host (DIR = 1) or host to device (DIR = 0) data transfer. It is not necessary
to check this bit to reverse direction for the status stage.
• EPTYPE[2:0]: Endpoint Type
• DTGLE: Data Toggle
Read-only
0 = Identifies DATA0 packet.
1 = Identifies DATA1 packet.
Refer to Chapter 8 of the Universal Serial Bus Specification, Rev. 2.0 for more information on DATA0, DATA1 packet definitions.
• EPEDS: Endpoint Enable Disable
Read:
0 = Endpoint disabled.
1 = Endpoint enabled.
Write:
0 = Disables endpoint.
1 = Enables endpoint.
Control endpoints are always enabled. Reading or writing this field has no effect on control endpoints.
Note: After reset, all endpoints are configured as control endpoints (zero).
• RXBYTECNT[10:0]: Number of Bytes Available in the FIFO
Read-only
When the host sends a data packet to the device, the USB device stores the data in the FIFO and notifies the microcontroller. T he
microcontroller can load the data from the FIFO by reading RXBYTECENT bytes in the UDP_ FDRx register.
Read/Write
000 Control
001 Isochron ous OUT
101 Isochron ous IN
010 Bulk OUT
110 Bulk IN
011 Interrupt OUT
111 Interrupt IN
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34.6.11 UDP FIFO Data Register
Register Name: UDP_ FDRx [x = 0..5]
Access Type: Read-write
• FIFO_D ATA[7:0]: FIFO Data Value
The microcontroller can push or pop values in the FIFO through this register.
RXBYTECNT in the corresponding UDP_ CSRx register is the number of bytes to be read from the FIFO (sent by the host).
The maximum number of bytes to write is fixed by the Max Packet Size in the Standard Endpoint Descriptor. It can not be more
than the physical memory size associated to the endpoint. Refer to the Universal Serial Bus Specification, Rev. 2.0 for more
information.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
FIFO_DATA
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SAM7X Series [DATASHEET]
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34.6.12 UDP Transceiver Control Register
Register Name: UDP_ TXVC
Access Type: Read-write
WARNING: The UDP peripheral clock in the Power Management Controller (PMC) must be enabled before any read/write opera-
tions to the UDP registers including the UDP_TXCV register.
• TXVDIS: Transceiver Disable
When UDP is disabled, power consumption can be reduced significantly by disabling the embedded transceiver. This can be
done by setting TXVDIS field.
To enable the transceiver, TXVDIS must be cleared.
NOTE: If the USB pullup is not connected on DP, the user should not write in any UDP register other than the UDP_ TXVC regis-
ter. This is because if DP and DM are floating at 0, or pulled down, then SE0 is received by the device with the consequence of a
USB Reset.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––– TXVDIS
76543210
––––––––
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SAM7X Series [DATASHEET]
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35. Analog-to-Digital Converter (ADC)
35.1 Overview
The ADC is based on a Successive Approximation Register (SAR) 10-bit Analog-to-Digital Converter (ADC). It also
integrates an 8-to-1 analog multiplexer, making possible the analog-to-digital conversions of 8 analog lines. The
conversions extend from 0V to ADVREF.
The ADC supports an 8-bit or 10-bit resolution mode, and conversion results are reported in a common register for all
channels, as well as in a channel-dedicated register. Software trigger, external trigger on rising edge of the ADTRG pin
or internal triggers from Timer Counter output(s) are configurable.
The ADC also integrates a Sleep Mode and a conversion sequencer and connects with a PDC channel. These features
reduce both power consumption and processor intervention.
Finally, the user can configure ADC timings, such as Startup Time and Sample & Hold Time.
35.2 Block Diagram
Figure 35-1. Analog-to-Digital Converter Block Diagram
ADC Interrupt
ADTRG
VDDIN
ADVREF
GND
Trigger
Selection Control
Logic
Successive
Approximation
Register
Analog-to-Digital
Converter
Timer
Counter
Channels
User
Interface
AIC
Peripheral Bridge
APB
PDC
ASB
Dedicated
Analog
Inputs
Analog Inputs
Multiplexed
with I/O lines
AD-
AD-
AD-
PIO
AD-
AD-
AD-
ADC Controller
PMC
MCK
ADC cell
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35.3 Signal Description
35.4 Product Dependencies
35.4.1 Power Management
The ADC Controller clock (MCK) is always clocked.
35.4.2 Interrupt Sources
The ADC interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the ADC
interrupt requires the AIC to be programmed first.
35.4.3 Analog Inputs
The analog input pins can be multiplexed with PIO lines. In this case, the assignment of the ADC input is automatically
done as soon as the corresponding channel is enabled by writing the register ADC_CHER. By default, after reset, the
PIO line is configured as input with its pull-up enabled and the ADC input is connected to the GND.
35.4.4 I/O Lines
The pin ADTRG may be shared with other peripheral functions through the PIO Controller. In this case, the PIO
Controller should be set accordingly to assign the pin ADTRG to the ADC function.
35.4.5 Timer Triggers
Timer Counters may or may not be used as hardware triggers depending on user requirements. Thus, some or a ll of the
timer counters may be non-connected.
35.4.6 Conversion Performances
For performance and electrical characteristics of the ADC, see the DC Characteristics section.
Table 35-1. ADC Pin Description
Pin Name Description
ADVREF Reference voltage
AD0 - AD7Analog input channels
ADTRG External trigger
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35.5 Functional Description
35.5.1 Analog-to-digital Conversion
The ADC uses the ADC Clock to perform conversions. Converting a single analog value to a 10-bit digital data requires
Sample and Hold Clock cycles as defined in the field SHTIM of the “ADC Mode Register” on page 472 and 10 ADC Clock
cycles. The ADC Clock frequency is selected in the PRESCAL field of the Mode Register (ADC_MR).
The ADC clock range is between MCK/2, if PRESCAL is 0, and MCK/128, if PRESCAL is set to 63 (0x3F). PRESCAL
must be programmed in order to provide an ADC clock frequency according to the parameters given in the Product
definition section.
35.5.2 Conversion Reference
The conversion is performed on a full range between 0V and the refe rence voltage pin ADVREF. Analog inputs between
these voltages convert to values based on a linear conversion.
35.5.3 Conversion Resolution
The ADC supports 8-bit or 10-bit resolutions. The 8-bit selection is performed by setting the bit LOWRES in the ADC
Mode Register (ADC_MR). By default, after a reset, the resolution is the highest and the DATA field in the data registers
is fully used. By setting the bit LOWRES, the ADC switches in the lowest resolution and the conversion results can be
read in the eight lowest significant bits of the data registers. The two highest bits of the DATA field in the corresponding
ADC_CDR register and of the LDATA field in the ADC_LCDR register read 0.
Moreover, when a PDC channel is connected to the ADC, 10-bit resolution sets the transfer request sizes to 16-bit.
Setting the bit LOWRES automatically switches to 8-bit data transfers. In this case, the destination buffers are optimized.
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35.5.4 Conversion Results
When a conversion is completed, the resulting 10-bit digital value is stored in the Channel Data Register (ADC_CDR) of
the current channel and in the ADC Last Converted Data Register (ADC_LCDR).
The channel EOC bit in the Status Register (ADC_SR) is set and the DRDY is set. In the case of a connected PDC
channel, DRDY rising triggers a data transfer request. In any case, either EOC and DRDY can trigger an interrupt.
Reading one of the ADC_CDR registers clears the corresponding EOC bit. Reading ADC_LCDR clears the DRDY bit
and the EOC bit corresponding to the last converted channel.
Figure 35-2. EOCx and DRDY Flag Beha vior
Conv ersion Time
Read the ADC_CDRx
EOCx
DRDY
Read the ADC_LCDR
CHx
(ADC_CHSR)
(ADC_SR)
(ADC_SR)
Write the ADC_CR
with START = 1
Conv ersion Time
Write the ADC_CR
with START = 1
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If the ADC_CDR is not read before further incoming data is converted, the corresponding Overrun Error (OVRE) flag is
set in the Status Register (ADC_SR).
In the same way, new data converted when DRDY is high sets the bit GOVRE (General Overrun Error) in ADC_SR.
The OVRE and GOVRE flags are automatically cleared when ADC_SR is read.
Figure 35-3. GOVRE and OVREx Flag Behavior
Warning: If the corresponding channel is disabled during a conversion or if it is disabled and then reenabled during a
conversion, its associated data and its corresponding EOC and OVRE flags in ADC_SR are unpredictable.
EOC0
GOVRE
CH0
(ADC_CHSR)
(ADC_SR)
(ADC_SR)
ADTRG
EOC1
CH1
(ADC_CHSR)
(ADC_SR)
OVRE0
(ADC_SR)
Undefined Data Data A Data B
ADC_LCDR
Undefined Data Data A
ADC_CDR0
Undefined Data Data B
ADC_CDR1
Data C
Data C
Conversion
Conversion
Read ADC_SR
DRDY
(ADC_SR)
Read ADC_CDR1
Read ADC_CDR0
Conversion
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35.5.5 Conversion Triggers
Conversions of the active analog channels are started with a software or a hardware trigger. The software trigger is
provided by writing the Control Register (ADC_CR) with the bit START at 1.
The hardware trigger can be one of the TIOA outputs of the Timer Counter channels, or the external trigger input of the
ADC (ADTRG). The hardware trigger is selected with the field TRGSEL in the Mode Register (ADC_MR). The selected
hardware trigger is enabled with the bit TRGEN in the Mode Register (ADC_MR).
If a hardware trigger is selected, the start of a conversion is triggered after a delay starting at each rising edge of the
selected signal. Due to asynchronism handling, the delay may vary in a range of 2 MCK clock periods to 1 ADC clock
period.
If one of the TIOA outputs is selected, the corresponding Timer Counter channel must be programmed in Waveform
Mode.
Only one start command is necessary to initiate a conversion sequence on all the channels. The ADC hardware logic
automatically performs the conversions on the active channels, then waits for a new request. The Channel Enable
(ADC_CHER) and Channel Disable (ADC_CHDR) Registers enable the analog channels to be enabled or disabled
independently.
If the ADC is used with a PDC, only the transfers of converted data from enabled channels are performed and the
resulting data buffers should be interpreted accordingly.
Warning: Enabling hardware triggers does not disable the software trigger functionality. Thus, if a hardware trigger is
selected, the start of a conversion can be initiated either by the hardware or the software trigger.
35.5.6 Sleep Mode and Conversion Sequencer
The ADC Sleep Mode maximizes power saving by automatically deactivating the ADC when it is not being used for
conversions. Sleep Mode is selected by setting the bit SLEEP in the Mode Register ADC_MR.
The SLEEP mode is automatically managed by a conversion sequencer, which can automatically process the
conversions of all channels at lowest power consumption.
When a start conversion request occurs, the ADC is automatically activated. As the analog cell requires a start-up time,
the logic waits during this time and starts the conversion on the enabled channels. When all conversions are complete,
the ADC is deactivated until the next trigger. Triggers occurring during the sequence are not taken into account.
The conversion sequencer allows automatic processing with minimum processor intervention and optimized power
consumption. Conversion sequences can be performed periodically using a Timer/Counter output. The periodic
acquisition of several samples can be processed automatically without any intervention of the processor thanks to the
PDC.
Note: The reference voltage pins always remain connected in normal mode as in sleep mode.
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35.5.7 ADC Timings
Each ADC has its own minimal Startup Time that is programmed through the field STARTUP in the Mode Register
ADC_MR.
In the same way, a minimal Sample and Hold Time is necessary for the ADC to guarantee the best converted final value
between two channels selection. This time has to be programmed through the bitfield SHTIM in the Mode Register
ADC_MR.
Warning: No input buffer amplifier to isolate the source is included in the ADC. This must be taken into consideration to
program a precise value in the SHTIM field. See the section, ADC Characteristics in the product datasheet.
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35.6 Analog-to-Digital Converter (ADC) User Interface
Table 35-2. Regist er Mapping
Offset Register Name Access Reset
0x00 Control Register ADC_CR Write-only –
0x04 Mode Register ADC_MR Read-write 0x00000000
0x08 Reserved – – –
0x0C Reserved – – –
0x10 Channel Enable Register ADC_CHER Wr ite-only –
0x14 Channel Disable Register ADC_CHDR Write-only –
0x18 Channel Status Register ADC_CHSR Read-only 0x00000000
0x1C Status Register ADC_SR Read-only 0x000C0000
0x20 Last Converted Data Register ADC_LCDR Read-only 0x00000000
0x24 Interr upt Enable Register ADC_IER Write-only –
0x28 Interr upt Disable Register ADC_IDR Write-only –
0x2C Interrupt Mask Register ADC_IMR Read-only 0x00000000
0x30 Channel Data Register 0 ADC_CDR0 Read-only 0x00000000
0x34 Channel Data Register 1 ADC_CDR1 Read-only 0x00000000
... ... ... ... ...
0x4C Channel Data Reg ister 7 ADC_CDR7 Read-only 0x00000000
0x50 - 0xFC Reserved – – –
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35.6.1 ADC Control Register
Register Name: ADC_CR
Access Type: Write-only
• SWRST: Software Reset
0 = No effect.
1 = Resets the ADC simulating a hardware reset.
• START: Start Conversion
0 = No effect.
1 = Begins analog-to-digital conversion.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––STARTSWRST
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35.6.2 ADC Mode Register
Register Name: ADC_MR
Access Type: Read/Write
• TRGEN: Trigger Enable
• TRGSEL: Trigger Selection
• LOWRES: Resolution
• SLEEP: Sleep Mode
31 30 29 28 27 26 25 24
–––– SHTIM
23 22 21 20 19 18 17 16
–STARTUP
15 14 13 12 11 10 9 8
PRESCAL
76543210
– – SLEEP LOWRES TRGSEL TRGEN
TRGEN Selected TRGEN
0 Hardware triggers are disabled. Starting a conversion is only possible by software.
1 Hardware trigger selected by TRGSEL field is enabled.
TRGSEL Selected TRGSEL
000TIOA Ouput of the Timer Counter Channel 0
001TIOA Ouput of the Timer Counter Channel 1
010TIOA Ouput of the Timer Counter Channel 2
011Reserved
100Reserved
101Reserved
110External trigger
111Reserved
LOWRES Selected Resolution
0 10-bit resolution
1 8-bit resolution
SLEEP Selected Mode
0 Nor mal Mode
1 Sleep Mode
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• PRESCAL: Prescaler Rate Selection
ADCClock = MCK / ( (PRESCAL+1) * 2 )
• STARTUP: Start Up Time
Startup Time = (STARTUP+1) * 8 / ADCClock
• SHTIM: Sample & Hold Time
Sample & Hold Time = SHTIM/ADCClock
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35.6.3 ADC Channel Enable Register
Register Name: ADC_CHER
Access Type: Write-only
• CHx: Channel x Enabl e
0 = No effect.
1 = Enables the corresponding channel.
35.6.4 ADC Channel Disable Register
Register Name: ADC_CHDR
Access Type: Write-only
• CHx: Channel x Disable
0 = No effect.
1 = Disables the corresponding channel.
Warning: If the corresponding channel is disabled during a conversion or if it is disabled then reenabled during a conversion, its
associated data and its corresponding EOC and OVRE flags in ADC_SR are unpredictable.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
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35.6.5 ADC Channel Status Register
Register Name: ADC_CHSR
Access Type: Read-only
• CHx: Channel x Status
0 = Corresponding channel is disabled.
1 = Corresponding channel is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
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35.6.6 ADC Status Register
Register Name: ADC_SR
Access Type: Read-only
• EOCx: End of Conversion x
0 = Corresponding analog channel is disabled, or the conversion is not finished.
1 = Corresponding analog channel is enabled and conversion is complete.
• OVREx: Overrun Error x
0 = No overrun error on the corresponding channel since the last read of ADC_SR.
1 = There has been an overrun error on the corresponding channel since the last read of ADC_SR.
• DRDY: Data Ready
0 = No data has been converted since the last read of ADC_LCDR.
1 = At least one data has been converted and is available in ADC_LCDR.
• GOVRE: General Overrun Error
0 = No General Overrun Error occurred since the last read of ADC_SR.
1 = At least one General Overrun Error has occurred since the last read of ADC_SR.
• ENDRX: End of RX Buffer
0 = The Receive Counter Register has not reached 0 since the last write in ADC_RCR or ADC_RNCR.
1 = The Receive Counter Register has reached 0 since the last write in ADC_RCR or ADC_RNCR.
• RXBUFF: RX Buffer Full
0 = ADC_RCR or ADC_RNCR have a value other than 0.
1 = Both ADC_RCR and ADC_RNCR have a value of 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––RXBUFFENDRXGOVREDRDY
15 14 13 12 11 10 9 8
OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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35.6.7 ADC Last Converted Data Register
Register Name: ADC_LCDR
Access Type: Read-only
• LDATA: Last Data Converted
The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is
completed.
35.6.8 ADC Interrupt Ena bl e Regi st er
Register Name: ADC_IER
Access Type: Write-only
• EOCx: End of Conversion Interrupt Enable x
• OVREx: Overrun Error Interrupt Enable x
• DRDY: Data Ready Interrupt Enable
• GOVRE: General Overrun Error Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– LDATA
76543210
LDATA
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––RXBUFFENDRXGOVREDRDY
15 14 13 12 11 10 9 8
OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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35.6.9 ADC Interrupt Disable Register
Register Name: ADC_IDR
Access Type: Write-only
• EOCx: End of Conversion Interrupt Disable x
• OVREx: Overrun Error Interrupt Disable x
• DRDY: Data Ready Interrupt Disable
• GOVRE: General Overrun Error Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––RXBUFFENDRXGOVREDRDY
15 14 13 12 11 10 9 8
OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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35.6.10 ADC Interrupt Mask Register
Register Name: ADC_IMR
Access Type: Read-only
• EOCx: End of Conversion Interrupt Mask x
• OVREx: Overrun Error Interrupt Mask x
• DRDY: Data Ready Interrupt Mask
• GOVRE: General Overrun Error Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––RXBUFFENDRXGOVREDRDY
15 14 13 12 11 10 9 8
OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0
76543210
EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0
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35.6.11 ADC Channel Data Register
Register Name: ADC_CDRx
Access Type: Read-only
• DATA: Converted Data
The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is
completed. The Convert Data Register (CDR) is only loaded if the corresponding analog channel is enabled.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––– DATA
76543210
DATA
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36. Controller Area Network (CAN)
36.1 Overview
The CAN controller provides all the features required to implement the serial communication protocol CAN defined by
Robert Bosch GmbH, the CAN specification as referred to by ISO/11898A (2.0 Part A and 2.0 Part B) for high speeds
and ISO/11519-2 for low speeds. The CAN Controller is able to handle all types of frames (Data, Remote, Error and
Overload) and achieves a bitrate of 1 Mbit/sec.
CAN controller accesses are made through configuration registers. 8 independent message objects (mailboxes) are
implemented.
Any mailbox can be programmed as a reception buffer block (even non-consecutive buffers). For the reception of defined
messages, one or several message objects can be masked without participating in the buffer feature. An interrupt is
generated when the buffer is full. According to the mailbox configuration, the first message received can be locked in the
CAN controller registers until the application acknowledges it, or this message can be discarded by new received
messages.
Any mailbox can be programmed for transmission. Several transmission mailboxes can be enabled in the same time. A
priority can be defined for each mailbox independently.
An internal 16-bit timer is used to stamp each received and sent message. This timer starts counting as soon as the CAN
controller is enabled. This counter can be reset by the application or automatically after a reception in the last mailbox in
Time Triggered Mode.
The CAN controller offers optimized features to support the Time Triggered Communication (TTC) protocol.
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36.2 Block Diagram
Figure 36-1. CAN Block Diagram
Internal Bus
CAN Interrupt
CANRX
Controller Area Network
PIO CANTX
Error Counter
User Interface
PMC
MCK
Mailbox
Priority
Encoder
MB0
MBx
(x = number of mailboxes - 1)
Control
&
Status
CAN Protocol Controller
MB1
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36.3 Application Block Diagram
Figure 36-2. Application Block Diagram
36.4 I/O Lines Description
36.5 Product Dependencies
36.5.1 I/O Lines
The pins used for interfacing the CAN may be multiplexed with the PIO lines. The programmer must first program the PIO
controller to assign the desired CAN pins to their peripheral function. If I/O lines of the CAN are not used by the
application, they can be used for other purposes by the PIO Controller.
36.5.2 Power Management
The programmer must first enable the CAN clock in the Power Management Controller (PMC) before using the CAN.
A Low-power Mode is defined for the CAN controller: If the application does not require CAN operations, the CAN clock
can be stopped when not needed and be restarted later. Before stopping the clock, the CAN Controller must be in Low-
power Mode to complete the current transfer. After restarting the clock, the application must disable the Low-power Mode
of the CAN controller.
36.5.3 Interrupt
The CAN interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the CAN
interrupt requires the AIC to be programmed first. Note that it is not recommended to use the CAN interrupt line in edge-
sensitive mode.
Software
Software
CAN Controller
Transceiver
ImplementationLayers
CAN-based Application Layer
CAN-based Profiles
CAN Data Link Layer
CAN Physical Layer
Table 36-1. I/O Lines Description
Name Description Type
CANRX CAN Receive Serial Data Input
CANTX CAN Transmi t Serial Data Output
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36.6 CAN Controller Features
36.6.1 CAN Protocol Overview
The Controller Area Network (CAN) is a multi-master serial communication protocol that efficiently supports real-time
control with a very high level of security with bit rates up to 1 Mbit/s.
The CAN protocol supports four different frame types:
Data frames: They carry data from a transmitter node to the receiver nodes. The overall maximum data frame
length is 108 bits for a standard frame and 128 bits for an extended frame.
Remote frames: A destination node can request data from the source by sending a remote frame with an identifier
that matches the identifier of the required data frame. The appropriate data source node then sends a data frame
as a response to this node request.
Error frames: An error frame is generated by any node that detects a bus error.
Overload frames: They provide an extra delay between the preceding and the successive data frames or remote
frames.
The Atmel CAN controller provides the CPU with full functionality of the CAN protocol V2.0 Part A and V2.0 Part B. It
minimizes the CPU load in communication overhead. The Data Link Layer and part of the physical layer are
automatically handled by the CAN controller itself.
The CPU reads or writes data or messages via the CAN controller mailboxes. An identifier is assigned to each mailbox.
The CAN controller encapsulates or decodes data messages to build or to decode bus data frames. Remote frames,
error frames and overload frames are automatically handled by the CAN controller under supervision of the software
application.
36.6.2 Mailbox Organization
The CAN module has 8 buffers, also called channels or mailboxes. An identifier that corresponds to the CAN identifier is
defined for each active mailbox. Message identifiers can match the standard frame identifier or the extended frame
identifier. This identifier is defined for the first time during the CAN initialization, but can be dynamically reconfigured later
so that the mailbox can handle a new message family. Several mailboxes can be configured with the same ID.
Each mailbox can be configured in receive or in transmit mode independently. The mailbox object type is defined in the
MOT field of the CAN_MMRx register.
36.6.2.1 Message Acceptance Procedure
If the MIDE field in the CAN_MIDx register is set, the mailbox can handle the extended format identifier; otherwise, the
mailbox handles the standard format identifier. Once a new message is received, its ID is masked with the CAN_MAMx
value and compared with the CAN_MIDx value. If accepted, the message ID is copied to the CAN_MIDx register.
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Figure 36-3. Message Acceptance Procedure
If a mailbox is dedicated to receiving several messages (a family of messages) with different IDs, the acceptance mask
defined in the CAN_MAMx register must mask the variable part of the ID family. Once a message is received, the
application must decode the masked bits in the CAN_MIDx. To speed up the decoding, masked bits are grouped in the
family ID register (CAN_MFIDx).
For example, if the following message IDs are handled by the same mailbox:
ID0 101000100100010010000100 0 11 00b
ID1 101000100100010010000100 0 11 01b
ID2 101000100100010010000100 0 11 10b
ID3 101000100100010010000100 0 11 11b
ID4 101000100100010010000100 1 11 00b
ID5 101000100100010010000100 1 11 01b
ID6 101000100100010010000100 1 11 10b
ID7 101000100100010010000100 1 11 11b
The CAN_MIDx and CAN_MAMx of Mailbox x must be initialized to the corresponding values:
CAN_MIDx = 001 101000100100010010000100 x 11 xxb
CAN_MAMx = 001 111111111111111111111111 0 11 00b
If Mailbox x receives a message with ID6, then CAN_MIDx and CAN_MFIDx are set:
CAN_MIDx = 001 101000100100010010000100 1 11 10b
CAN_MFIDx = 00000000000000000000000000000110b
If the application associates a handler for each message ID, it may define an array of pointers to functions:
void (*pHandler[8])(void);
When a message is received, the corresponding handler can be invoked using CAN_MFIDx register and there is no need
to check masked bits:
unsigned int MFID0_register;
MFID0_register = Get_CAN_MFID0_Register();
// Get_CAN_MFID0_Register() returns the value of the CAN_MFID0 register
pHandler[MFID0_register]();
36.6.2.2 Receive Mailbox
When the CAN module receives a message, it looks for the first available mailbox with the lowest number and compares
the received message ID with the mailbox ID. If such a mailbox is found, then the message is stored in its data registers.
Depending on the configuration, the mailbox is disabled as long as the message has not been acknowledged by the
application (Receive only), or, if new messages with the same ID are received, then they overwrite the previous ones
(Receive with overwrite).
CAN_MIDx CAN_MAMx Message Received
& &
==
Message Accepted
Message Refused
No
Yes
CAN_MFIDx
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It is also possible to configure a mailbox in Consumer Mode. In this mode, after each transfer request, a remote frame is
automatically sent. The first answer received is stored in the corresponding mailbox data registers.
Several mailboxes can be chained to receive a buffer. They must be configured with the same ID in Receive Mode,
except for the last one, which can be configured in Receive with Overwrite Mode. The last mailbox can be used to detect
a buffer overflow.
36.6.2.3 Transmit Mailbox
When transmitting a message, the message length and data are written to the transmit mailbox with the correct identifier.
For each transmit mailbox, a priority is assigned. The controller automatically sends the message with the highest priority
first (set with the field PRIOR in CAN_MMRx register).
It is also possible to configure a mailbox in Producer Mode. In this mode, when a remote frame is received, the mailbox
data are sent automatically. By enabling this mode, a producer can be done using only one mailbox instead of two: one
to detect the remote frame and one to send the answer.
Mailbox Object Type Description
Receive The first message received is stored in mailbox data registers. Data remain available until the
next transfer request.
Receive with overwrite The last messag e received is stored in mailbox data register. The next message always
overwrites the previous one. The application has to check whether a new message has not
overwritten the current one while read ing the data registers.
Consumer A remote frame is sent by the mailbox. The answer received is stored in mailbox data register.
This extends Receive mailbox features. Data remain available until the next transfer requ est.
Mailbox Object Type Description
Transmit The message stored in th e mailbox data registers will try to win the bus arbitration immediately
or later according to or not the Time Management Unit configuration (see Section 36.6.3).
The application is notified that the message has been sent or aborted.
Producer The message prepared in the mailbox data registers will be sent after receiving the next remote
frame. This extends transmit mail box features.
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36.6.3 Time Management Unit
The CAN Controller integrates a free-running 16-bit internal timer. The counter is driven by the bit clock of the CAN bus
line. It is enabled when the CAN controller is enabled (CANEN set in the CAN_MR register). It is automatically cleared in
the following cases:
after a reset
when the CAN controller is in Low-power Mode is enabled (LPM bit set in the CAN_MR and SLEEP bit set in the
CAN_SR)
after a reset of the CAN controller (CANEN bit in the CAN_MR register)
in Time-triggered Mode, when a message is accepted by the last mailbox (rising edge of the MRDY signal in the
CAN_MSRlast_mailbox_number register).
The application can also reset the internal timer by setting TIMRST in the CAN_TCR register. The current value of the
internal timer is always accessible by reading the CAN_TIM register.
When the timer rolls-over from FFFFh to 0000h, TOVF (Timer Overflow) signal in the CAN_SR register is set. TOVF bit in
the CAN_SR register is cleared by reading the CAN_SR register. Depending on the corresponding interrupt mask in the
CAN_IMR register, an interrupt is generated while TOVF is set.
In a CAN network, some CAN devices may have a larger counter. In this case, the application can also decide to freeze
the internal counter when the timer reaches FFFFh and to wait for a restart condition from another device. This feature is
enabled by setting TIMFRZ in the CAN_MR register. The CAN_TIM register is frozen to the FFFFh value. A clear
condition described above restarts the timer. A timer overflow (TOVF) interrupt is triggered.
To monitor the CAN bus activity, the CAN_TIM register is copied to the CAN _TIMESTP register after each start of frame
or end of frame and a TSTP interrupt is triggered. If TEOF bit in the CAN_MR register is set, the value is captured at each
End Of Frame, else it is captured at each Start Of Frame. Depending on the corresponding mask in the CAN_IMR
register, an interrupt is generated while TSTP is set in the CAN_SR. TSTP bit is cleared by reading the CAN_SR register.
The time management unit can operate in one of the two following modes:
Timestamping mode: The value of the internal timer is captured at each Start Of Frame or each End Of Frame
Time Triggered mode: A mailbox transfer operation is triggered when the internal timer reaches the mailbox
trigger.
Timestamping Mode is enabled by clearing TTM field in the CAN_MR register. Time Triggered Mode is enabled by
setting TTM field in the CAN_MR register.
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36.6.4 CAN 2.0 Standard Features
36.6.4.1 CAN Bit Timing Configuration
All controllers on a CAN bus must have the same bit rate and bit length. At different clock frequencies of the individual
controllers, the bit rate has to be adjusted by the time segments.
The CAN protocol specification partitions the nominal bit time into four different segments:
Figure 36-4. Partition of the CAN Bit Time
TIME QUANTUM
The TIME QUANTUM (TQ) is a fixed unit of time derived from the MCK period. The total number of TIME QUANTA in a
bit time is programmable from 8 to 25.
SYNC SEG: SYNChronization Segment.
This part of the bit time is used to synchronize the various nodes on the bus. An edge is expected to lie within this
segment. It is 1 TQ long.
PROP SEG: PROPagation Segment.
This part of the bit time is used to compensate for the physical delay times within the network. It is twice the sum of the
signal’s propagation time on the bus line, the input comparator delay, and the output driver delay. It is programmable to
be 1,2,..., 8 TQ long.
This parameter is defined in the PROPAG field of the ”CAN Baudrate Register”.
PHASE SEG1, PHASE SEG2: PHASE Segment 1 and 2.
The Phase-Buffer-Segments are used to compensate for edge phase errors. These segments can be lengthened
(PHASE SEG1) or shortened (PHASE SEG2) by resynchronization.
Phase Segment 1 is programmable to be 1,2,..., 8 TQ long.
Phase Segment 2 length has to be at least as long as the Information Processing Time (IPT) and may not be more than
the length of Phase Segment 1.
These parameters are defined in the PHASE1 and PHASE2 fields of the ”CAN Baudrate Register”.
INFORMATION PROCESSING TIME:
The Information Processing Time (IPT) is the time required for the logic to determine the bit level of a sampled bit. The
IPT begins at the sample point, is measured in TQ and is fixed at 2 TQ for the Atmel CAN. Since Phase Segment 2
also begins at the sample point and is the last segment in the bit time, PHASE SEG2 shall not be less than the IPT.
SAMPLE POINT:
The SAMPLE POINT is the point in time at which the bus level is read and interpreted as the value of th at respective bit.
Its location is at the end of PHASE_SEG1.
SJW: ReSynchronization Jump Width.
The ReSynchronization Jump Width defines the limit to the amount of lengthening or shortening of the Phase Segments.
SJW is programmable to be the minimum of PHASE SEG1 and 4 TQ.
If the SMP field in the CAN_BR register is set, then the incoming bit stream is sampled three times with a period of half a
CAN clock period, centered on sample point.
SYNC_SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
NOMINAL BIT TIME
Sample Point
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In the CAN controller, the length of a bit on the CAN bus is determined by the parameters (BRP, PROPAG, PHASE1 and
PHASE2).
The time quantum is calculated as follows:
Note: The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
To compensate for phase shifts between clock oscillators of different controllers on the bus, the CAN controller must
resynchronize on any relevant signal edge of the current transmission. The resynchronization shortens or lengthens the
bit time so that the position of the sample point is shifted with regard to the detected edge. The resynchronization jump
width (SJW) defines the maximum of time by which a bit period may be shortened or lengthened by resynchronization.
Figure 36-5. CAN Bit Timing
Example of bit timing determination for CAN baudrate of 500 Kbit/s:
MCK = 48MHz
CAN baudrate= 500kbit/s => bit time= 2us
Delay of the bus driver: 50 ns
Delay of the receiver: 30ns
Delay of the bus line (20m): 110ns
The total number of time quanta in a bit time must be comprised between 8 and
25. If we fix the bit time to 16 time quanta:
Tcsc = 1 time quanta = bit time / 16 = 125 ns
=> BRP = (Tcsc x MCK) - 1 = 5
The propagation segment time is equal to twice the sum of the signal’s
propagation time on the bus line, the receiver delay and the output driver
delay:
Tprs = 2 * (50+30+110) ns = 380 ns = 3 Tcsc
=> PROPAG = Tprs/Tcsc - 1 = 2
The remaining time for the two phase segments is:
Tphs1 + Tphs2 = bit time - Tcsc - Tprs = (16 - 1 - 3)Tcsc
tBIT tCSC tPRS tPHS1 tPHS2
++ +=
tCSC BRP 1+()MCK⁄=
tPRS tCSC PROPAG 1+()×=
tPHS1 tCSC PHASE1 1+()×=
tPHS2 tCSC PHASE2 1+()×=
tSJW tCSC SJW 1+()×=
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
NOMINAL BIT TIME
Sample Point Transmission Point
MCK
CAN Clock
t
CSC
t
PRS
t
PHS1
t
PHS2
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Tphs1 + Tphs2 = 12 Tcsc
Because this number is even, we choose Tphs2 = Tphs1 (else we would choose Tphs2
= Tphs1 + Tcsc)
Tphs1 = Tphs2 = (12/2) Tcsc = 6 Tcsc
=> PHASE1 = PHASE2 = Tphs1/Tcsc - 1 = 5
The resynchronization jump width must be comprised between 1 Tcsc and the
minimum of 4 Tcsc and Tphs1. We choose its maximum value:
Tsjw = Min(4 Tcsc,Tphs1) = 4 Tcsc
=> SJW = Tsjw/Tcsc - 1 = 3
Finally: CAN_BR = 0x00053255
36.6.4.2 CAN Bus Synchronization
Two types of synchronization are distinguished: “hard synchronization” at the start of a frame and “resynchronization”
inside a frame. After a hard synchronization, the bit time is restarted with the end of the SYNC_SEG segment, regardless
of the phase error. Resynchronization causes a reduction or increase in the bit time so that the position of the sample
point is shifted with respect to the detected edge.
The effect of resynchronization is the same as that of hard synchronization when the magnitude of the phase error of the
edge causing the resynchronization is less than or equal to the programmed value of the resynchronization jump width
(tSJW).
When the magnitude of the phase error is larger than the resynchronization jump width and
the phase error is positive, then PHASE_SEG1 is lengthened by an amount equal to the resynchronization jump
width.
the phase error is negative, then PHASE_SEG2 is shortened by an amount equal to the resynchronization jump
width.
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Figure 36-6. CAN Resynchronization
36.6.4.3 Autobaud Mode
The autobaud feature is enabled by setting the ABM field in the CAN_MR register. In this mode, the CAN controller is
only listening to the line without acknowledging the received messages. It can not send any message. The errors flags
are updated. The bit timing can be adjusted until no error occurs (good configuration found). In this mode, the error
counters are frozen. To go back to the standard mode, the ABM bit must be cleared in the CAN_MR register.
36.6.4.4 Error Detection
There are five different error types that are not mutually exclusive. Each error concerns only specific fields of the CAN
data frame (refer to the Bosch CAN specification for their correspondence):
CRC error (CERR bit in the CAN_SR register): With the CRC, the transmitter calculates a checksum for the CRC
bit sequence from the Start of Frame bit until the end of the Data Field. This CRC sequence is transmitted in the
CRC field of the Data or Remote Frame.
Bit-stuffing error (SERR bit in the CAN_SR register): If a node detect s a sixth consecutive equal bit level during the
bit-stuffing area of a frame, it generates an Error Frame starting with the next bit-time.
Bit error (BERR bit in CAN_SR register): A bit error occurs if a transmitter sends a dominant bit but detects a
recessive bit on the bus line, or if it sends a recessive bit but detects a dominant bit on the bus line. An error frame
is generated and starts with the next bit time.
Form Error (FERR bit in the CAN_SR register): If a transmitter detects a dominant bit in one of the fix-formatted
segments CRC Delimiter, ACK Delimiter or End of Frame, a form error has occurred and an error frame is
generated.
Acknowledgment error (AERR bit in the CAN_SR register): The transmitter checks the Acknowledge Slot, which is
transmitted by the transmitting node as a recessive bit, contains a dominant bit. If this is the case, at least one
other node has received the frame correctly. If not, an Acknowledge Error has occurred and the transmitter will
start in the next bit-time an Error Frame transmission.
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
SYNC_
SEG PROP_SEG PHASE_SEG1 PHASE_SEG2
Phase error Phase error (max Tsjw)
SYNC_
SEG
SYNC_
SEG
SYNC_
SEG PROP_SEG PHASE_SEG1
PHASE_SEG2 SYNC_
SEG
PHASE_SEG2
SYNC_
SEG PROP_SEG PHASE_SEG1
PHASE_
SEG2 SYNC_
SEG
PHASE_SEG2
Phase error
Nominal
Sample point Sample point
after resynchronization
Nominal
Sample point
Sample point
after resynchronization
THE PHASE ERROR IS POSITIVE
(the transmitter is slower than the receiver)
Received
data bit
Received
data bit
Nominal bit time
(before resynchronization)
Bit time with
resynchronization
Bit time with
resynchronization
Phase error (max Tsjw)
Nominal bit time
(before resynchronization)
THE PHASE ERROR IS NEGATIVE
(the transmitter is faster than the receiver)
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36.6.4.5 Fault Confinement
To distinguish between temporary and permanent failures, every CAN controller has two error counters: REC (Receive
Error Counter) and TEC (Transmit Error Counter). The two counters are incremented upon detected errors and are
decremented upon correct transmissions or receptions, respectively. Depending on the counter values, the state of the
node changes: the initial state of the CAN controller is Error Active, meaning that the controller can send Error Active
flags. The controller changes to the Error Passive state if there is an accumulation of errors. If the CAN controller fails or
if there is an extreme accumulation of errors, there is a state transition to Bus Off.
Figure 36-7. Line Error Mode
An error active unit takes part in bus communication and sends an active error frame when the CAN controller detects an
error.
An error passive unit cannot send an active error frame. It takes part in bus communication, but when an error is
detected, a passive error frame is sent. Also, after a transmission, an error passive unit waits before initiating further
transmission.
A bus off unit is not allowed to have any influence on the bus.
For fault confinement, two errors counters (TEC and REC) are implemented. These counters are accessible via the
CAN_ECR register. The state of the CAN controller is automatically updated according to these counter values. If the
CAN controller is in Error Active state, then the ERRA bit is set in the CAN_SR register. The corresponding interrupt is
pending while the interrupt is not masked in the CAN_IMR register. If the CAN controller is in Error Passive Mode, then
the ERRP bit is set in the CAN_SR register and an interrupt remains pending while the ERRP bit is set in the CAN_IMR
register. If the CAN is in Bus Off Mode, then the BOFF bit is set in the CAN_SR register. As for ERRP and ERRA, an
interrupt is pending while the BOFF bit is set in the CAN_IMR register.
When one of the error counters values exceeds 96, an increased error rate is indicated to the controller through the
WARN bit in CAN_SR register, but the node remains error active. The corresponding interrupt is pending while the
interrupt is set in the CAN_IMR register.
Refer to the Bosch CAN specification v2.0 for details on fault confinement.
36.6.4.6 Error Interrupt Handler
WARN, BOFF, ERRA and ERRP (CAN_SR) represent the current status of the CAN bus and are not latched. They
reflect the current TEC and REC (CAN_ECR) values as described in Section 36.6.4.5 “Fault Confinement” on page 492.
Based on that, if these bits are used as an interrupt, the user can enter into an interrupt and not see the corresponding
status register if the TEC and REC counter have changed their state. When entering Bus Off Mode, the only way to exit
from this state is 128 occurrences of 11 consecutive recessive bits or a CAN controller reset.
In Error Active Mode, the user reads:
ERRA =1
ERROR
ACTIVE
ERROR
PASSIVE BUS OFF
TEC > 255
Init
TEC < 127
and
REC < 127
TEC >127
or
REC > 127
128 occurences of 11 consecutive recessive bits
or
CAN controller reset
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ERRP = 0
BOFF = 0
In Error Passive Mode, the user reads:
ERRA = 0
ERRP =1
BOFF = 0
In Bus Off Mode, the user reads:
ERRA = 0
ERRP =1
BOFF =1
The CAN interrupt handler should do the following:
Only enable one error mode interrupt at a time.
Look at and check the REC and TEC values in the interrupt handler to determine the current state.
36.6.4.7 Overload
The overload frame is provided to request a delay of the next data or remote frame by the receiver node (“Request
overload frame”) or to signal certain error conditions (“Reactive overload frame”) related to the intermission field
respectively.
Reactive overload frames are transmitted after detection of the following error conditions:
Detection of a dominant bit during the first two bits of the intermission field
Detection of a dominant bit in the last bit of EOF by a receiver, or detection of a dominant bit by a receiver or a
transmitter at the last bit of an error or overload frame delimiter
The CAN controller can generate a request overload frame automatically after each message sent to one of the CAN
controller mailboxes. This feature is enabled by setting the OVL bit in the CAN_MR register.
Reactive overload frames are automatically handled by the CAN controlle r even if the OVL bit in the CAN_MR register is
not set. An overload flag is generated in the same way as an error flag, but error counters do not increment.
36.6.5 Low-power Mode
In Low-power Mode, the CAN controller cannot send or receive messages. All mailboxes are inactive.
In Low-power Mode, the SLEEP signal in the CAN_SR register is set; otherwise, the WAKEUP signal in the CAN_SR
register is set. These two fields are exclusive except after a CAN controller reset (WAKEUP and SLEEP are stuck at 0
after a reset). After power-up reset, the Low-power Mode is disabled and the WAKEUP bit is set in the CAN_SR register
only after detection of 11 consecutive recessive bits on the bus.
36.6.5.1 Enabling Low-power Mode
A software application can enable Low-power Mode by setting the LPM bit in the CAN_MR global register. The CAN
controller enters Low-power Mode once all pending transmit messages are sent.
When the CAN controller enters Low-power Mode, the SLEEP signal in the CAN_SR register is set. Depending on the
corresponding mask in the CAN_IMR register, an interrupt is generated while SLEEP is set.
The SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. The WAKEUP signal is
automatically cleared once SLEEP is set.
Reception is disabled while the SLEEP signal is set to one in the CAN_SR register. It is important to note that those
messages with higher priority than the last message transmitted can be received between the LPM command and entry
in Low-power Mode.
Once in Low-power Mode, the CAN controller clock can be switched off by programming the chip’s Power Management
Controller (PMC). The CAN controller drains only the static current.
Error counters are disabled while the SLEEP signal is set to one.
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Thus, to enter Low-power Mode, the software application must:
Set LPM field in the CAN_MR register
Wait for SLEEP signal rising
Now the CAN Controller clock can be disabled. This is done by programming the Power Management Controller (PMC).
Figure 36-8. Enabling Low-power Mode
36.6.5.2 Disabling Low-power Mode
The CAN controller can be awake after detecting a CAN bus activity. Bus activity detection is done by an external module
that may be embedded in the chip. When it is notified of a CAN bus activity, the software application disables Low-power
Mode by programming the CAN controller.
To disable Low-power Mode, the software application must:
Enable the CAN Controller clock. This is done by programming the Power Management Controller (PMC).
Clear the LPM field in the CAN_MR register
The CAN controller synchronizes itself with the bus activity by checking for eleven consecutive “recessive” bits. Once
synchronized, the WAKEUP signal in the CAN_SR register is set.
Depending on the corresponding mask in the CAN_IMR register, an interrupt is generated while WAKEUP is set. The
SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. WAKEUP signal is automatically
cleared once SLEEP is set.
If no message is being sent on the bus, then the CAN controller is able to send a message eleven bit times after disabling
Low-power Mode.
If there is bus activity when Low-power mode is disabled, the CAN controller is synchronized with the bus activity in the
next interframe. The previous message is lost (see Figure 36-9).
SLEEP
(CAN_SR)
MRDY
(CAN_MSR1)
LPM
(CAN_MR)
LPEN= 1
CAN BUS
MRDY
(CAN_MSR3)
Mailbox 1 Mailbox 3
Arbitration lost
WAKEUP
(CAN_SR)
0x0CAN_TIM
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Figure 36-9. Disabling Low-power Mode
36.7 Functional Description
36.7.1 CAN Controller Initialization
After power-up reset, the CAN controller is disabled. The CAN controller clock must be activated by the Power
Management Controller (PMC) and the CAN controller interrupt line must be enabled by the interrupt controller (AIC).
The CAN controller must be initialized with the CAN network parameters. The CAN_BR register defines the sampling
point in the bit time period. CAN_BR must be set before the CAN controller is enabled by setting the CANEN field in the
CAN_MR register.
The CAN controller is enabled by setting the CANEN flag in the CAN_MR register. At this stage, the internal CAN
controller state machine is reset, error counters are reset to 0, error flags are reset to 0.
Once the CAN controller is enabled, bus synchronization is done automatically by scanning eleven recessive bits. The
WAKEUP bit in the CAN_SR register is automatically set to 1 when the CAN controller is synchronized (WAKEUP and
SLEEP are stuck at 0 after a reset).
The CAN controller can start listening to the network in Autobaud Mode. In this case, the error counters are locked and a
mailbox may be configured in Receive Mode. By scanning error flags, the CAN_BR register values synchronized with the
network. Once no error has been detected, the application disables the Autobaud Mode, clearing the ABM field in the
CAN_MR register.
SLEEP
(CAN_SR)
MRDY
(CAN_MSRx)
LPM
(CAN_MR)
CAN BUS
Bus Activity Detected
Message x
Interframe synchronization
WAKEUP
(CAN_SR)
Message lost
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Figure 36-10. Possible Initialization Procedure
36.7.2 CAN Controller Interrupt Handling
There are two different types of interrupts. One type of interrupt is a message-object related interrupt, the other is a
system interrupt that handles errors or system-related interrupt sources.
All interrupt sources can be masked by writing the corresponding field in the CAN_IDR register. They can be unmasked
by writing to the CAN_IER register. After a power-up reset, all interrupt sources are disabled (masked). The current mask
status can be checked by reading the CAN_IMR register.
The CAN_SR register gives all interrupt source states.
The following events may initiate one of the two interrupts:
Message object interrupt
Data registers in the mailbox object are available to the application. In Receive Mode, a new message was
received. In Transmit Mode, a message was transmitted successfully.
A sent transmission was aborted.
System interrupts
Bus off interrupt: The CAN module enters the bus off state.
Error passive interrupt: The CAN module enters Error Passive Mode.
Error Active Mode: The CAN module is neither in Error Passive Mode nor in Bus Off mode.
Warn Limit interrupt: The CAN module is in Error-active Mode, but at least one of its error counter value
exceeds 96.
Wake-up interrupt: This interrupt is generated after a wake-up and a bus synchronization.
Sleep interrupt: This interrupt is generated after a Low-power Mode enable once all pending messages in
transmission have been sent.
Internal timer counter overflow interrupt: This interrupt is generated when the internal timer rolls over.
Errors ?
No
Yes
(ABM == 1 and CANEN == 1)
CANEN = 1 (ABM == 0)
ABM = 0 and CANEN = 0
(CAN_SR or CAN_MSRx)
Change CAN_BR value
End of Initialization
Configure a Mailbox in Reception Mode
Enable CAN Controller Interrupt Line
Enable CAN Controller Clock
(AIC)
(PMC)
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T imestamp interrupt: This interrupt is generated after the reception or the transmission of a start of frame or
an end of frame. The value of the internal counter is copied in the CAN_TIMESTP register.
All interrupts are cleared by clearing the interrupt source except for the internal timer counter overflow interrupt and the
timestamp interrupt. These interrupts are cleared by reading the CAN_SR register.
36.7.3 CAN Controller Message Handling
36.7.3.1 Receive Handling
Two modes are available to configure a mailbox to receive messages. In Receive Mode, the first message received is
stored in the mailbox data register. In Receive with Overwrite Mode, the last message received is stored in the mailbox.
36.7.3.2 Simple Receive Mailbox
A mailbox is in Receive Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and
Message Acceptance Mask must be set before the Receive Mode is enabled.
After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first message
is received. When the first message has been accepted by the mailbox, the MRDY flag is set. An interrupt is pending for
the mailbox while the MRDY flag is set. This interrupt can be masked depending on the mailbox flag in the CAN_IMR
global register.
Message data are stored in the mailbox data register until the software application notifies that data processing has
ended. This is done by asking for a new transfer command, setting the MTCR flag in the CAN_MCRx register. This
automatically clears the MRDY signal.
The MMI flag in the CAN_MSRx register notifies the software that a message has been lost by the mailbox. This flag is
set when messages are received while MRDY is set in the CAN_MSRx register. This flag is cleared by reading the
CAN_MSRs register. A receive mailbox prevents from overwriting the first message by new ones while MRDY flag is set
in the CAN_MSRx register. See Figure 36-11.
Figure 36-11. Receiv e Mail box
Note: In the case of ARM architecture, CAN_MSRx, CAN_MDLx, CAN_MDHx can be read using an optimized ldm assem-
bler instruction.
36.7.3.3 Receive with Overwrite Mailbox
A mailbox is in Receive with Overwrite Mode once the MOT field in the CAN_MMRx register has been configured.
Message ID and Message Acceptance masks must be set before Receive Mode is enabled.
Message 1 Message 2 lost Message 3
Message 3
Message 1
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS
(CAN_MDLx
CAN_MDHx)
MTCR
(CAN_MCRx)
Message ID = CAN_MIDx
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After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first message
is received. When the first message has been accepted by the mailbox, the MRDY flag is set. An interrupt is pending for
the mailbox while the MRDY flag is set. This interrupt is masked depending on the mailbox flag in the CAN_IMR global
register.
If a new message is received while the MRDY flag is set, this new message is stored in the mailbox data register,
overwriting the previous message. The MMI flag in the CAN_MSRx register notifies the software that a message has
been dropped by the mailbox. This flag is cleared when reading the CAN_MSRx register.
The CAN controller may store a new message in the CAN data registers while the application re ads them. To check that
CAN_MDHx and CAN_MDLx do not belong to different messages, the application must check the MMI field in the
CAN_MSRx register before and after reading CAN_MDHx and CAN_MDLx. If the MMI flag is set again after the data
registers have been read, the software application has to re-read CAN_MDHx and CAN_MDLx (see Figure 36-12).
Figure 36-12. Receive with Overwrite Mailbox
36.7.3.4 Chaining Mailboxes
Several mailboxes may be used to receive a buffer split into several messages with the same ID. In this case, the
mailbox with the lowest number is serviced first. In the receive and receive with overwrite modes, the field PRIOR in the
CAN_MMRx register has no effect. If Mailbox 0 and Mailbox 5 accept messages with the same ID, the first message is
received by Mailbox 0 and the second message is received by Mailbox 5. Mailbox 0 must be configured in Receive Mode
(i.e., the first message received is considered) and Mailbox 5 must be configured in Receive with Overwrite Mode.
Mailbox 0 cannot be configured in Receive with Overwrite Mode; otherwise, all messages are accepted by this mailbox
and Mailbox 5 is never serviced.
If several mailboxes are chained to receive a buffer split into several messages, all mailboxes except the last one (with
the highest number) must be configured in Receive Mode. The first message received is handled by the first mailbox, the
second one is refused by the first mailbox and accepted by the second mailbox, the last message is accepted by the last
mailbox and refused by previous ones (see Figure 36-13).
Message 1 Message 2 Message 3
Message 3 Message 1
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS
(CAN_MDLx
CAN_MDHx)
MTCR
(CAN_MCRx)
Message ID = CAN_MIDx
Message 4
Message 2 Message 4
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Figure 36-13. Chaining Three Mailboxes to Receive a Buffer Split into Three Messages
If the number of mailboxes is not sufficient (the MMI flag of the last mailbox raises), the user must read each data
received on the last mailbox in order to retrieve all the messages of the buffer split (see Figure 36-14).
Figure 36-14. Chaining Three Mailboxes to Receive a Buffer Split into Fo ur Messages
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS Message s1
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Writing MBx MBy MBz in CAN_TCR
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
MMI
(CAN_MSRy)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRz)
MRDY
(CAN_MSRz)
Message s2 Message s3
Buffer split in 3 messages
MMI
(CAN_MSRx)
MRDY
(CAN_MSRx)
CAN BUS Message s1
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Writing MBx MBy MBz in CAN_TCR
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
MMI
(CAN_MSRy)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRz)
MRDY
(CAN_MSRz)
Message s2 Message s3
Buffer split in 4 messages
Message s4
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36.7.3.5 Transmission Handling
A mailbox is in Transmit Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and
Message Acceptance mask must be set before Receive Mode is enabled.
After Transmit Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set until the first command is
sent. When the MRDY flag is set, the software application can prepare a message to be sent by writing to the CAN_MDx
registers. The message is sent once the software asks for a transfer command setting the MTCR bit and the message
data length in the CAN_MCRx register.
The MRDY flag remains at zero as long as the message has not been sent or aborted. It is important to note that no
access to the mailbox data register is allowed while the MRDY flag is cleared. An interrupt is pending for the mailbox
while the MRDY flag is set. This interrupt can be masked depending on the mailbox flag in the CAN_IMR global register.
It is also possible to send a remote frame setting the MRTR bit instead of setting the MDLC field. The answer to the
remote frame is handled by another reception mailbox. In this case, the device acts as a consumer but with the help of
two mailboxes. It is possible to handle the remote frame emission and the answer reception using only one mailbox
configured in Consumer Mode. Refer to the section “Remote Frame Handling” on page 501.
Several messages can try to win the bus arbitration in the same time. The message with the highest priority is sent first.
Several transfer request commands can be generated at the same time by setting MBx bits in the CAN_TCR register.
The priority is set in the PRIOR field of the CAN_MMRx register. Priority 0 is the highest priority, priority 15 is the lowest
priority. Thus it is possible to use a part of the message ID to set the PRIOR field. If two mailboxes have the same
priority, the message of the mailbox with the lowest number is sent first. Thus if mailbox 0 and mailbox 5 have the same
priority and have a message to send at the same time, then the message of the mailbox 0 is sent first.
Setting the MACR bit in the CAN_MCRx register aborts the transmission. Transmission for several mailboxes can be
aborted by writing MBx fields in the CAN_MACR register. If the message is being sent when the abort command is set,
then the application is notified by the MRDY bit set and not the MABT in the CAN_MSRx register. Otherwise, if the
message has not been sent, then the MRDY and the MABT are set in the CAN_MSR register.
When the bus arbitration is lost by a mailbox message, the CAN controller tries to win the next bus arbitration with the
same message if this one still has the highest priority. Messages to be sent are re-tried automatically until they win the
bus arbitration. This feature can be disabled by setting the bit DRPT in the CAN_MR register. In this case if the message
was not sent the first time it was transmitted to the CAN transceiver, it is automatically aborted. The MABT flag is set in
the CAN_MSRx register until the next transfer command.
Figure 36-15 shows three MBx message attempts being made (MRDY of MBx set to 0).
The first MBx message is sent, the second is aborted and the last one is trying to be aborted but too late because it has
already been transmitted to the CAN transceiver.
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Figure 36-15. Transmitting Messages
36.7.3.6 Remote Frame Handling
Producer/consumer model is an efficient means of handling broadcasted messages. The push model allows a producer
to broadcast messages; the pull model allows a customer to ask for messages.
Figure 36-16. Producer / Consume r Mode l
In Pull Mode, a consumer transmits a remote frame to the producer. When the producer receives a remote frame, it
sends the answer accepted by one or many consumers. Using transmit and receive mailboxes, a consumer must
dedicate two mailboxes, one in Transmit Mode to send remote frames, and at least one in Receive Mode to capture the
producer’s answer. The same structure is applicable to a producer: one reception mailbox is required to get the remote
frame and one transmit mailbox to answer.
Mailboxes can be configured in Producer or Consumer Mode. A lonely mailbox can handle the remote frame and the
answer. With 8 mailboxes, the CAN controller can handle 8 independent producers/consumers.
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUS MBx message
Reading CAN_MSRx
Writing CAN_MDHx &
CAN_MDLx
MBx message
MACR
(CAN_MCRx) Abort MBx message Try to Abort MBx message
MABT
(CAN_MSRx)
CAN Data Frame
CAN Remote Frame
CAN Data Frame
Indication(s)
Request
Request(s)
Indications
Response
Confirmation(s)
PUSH MODEL
PULL MODEL
Producer
Producer
Consumer
Consumer
502
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.7.3.7 Producer Configuration
A mailbox is in Producer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and
Message Acceptance masks must be set before Receive Mode is enabled.
After Producer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set until the first transfer
command. The software application prepares data to be sent by writing to the CAN_MDHx and the CAN_MDLx registers,
then by setting the MTCR bit in the CAN_MCRx register. Data is sent after the reception of a remote frame as soon as it
wins the bus arbitration.
The MRDY flag remains at zero as long as the message has not been sent or aborted. No access to the mailbox data
register can be done while MRDY flag is cleared. An interrupt is pending for the mailbox while the MRDY flag is set. This
interrupt can be masked according to the mailbox flag in the CAN_IMR global register.
If a remote frame is received while no data are ready to be sent (signal MRDY set in the CAN_MSRx register), then the
MMI signal is set in the CAN_MSRx register. This bit is cleared by reading the CAN_MSRx register.
The MRTR field in the CAN_MSRx register has no meaning. This field is used only when using Receive and Receive with
Overwrite modes.
After a remote frame has been received, the mailbox functions like a transmit mailbox. The message with the highest
priority is sent first. The transmitted message may be aborted by setting the MACR bit in the CAN_MCR register. Please
refer to the section “Transmission Handling” on page 500.
Figure 36-17. Producer Handling
36.7.3.8 Consumer Configuration
A mailbox is in Consumer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and
Message Acceptance masks must be set before Receive Mode is enabled.
After Consumer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically cleared until the first transfer
request command. The software application sends a remote frame by setting the MTCR b it in the CAN_MCRx register or
the MBx bit in the global CAN_TCR register. The application is notified of the answer by the MRDY flag set in the
CAN_MSRx register. The application can read the data contents in the CAN_MDHx and CAN_MDLx registers. An
interrupt is pending for the mailbox while the MRDY flag is set. This interrupt can be masked according to the mailbox
flag in the CAN_IMR global register.
The MRTR bit in the CAN_MCRx register has no effect. This field is used only when using Transmit Mode.
After a remote frame has been sent, the consumer mailbox functions as a reception mailbox. The first message received
is stored in the mailbox data registers. If other messages intended for this mailbox have been sent while the MRDY flag
is set in the CAN_MSRx register, they will be lost. The application is notified by reading the MMI field in the CAN_MSRx
register. The read operation automatically clears the MMI flag.
If several messages are answered by the Producer, the CAN controller may have one mailbox in consumer
configuration, zero or several mailboxes in Receive Mode and one mailbox in Receive with Overwrite Mode. In this case,
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUS Remote Frame Message 1
Message 1
Message 2
(CAN_MDLx
CAN_MDHx)
MMI
(CAN_MSRx)
Remote Frame Remote Frame
Message 2
Reading CAN_MSRx
503
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
the consumer mailbox must have a lower number than the Receive with Overwrite mailbox. The transfer command can
be triggered for all mailboxes at the same time by setting several MBx fields in the CAN_TCR register.
Figure 36-18. Consumer Handling
36.7.4 CAN Controller Timing Modes
Using the free running 16-bit internal timer, the CAN controller can be set in one of the two following timing modes:
Timestamping Mode: The value of the internal timer is captured at each Start Of Frame or each End Of Frame.
Time Triggered Mode: The mailbox transfer operation is triggered when the internal timer reaches the mailbox
trigger.
Timestamping Mode is enabled by clearing the TTM bit in the CAN_MR register. Time Triggered Mode is enabled by
setting the TTM bit in the CAN_MR register.
36.7.4.1 Timestamping Mode
Each mailbox has its own timestamp value. Each time a message is sent or received by a mailbox, the 16-bit value
MTIMESTAMP of the CAN_TIMESTP register is transferred to the LSB bits of the CAN_MSRx register. The value read in
the CAN_MSRx register corresponds to the internal timer value at the Start Of Frame or the End Of Frame of the
message handled by the mailbox.
Figure 36-19. Mailbox Timestamp
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUS Remote Frame Message x
Message y
Message y
(CAN_MDLx
CAN_MDHx)
MMI
(CAN_MSRx)
Remote Frame
Message x
TEOF
(CAN_MR)
MTIMESTAMP
(CAN_MSRx)
CAN_TIM
CAN BUS
MTIMESTAMP
(CAN_MSRy)
Message 1 Message 2
Start of Frame
TIMESTAMP
(CAN_TSTP)
End of Frame
Timestamp 1
Timestamp 1
Timestamp 2
Timestamp 2
504
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.7.4.2 Time Triggered Mode
In Time Triggered Mode, basic cycles can be split into several time windows. A basic cycle starts with a reference
message. Each time a window is defined from the reference message, a transmit operation should occur within a pre-
defined time window. A mailbox must not win the arbitration in a previous time window, and it must not be retried if the
arbitration is lost in the time window.
Figure 36-20. Time Triggered Principle
Time Trigger Mode is enabled by setting the TTM field in the CAN_MR register. In Time Triggered Mode, as in
Timestamp Mode, the CAN_TIMESTP field captures the values of the internal counter, but the MTIMESTAMP fields in
the CAN_MSRx registers are not active and are read at 0.
36.7.4.3 Synchronization by a Reference Message
In Time Triggered Mode, the internal timer counter is automatically reset when a new message is received in the last
mailbox. This reset occurs after the reception of the End Of Frame on the rising edge of the MRDY signal in the
CAN_MSRx register. This allows synchronization of the internal timer counter with the reception of a reference message
and the start a new time window.
36.7.4.4 Transmitting within a Time Window
A time mark is defined for each mailbox. It is defined in the 16-bit MTIMEMARK field of the CAN_MMRx register. At each
internal timer clock cycle, the value of the CAN_TIM is compared with each mailbox time mark. When the internal timer
counter reaches the MTIMEMARK value, an internal timer event for the mailbox is generated for the mailbox.
In Time Triggered Mode, transmit operations are delayed until the internal timer event for the mailbox. The application
prepares a message to be sent by setting the MTCR in the CAN_MCRx register. The message is not sent until the
CAN_TIM value is less than the MTIMEMARK value defined in the CAN_MMRx register.
If the transmit operation is failed, i.e., the message loses the bus arbitration and the next transmit attempt is delayed until
the next internal time trigger event. This prevents overlapping the next time window, but the message is still pending and
is retried in the next time window when CAN_TIM value equals the MTIMEMARK value. It is also possible to prevent a
retry by setting the DRPT field in the CAN_MR register.
36.7.4.5 Freezing the Internal Timer Counter
The internal counter can be frozen by setting TIMFRZ in the CAN_MR register. This prevents an unexpected roll-over
when the counter reaches FFFFh. When this occurs, it automatically freezes until a new reset is issued, either due to a
message received in the last mailbox or any other reset counter operations. The TOVF bit in the CAN_SR register is set
when the counter is frozen. The TOVF bit in the CAN_SR register is cleared by reading the CAN_SR register. Depending
on the corresponding interrupt mask in the CAN_IMR register, an interrupt is generated when TOVF is set.
Reference
Message Reference
Message
Global Time
Time Cycle
Time Windows for Messages
505
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 36-21. Time Triggered Operations
MRDY
(CAN_MSRlast_mailbox_number)
CAN_TIM
CAN BUS
MRDY
(CAN_MSRx)
End of Frame
Timer Event x MTIMEMARKx == CAN_TIM
Timer Event y
MRDY
(CAN_MSRy)
MTIMEMARKy == CAN_TIM
Cleared by software
Internal Counter Reset
Message x
Arbitration Lost Message y
Arbitration Win
Reference
Message Message y
MRDY
(CAN_MSRlast_mailbox_number)
CAN_TIM
CAN BUS
MRDY
(CAN_MSRx)
End of Frame
Timer Event x MTIMEMARKx == CAN_TIM
Cleared by software
Internal Counter Reset
Message x
Arbitration Win
Reference
Message Message x
Basic Cycle
Time Window
Basic Cycle
Time Window
506
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8 Controller Area Network (CAN) User Interface
Table 36-2. Regist er Mapping
Offset Register Name Access Reset
0x0000 Mode Register CAN_MR Read-write 0x0
0x0004 Interrupt Enable Register CAN_IER Write-only -
0x0008 Interrupt Disable Register CAN_IDR Write-only -
0x000C Interrupt Mask Register CAN_IMR Read-only 0x0
0x0010 Status Register CAN_SR Read-only 0x0
0x0014 Baudrate Register CAN_BR Read-write 0x0
0x0018 Timer Register CAN_TIM Read-only 0x0
0x001C Timestamp Register CAN_TIMESTP Read-only 0x0
0x0020 Error Counter Register CAN_ECR Read-only 0x0
0x0024 Transfer Command Register CAN_TCR Write-only -
0x0028 Abort Command Register CAN_ACR Write-only -
0x0100 - 0x01FC Reserved – – –
0x0200 Mailbox 0 Mode Register CAN_MMR0 Read-write 0x0
0x0204 Mailbox 0 Acce ptance Mask Register CAN_ MAM0 Read-write 0x0
0x0208 Mailbox 0 ID Reg ister CAN_MID0 Read-write 0x0
0x020C Mailbox 0 Family ID Register CAN_MFID0 Read-only 0x0
0x0210 Mailbox 0 Status Register CAN _MSR0 Read-only 0x0
0x0214 Mailbox 0 Data Low Register CAN_MDL0 Read-write 0x0
0x0218 Mailbox 0 Data High Register CAN_MDH0 Read-write 0x0
0x021C Mailbox 0 Control Register CAN_MCR0 Write-only -
0x0220 Mailbox 1 Mode Register CAN_MMR1 Read-write 0x0
0x0224 Mailbox 1 Acce ptance Mask Register CAN_ MAM1 Read-write 0x0
0x0228 Mailbox 1 ID register CAN_MID1 Read-write 0x0
0x022C Mailbox 1 Family ID Register CAN_MFID1 Read-only 0x0
0x0230 Mailbox 1 Status Register CAN _MSR1 Read-only 0x0
0x0234 Mailbox 1 Data Low Register CAN_MDL1 Read-write 0x0
0x0238 Mailbox 1 Data High Register CAN_MDH1 Read-write 0x0
0x023C Mailbox 1 Control Register CAN_MCR1 Write-only -
... ... ... ... -
507
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.1 CAN Mode Register
Name: CAN_MR
Access Type: Read-write
• CANEN: CAN Controller Enable
0 = The CAN Controller is disabled.
1 = The CAN Controller is enabled.
• LPM: Disable/Enable Low Power Mode
w Power Mode.
1 = Enable Low Power M
CAN controller enters Low Power Mode once all pending messages have been transmitted.
• ABM: Disable/Enable Autobaud/Listen mode
0 = Disable Autobaud/listen mode.
1 = Enable Autobaud/listen mode.
• OVL: Disable/Enable Overload Frame
0 = No overload frame is generated.
1 = An overload frame is generated after each successful reception for mailboxes configured in Receive with/without overwrite
Mode, Producer and Consumer.
• TEOF: Timestamp messages at each end of Frame
0 = The value of CAN_TIM is captured in the CAN_TIMESTP register at each Start Of Frame.
1 = The value of CAN_TIM is captured in the CAN_TIMESTP register at each End Of Frame.
• TTM: Disable/Enable Time Triggered Mode
0 = Time Triggered Mode is disabled.
1 = Time Triggered Mode is enabled.
• TIMFRZ: Enable Timer Freeze
0 = The internal timer continues to be incremented after it reached 0xFFFF.
1 = The internal timer stops incrementing after reaching 0xFFFF. It is restarted after a timer reset. See “Freezing the Internal
Timer Counter” on page 504.
• DRPT: Disable Repeat
31 30 29 28 27 26 25 24
––––– RXSYNC
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
DRPT TIMFRZ TTM TEOF OVL ABM LPM CANEN
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
0 = When a transmit mailbox loses the bus arbitration, the transfer request remains pending.
1 = When a transmit mailbox lose the bus arbitration, the transfer request is automatically aborted. It automatically raises the
MABT and MRDT flags in the corresponding CAN_MSRx.
• RXSYNC: Reception Synchronization Stage (not readable)
This field allows configuration of the reception stage of the macrocell (for debug purposes only)
RXSYNC Reception Synchronization Stage
0 Rx Signal with Double Synchro Stages (2 Positive Edges)
1 Rx Signal with Double Synchro Stages (One Positive Edge and One Negative Edge)
2 Rx Signal with Single Synchro Stage (Po sitive Edge)
others Rx Signal with No Synchro Stage
509
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.2 CAN Interrupt Enable Register
Name: CAN_IER
Access Type: Write-only
• MBx: Mailbox x Interrupt Enable
0 = No effect.
1 = Enable Mailbox x interrupt.
• ERRA: Error Active Mode Interrupt Enable
0 = No effect.
1 = Enable ERRA interrupt.
• WARN: Warning Limit Interrupt Enable
0 = No effect.
1 = Enable WARN interrupt.
• ERRP: Error Passive Mode Interrupt Enable
0 = No effect.
1 = Enable ERRP interrupt.
• BOFF: Bus Off Mode Interrupt Enable
0 = No effect.
1 = Enable BOFF interrupt.
• SLEEP: Sleep Interrupt Enable
0 = No effect.
1 = Enable SLEEP interrupt.
• WAKEUP: Wake up Interrupt Enable
0 = No effect.
1 = Enable SLEEP interrupt.
• TOVF: Timer Overflow Interrupt Enable
0 = No effect.
1 = Enable TOVF interrupt.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• TSTP: TimeStamp Interrupt Enable
0 = No effect.
1 = Enable TSTP interrupt.
• CERR: CRC Error Interrupt Enable
0 = No effect.
1 = Enable CRC Error interrupt.
• SERR: Stuffing Error Interrupt Enable
0 = No effect.
1 = Enable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Enable
0 = No effect.
1 = Enable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Enable
0 = No effect.
1 = Enable Form Error interrupt.
• BERR: Bit Error Interrupt Enable
0 = No effect.
1 = Enable Bit Error interrupt.
511
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.3 CAN Interrupt Disable Register
Name: CAN_IDR
Access Type: Write-only
• MBx: Mailbox x Interrupt Disable
0 = No effect.
1 = Disable Mailbox x interrupt.
• ERRA: Error Active Mode Interrupt Disable
0 = No effect.
1 = Disable ERRA interrupt.
• WARN: Warning Limit Interrupt Disable
0 = No effect.
1 = Disable WARN interrupt.
• ERRP: Error Passive Mode Interrupt Disable
0 = No effect.
1 = Disable ERRP interrupt.
• BOFF: Bus Off Mode Interrupt Disable
0 = No effect.
1 = Disable BOFF interrupt.
• SLEEP: Sleep Interrupt Disable
0 = No effect.
1 = Disable SLEEP interrupt.
• WAKEUP: Wake up Interrupt Disable
0 = No effect.
1 = Disable WAKEUP interrupt.
• TOVF: Timer Overflow Interrupt
0 = No effect.
1 = Disable TOVF interrupt.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
512
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• TSTP: TimeStamp Interrupt Disable
0 = No effect.
1 = Disable TSTP interrupt.
• CERR: CRC Error Interrupt Disable
0 = No effect.
1 = Disable CRC Error interrupt.
• SERR: Stuffing Error Interrupt Disable
0 = No effect.
1 = Disable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Disable
0 = No effect.
1 = Disable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Disable
0 = No effect.
1 = Disable Form Error interrupt.
• BERR: Bit Error Interrupt Disable
0 = No effect.
1 = Disable Bit Error interrupt.
513
SAM7X Series [DATASHEET]
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36.8.4 CAN Interrupt Mask Register
Name: CAN_IMR
Access Type: Read-only
• MBx: Mailbox x Interrupt Mask
0 = Mailbox x interrupt is disabled.
1 = Mailbox x interrupt is enabled.
• ERRA: Error Active Mode Interrupt Mask
0 = ERRA interrupt is disabled.
1 = ERRA interrupt is enabled.
• WARN: Warning Limit Interrupt Mask
0 = Warning Limit interrupt is disabled.
1 = Warning Limit interrupt is enabled.
• ERRP: Error Passive Mode Interrupt Mask
0 = ERRP interrupt is disabled.
1 = ERRP interrupt is enabled.
• BOFF: Bus Off Mode Interrupt Mask
0 = BOFF interrupt is disabled.
1 = BOFF interrupt is enabled.
• SLEEP: Sleep Interrupt Mask
0 = SLEEP interrupt is disabled.
1 = SLEEP interrupt is enabled.
• WAKEUP: Wake up Interrupt Mask
0 = WAKEUP interrupt is disabled.
1 = WAKEUP interrupt is enabled.
• TOVF: Timer Overflow Interrupt Mask
0 = TOVF interrupt is disabled.
1 = TOVF interrupt is enabled.
31 30 29 28 27 26 25 24
– – – BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
514
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• TSTP: Timestamp Interrupt Mask
0 = TSTP interrupt is disabled.
1 = TSTP interrupt is enabled.
• CERR: CRC Error Interrupt Mask
0 = CRC Error interrupt is disabled.
1 = CRC Error interrupt is enabled.
• SERR: Stuffing Error Interrupt Mask
0 = Bit Stuffing Error interrupt is disabled.
1 = Bit Stuffing Error interrupt is enabled.
• AERR: Acknowledgment Error Interrupt Mask
0 = Acknowledgment Error interrupt is disabled.
1 = Acknowledgment Error interrupt is enabled.
• FERR: Form Error Interrupt Mask
0 = Form Error interrupt is disabled.
1 = Form Error interrupt is enabled.
• BERR: Bit Error Interrupt Mask
0 = Bit Error interrupt is disabled.
1 = Bit Error interrupt is enabled.
515
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.5 CAN Status Register
Name: CAN_SR
Access Type: Read-only
• MBx: Mailbox x Event
0 = No event occurred on Mailbox x.
1 = An event occurred on Mailbox x.
An event corresponds to MRDY, MABT fields in the CAN_MSRx register.
• ERRA: Error Active Mode
0 = CAN controller is not in Error Active Mode.
1 = CAN controller is in Error Active Mode.
This flag is set depending on TEC and REC counter values. It is set when node is neither in Error Passive Mode nor in Bus Off
Mode.
This flag is automatically reset when above condition is not satisfied. Refer to Section 36.6.4.6 “Error Interrupt Handler” on page
492 for more information.
• WARN: Warning Limit
0 = CAN controller Warning Limit is not reached.
1 = CAN controller Warning Limit is reached.
This flag is set depending on TEC and REC counter values. It is set when at least one of the counter values exceeds 96.
This flag is automatically reset when above condition is not satisfied. Refer to Section 36.6.4.6 “Error Interrupt Handler” on page
492 for more information.
• ERRP: Error Passive Mode
0 = CAN controller is not in Error Passive Mode.
1 = CAN controller is in Error Passive Mode.
This flag is set depending on TEC and REC counters values.
A node is error passive when TEC counter is greater or equal to 128 (decimal) or when the REC counter is greater or equal to 128
(decimal).
This flag is automatically reset when above condition is not satisfied. Refer to Section 36.6.4.6 “Error Interrupt Handler” on page
492 for more information.
• BOFF: Bus Off Mode
0 = CAN controller is not in Bus Off Mode.
1 = CAN controller is in Bus Off Mode.
31 30 29 28 27 26 25 24
OVLSY TBSY RBSY BERR FERR AERR SERR CERR
23 22 21 20 19 18 17 16
TSTP TOVF WAKEUP SLEEP BOFF ERRP WARN ERRA
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
516
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
This flag is set depending on TEC counter value. A node is bus off when TEC counter is greater or equal to 256 (decimal).
This flag is automatically reset when above condition is not satisfied. Refer to Section 36.6.4.6 “Error Interrupt Handler” on page
492 for more information.
• SLEEP: CAN controller in Low power Mode
0 = CAN controller is not in low power mode.
1 = CAN controller is in low power mode.
This flag is automatically reset when Low power mode is disabled
• WAKEUP: CAN controller is not in Low power Mode
0 = CAN controller is in low power mode.
1 = CAN controller is not in low power mode.
When a WAKEUP event occurs, the CAN controller is synchronized with the bus activity. Messages can be transmitted or
received. The CAN controller clock must be available when a WAKEUP event occurs. This flag is automatically reset when the
CAN Controller enters Low Power mode.
• TOVF: Timer Overflow
0 = The timer has not rolled-over FFFFh to 0000h.
1 = The timer rolls-over FFFFh to 0000h.
This flag is automatically cleared by reading CAN_SR register.
• TSTP Timestamp
0 = No bus activity has been detected.
1 = A start of frame or an end of frame has been detected (according to the TEOF field in the CAN_MR register).
This flag is automatically cleared by reading the CAN_SR register.
• CERR: Mailbox CRC Error
0 = No CRC error occurred during a previous transfer.
1 = A CRC error occurred during a previous transfer.
A CRC error has been detected during last reception.
This flag is automatically cleared by reading CAN_SR register.
• SERR: Mailbox Stuffing Error
0 = No stuffing error occurred during a previous transfer.
1 = A stuffing error occurred during a previous transfer.
A form error results from the detection of more than five consecutive bit with the same polarity.
This flag is automatically cleared by reading CAN_SR register.
• AERR: Acknowledgment Error
0 = No acknowledgment error occurred during a previous transfer.
1 = An acknowledgment error occurred during a previous transfer.
An acknowledgment error is detected when no detection of the dominant bit in the acknowledge slot occurs.
This flag is automatically cleared by reading CAN_SR register.
• FERR: Form Error
0 = No form error occurred during a previous transfer
1 = A form error occurred during a previous transfer
517
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
A form error results from violations on one or more of the fixed form of the following bit fields:
– CRC delimiter
– ACK delimiter
– End of frame
– Error delimiter
– Overload delimiter
This flag is automatically cleared by reading CAN_SR register.
• BERR: Bit Error
0 = No bit error occurred during a previous transfer.
1 = A bit error occurred during a previous transfer.
A bit error is set when the bit value monitored on the line is different from the bit value sent.
This flag is automatically cleared by reading CAN_SR register.
• RBSY: Receiver busy
0 = CAN receiver is not receiving a frame.
1 = CAN receiver is receiving a frame.
Receiver busy. This status bit is set by hardware while CAN receiver is acquiring or monitoring a frame (remote, data, overload or
error frame). It is automatically reset when CAN is not receiving.
• TBSY: Transmitter busy
0 = CAN transmitter is not transmitting a frame.
1 = CAN transmitter is transmitting a frame.
Transmitter busy. This status bit is set by hardware while CAN transmitter is generating a frame (remote, data, overload or error
frame). It is automatically reset when CAN is not transmitting.
• OVLSY: Overload busy
0 = CAN transmitter is not transmitting an overload frame.
1 = CAN transmitter is transmitting a overload frame.
It is automatically reset when the bus is not transmitting an overload frame.
518
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.6 CAN Baudrate Register
Name: CAN_BR
Access Type: Read-write
Any modification on one of the fields of the CANBR register must be done while CAN module is disabled.
To compute the different Bit Timings, please refer to the Section 36.6.4.1 “CAN Bit Timing Configuration” on page 488.
• PHASE2: Phase 2 segment
This phase is used to compensate the edge phase error.
Warning: PHASE2 value must be different from 0.
• PHASE1: Phase 1 segment
This phase is used to compensate for edge phase error.
• PROPAG: Programming time segment
This part of the bit time is used to compensate for the physical delay times within the network.
• SJW: Re-synchronization jump width
To compensate for phase shifts between clock oscillators of different controllers on bus. The controller must re-synchronize on
any relevant signal edge of the current transmission. The synchronization jump width defines the maximum of clock cycles a bit
period may be shortened or lengthened by re-synchronization.
• BRP: Baudrate Prescaler.
This field allows user to program the period of the CAN system clock to determine the individual bit timing.
The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
• SMP: Sampling Mode
0 = The incoming bit stream is sampled once at sample point.
1 = The incoming bit stream is sampled three times with a period of a MCK clock period, centered on sample point.
SMP Sampling Mode is automatically disabled if BRP = 0.
31 30 29 28 27 26 25 24
–––––––SMP
23 22 21 20 19 18 17 16
–BRP
15 14 13 12 11 10 9 8
– – SJW – PROPAG
76543210
– PHASE1 – PHASE2
tPHS2 tCSC PHASE2 1+()×=
tPHS1 tCSC PHASE1 1+()×=
tPRS tCSC PROPAG 1+()×=
tSJW tCSC SJW 1+()×=
tCSC BRP 1+()MCK⁄=
519
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.7 CAN Timer Register
Name: CAN_TIM
Access Type: Read-only
• TIMERx: Timer
This field represents the internal CAN controller 16-bit timer value.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TIMER15 TIMER14 TIMER13 TIMER12 TIMER11 TIMER10 TIMER9 TIMER8
76543210
TIMER7 TIMER6 TIMER5 TIMER4 TIMER3 TIMER2 TIMER1 TIMER0
520
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.8 CAN Timestamp Register
Name: CAN_TIMESTP
Access Type: Read-only
• MTIMESTAMPx: Timestamp
This field represents the internal CAN controller 16-bit timer value.
If the TEOF bit is cleared in the CAN_MR register, the internal Timer Counter value is captured in the MTIMESTAMP field at each
start of frame. Else the value is captured at each end of frame. When the value is captured, the TSTP flag is set in the CAN_SR
register. If the TSTP mask in the CAN_IMR register is set, an interrupt is generated while TSTP flag is set in the CAN_SR regis-
ter. This flag is cleared by reading the CAN_SR register.
Note: The CAN_TIMESTP register is reset when the CAN is disabled then enabled thanks to the CANEN bit in the
CAN_MR.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
MTIMESTAMP15 MTIMESTAMP14 MTIMESTAMP13 MTIMESTAMP12 MTIMESTAMP11 MTIMESTAMP10 MTIMESTAMP9 MTIMESTAMP8
76543210
MTIMESTAMP7 MTIMESTAMP6 MTIMESTAMP5 MTIMESTAMP4 MTIMESTAMP3 MTIMESTAMP2 MTIMESTAMP1 MTIMESTAMP0
521
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.9 CAN Error Counter Register
Name: CAN_ECR
Access Type: Read-only
• REC: Receive Error Cou n ter
When a receiver detects an error, REC will be increased by one, except when the detected error is a BIT ERROR while sending
an ACTIVE ERROR FLAG or an OVERLOAD FLAG.
When a receiver detects a dominant bit as the first bit after sending an ERROR FLAG, REC is increased by 8.
When a receiver detects a BIT ERROR while sending an ACTIVE ERROR FLAG, REC is increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVERLOAD
FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each sequence of addi-
tional eight consecutive dominant bits, each receiver increases its REC by 8.
After successful reception of a message, REC is decreased by 1 if it was between 1 and 127. If REC was 0, it stays 0, and if it was
greater than 127, then it is set to a value between 119 and 127.
• TEC: Transmit Error Counter
When a transmitter sends an ERROR FLAG, TEC is increased by 8 except when
– the transm itt er is error pa ssive and detects an ACKNOWLEDGMENT ERROR because of not detect in g a
dominant ACK and does not detect a dominant bit while sending its PASSIVE ERROR FLAG.
– the transmitter sends an ERR OR FLAG because a STUFF ERROR occurred during arbitration and should
have been recessive and has been sent as recessive but monitored as dominant.
When a transmitter detects a BIT ERROR while sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG, the TEC will be
increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVERLOAD
FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each sequence of addi-
tional eight consecutive dominant bits every transmitter increases its TEC by 8.
After a successful transmission the TEC is decreased by 1 unless it was already 0.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
TEC
15 14 13 12 11 10 9 8
––––––––
76543210
REC
522
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.10 CAN Transfer Command Register
Name: CAN_TCR
Access Type: Write-only
This register initializes several transfer requests at the same time.
• MBx: Transfer Request for Mailbox x
This flag clears the MRDY and MABT flags in the corresponding CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn, starting with the mailbox
with the highest priority. If several mailboxes have the same priority, then the mailbox with the lowest number is sent first (i.e.,
MB0 will be transferred before MB1).
• TIMRST: Timer Reset
Resets the internal timer counter. If the internal timer counter is frozen, this command automatically re-enables it. This command
is useful in Time Triggered mode.
31 30 29 28 27 26 25 24
TIMRST–––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
Mailbox Object Type Description
Receive It receives the next message.
Receive with overwrite This triggers a new reception.
Tr ansmit Sends data prepared in the mailbox as soon as possible.
Consumer Sends a remote frame.
Producer Sends data prepared in the mailbox after receiving a remote frame from a
consumer.
523
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.11 CAN Abort Command Register
Name: CAN_ACR
Access Type: Write-only
This register initializes several abort requests at the same time.
• MBx: Abort Request for Mailbox x
It is possible to set MACR field (in the CAN_MCRx register) for each mailbox.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
MB7MB6MB5MB4MB3MB2MB1MB0
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Transmit Cancels transfer request if the message has not been tran smitted to the
CAN transceiver.
Consumer Cancels the current transfer before the remote frame has been sent.
Producer Cancels the current transfer. The next remote frame is not serviced.
524
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.12 CAN Message Mode Register
Name: CAN_MMRx
Access Type: Read-write
• MTIMEMARK: Mailbox Timemark
This field is active in Time Triggered Mode. Transmit operations are allowed when the internal timer counter reaches the Mailbox
Timemark. See “Transmitting within a Time Window” on page 504.
In Timestamp Mode, MTIMEMARK is set to 0.
• PRIOR: Mailbox Priority
This field has no effect in receive and receive with overwrite modes. In these modes, the mailbox with the lowest number is ser-
viced first.
When several mailboxes try to transmit a message at the same time, the mailbox with the highest priority is serviced first. If sev-
eral mailboxes have the same priority, the mailbox with the lowest number is serviced first (i.e., MBx0 is serviced before MBx 15 if
they have the same priority).
• MOT: Mailbox Object Type
This field allows the user to define the type of the mailbox. All mailboxes are independently configurable. Five different types are
possible for each mailbox:
31 30 29 28 27 26 25 24
––––– MOT
23 22 21 20 19 18 17 16
–––– PRIOR
15 14 13 12 11 10 9 8
MTIMEMARK15 MTIMEMARK14 MTIMEMARK13 MTIMEMARK12 MTIMEMARK11 MTIMEMARK10 MTIMEMARK9 MTIMEMARK8
76543210
MTIMEMARK7 MTIMEMARK6 MTIMEMARK5 MTIMEMARK4 MTIMEMARK3 MTIMEMARK2 MTIMEMARK1 MTIMEMARK0
MOT Mailbox Object Type
000
Mailbox is disabled. This prevents receiving or transmitting any messages
with this mailbox.
001
Reception Mailbox. Mailbox is configured for reception. If a message is
received while the mailbox data register is full, it is discarded.
010
Reception mailbox with overwrite. Mailbox is configured for reception. If a
message is received while the mailbox is full, it overwr i te s th e previous
message.
0 1 1 Transmit mailbox. Mailbox is configured for transmission.
100
Consumer Mailbox. Mailbox is configured in reception but behaves as a
Tr ansmit Mailbox, i.e., it sends a remote frame and waits for an answer.
101
Producer Mailbox. Mailbox is configured in transmission but also behaves
like a reception mailbox, i.e., it waits to receive a Remote Frame before
sending its contents.
1 1 X Reserved
525
SAM7X Series [DATASHEET]
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36.8.13 CAN Message Acceptance Mask Register
Name: CAN_MAMx
Access Type: Read-write
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to CAN_MAMx
registers.
• MIDvB: Complementary bits for identifier in extended frame mode
Acceptance mask for corresponding field of the message IDvB register of the mailbox.
• MIDvA: Identi fier for standard frame mode
Acceptance mask for corresponding field of the message IDvA register of the mailbox.
• MIDE: Identifier Version
0= Compares IDvA from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
1= Compares IDvA and IDvB from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
31 30 29 28 27 26 25 24
– – MIDE MIDvA
23 22 21 20 19 18 17 16
MIDvA MIDvB
15 14 13 12 11 10 9 8
MIDvB
76543210
MIDvB
526
SAM7X Series [DATASHEET]
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36.8.14 CAN Message ID Register
Name: CAN_MIDx
Access Type: Read-write
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to CAN_MIDx
registers.
• MIDvB: Complementary bits for identifier in extended frame mode
If MIDE is cleared, MIDvB value is 0.
• MIDE: Identifier Version
This bit allows the user to define the version of messages processed by the mailbox. If set, mailbox is dealing with version 2.0
Part B messages; otherwise, mailbox is dealing with version 2.0 Part A messages.
• MIDvA: Identi fier for standard frame mode
31 30 29 28 27 26 25 24
– – MIDE MIDvA
23 22 21 20 19 18 17 16
MIDvA MIDvB
15 14 13 12 11 10 9 8
MIDvB
76543210
MIDvB
527
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.15 CAN Message Family ID Register
Name: CAN_MFIDx
Access Type: Read-only
• MFID: Family ID
This field contains the concatenation of CAN_MIDx register bits masked by the CAN_MAMx register. This field is useful to speed
up message ID decoding. The message acceptance procedure is described below.
As an example: CAN_MIDx = 0x305A4321
CAN_MAMx = 0x3FF0F0FF
CAN_MFIDx = 0x000000A3
31 30 29 28 27 26 25 24
––– MFID
23 22 21 20 19 18 17 16
MFID
15 14 13 12 11 10 9 8
MFID
76543210
MFID
528
SAM7X Series [DATASHEET]
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36.8.16 CAN Message Status Register
Name: CAN_MSRx
Access Type: Read-only
These register fields are updated each time a message transfer is received or aborted.
MMI is cleared by reading the CAN_MSRx register.
MRDY, MABT are cleared by writing MTCR or MACR in the CAN_MCRx register.
Warning: MRTR and MDLC state depends partly on the mailbox object type.
• MTIMESTAMP: Timer value
This field is updated only when time-triggered operations are disabled (TTM cleared in CAN_MR register). If the TEOF field in the
CAN_MR register is cleared, TIMESTAMP is the internal timer value at the start of frame of the last message re ceived or sent by
the mailbox. If the TEOF field in the CAN_MR register is set, TIMESTAMP is the internal timer value at the end of frame of the last
message received or sent by the mailbox.
In Time Triggered Mode, MTIMESTAMP is set to 0.
• MDLC: Mailbox Data Length Code
31 30 29 28 27 26 25 24
–––––––
MMI
23 22 21 20 19 18 17 16
MRDY MABT – MRTR MDLC
15 14 13 12 11 10 9 8
MTIMESTAMP15 MTIMESTAMP14 MTIMESTAMP13 MTIMESTAMP12 MTIMESTAMP11 MTIMESTAMP10 MTIMESTAMP9 MTIMESTAMP8
76543210
MTIMESTAMP7 MTIMESTAMP6 MTIMESTAMP5 MTIMESTAMP4 MTIMESTAMP3 MTIMESTAMP2 MTIMESTAMP1 MTIMESTAMP0
Mailbox Object Type Description
Receive Length of the first mailbox message receive d
Receive with overwrite Length of the last mailbox message received
Tr ansmit No action
Consumer Length of the mailb ox message received
Producer Length of the mailbox message to be sent after the remote frame reception
529
SAM7X Series [DATASHEET]
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• MRTR: Mailbox Remote Transmission Request
• MABT: Mailbox Message Abort
An interrupt is triggered when MABT is set.
0 = Previous transfer is not aborted.
1 = Previous transfer has been aborted.
This flag is cleared by writing to CAN_MCRx register
• MRDY: Mailbox Ready
An interrupt is triggered when MRDY is set.
0 = Mailbox data registers can not be read/written by the software application. CAN_MDx are locked by the CAN_MDx.
1 = Mailbox data registers can be read/written by the software application.
This flag is cleared by writing to CAN_MCRx register.
Mailbox Object Type Description
Receive The first frame received has the RTR bit set.
Receive with overwrite The last frame received has the RTR bit set.
Transmit Reserved
Consumer Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 1.
Producer Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 0.
Mailbox Object Type Description
Receive Reserved
Receive with overwrite Reserved
Tr ansmit Previous transfer has been aborted
Consumer The remote frame transfer request has been aborted.
Producer The response to the remote frame transfer has been aborted.
Mailbox Object Type Description
Receive At least one message has been received since the last mailbox transfer order . Data from the first frame
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Receive with overwrite At least one frame has been received since the last mailbox transfer order. Data from the last frame
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Transmit Mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
Consumer At least one message has been received since the last mailbox transfer order. Data from the first message
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Producer A remote frame has been received, mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
530
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• MMI: Mailbox Message Ignored
0 = No message has been ignored during the previous transfer
1 = At least one message has been ignored during the previous transfer
Cleared by reading the CAN_MSRx register.
Mailbox Object Type Description
Receive Set when at least two messages intended for the mailbox have been sent. The first one is available in the
mailbox data register. Others have been ignored. A mail box with a lower priority may have accepted the
message.
Receive with overwrite Set when at least two messages intended for the mailbox have been sent. The last one is available in the
mailbox data register. Previous ones ha ve been lost.
Transmit Reserved
Consumer A remote frame has been sent by the mailbox but several messages have been received. The first one is
available in the mailbox data register. Others have been ignored. Another mailbox with a lower priority may
have accepted the message.
Producer A remote frame has been received, but no data are available to be sent.
531
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.17 CAN Message Data Low Register
Name: CAN_MDLx
Access Type: Read-write
• MDL: Message Data Low Value
When MRDY field is set in the CAN_MSRx register, the lower 32 bits of a received message can be read or written by the soft-
ware application. Otherwise, the MDL value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDL value while the software application reads MDH and MDL regis-
ters. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in the
CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit in the
CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3. CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8. CAN_MDH[31:24]
31 30 29 28 27 26 25 24
MDL
23 22 21 20 19 18 17 16
MDL
15 14 13 12 11 10 9 8
MDL
76543210
MDL
532
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.18 CAN Message Data High Register
Name: CAN_MDHx
Access Type: Read-write
• MDH: Message Data High Value
When MRDY field is set in the CAN_MSRx register, the upper 32 bits of a received message are read or written by the software
application. Otherwise, the MDH value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDH value while the software application reads MDH and MDL regis-
ters. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in the
CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit in the
CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3. CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8. CAN_MDH[31:24]
31 30 29 28 27 26 25 24
MDH
23 22 21 20 19 18 17 16
MDH
15 14 13 12 11 10 9 8
MDH
76543210
MDH
533
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.19 CAN Message Control Register
Name: CAN_MCRx
Access Type: Write-only
• MDLC: Mailbox Data Length Code
• MRTR: Mailbox Remote Transmission Request
Consumer situations can be handled automatically by setting the mailbox object type in Consumer. This requires only one
mailbox.
It can also be handled using two mailboxes, one in reception, the other in transmission. The MRTR and the MTCR bits must be
set in the same time.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
MTCR MACR – MRTR MDLC
15 14 13 12 11 10 9 8
––––––––
76543210
––––––––
Mailbox Object Type Description
Receive No action.
Receive with overwrite No action.
Transmit Length of the mailbox message.
Consumer No action.
Producer Length of the mailb ox message to be sent after the remote frame
reception.
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Tr ansmit Set the RTR bit in the sent frame
Consumer No action, the RTR bit in the sent frame is set automatically
Producer No action
534
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• MACR: Abort Request for Mailbox x
It is possible to set MACR field for several mailboxes in the same time, setting several bits to the CAN_ACR register.
• MTCR: Mailbox Transfer Command
This flag clears the MRDY and MABT flags in the CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn. The mailbox with the high-
est priority is serviced first. If several mailboxes have the same priority, the mailbox with the lowest number is serviced first (i.e.,
MBx0 will be serviced before MBx 15 if they have the same priority).
It is possible to set MTCR for several mailboxes at the same time by writing to the CAN_TCR register.
Mailbox Object Type Description
Receive No action
Receive with overwrite No action
Transmit Cancels transfer request if the message has not been transmitted to the
CAN transceiver.
Consumer Cancels the current transfer before the remote frame has been sent.
Producer Cancels the current transfer. The next remote frame will not be serviced.
Mailbox Object Type Description
Receive Allows the reception of the next message.
Receive with overwrite Triggers a new reception.
Tr ansmit Sends data prepared in the mailbox as soon as possible.
Consumer Sends a remote transmissi on frame.
Producer Sends data prepared in the mailbox after receiving a remote frame from a
Consumer.
535
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37. Ethernet MAC 10/100 (EMAC)
37.1 Overview
The EMAC module implements a 10/100 Ethernet MAC compatible with the IEEE 802.3 standard using an address
checker, statistics and control registers, receive and transmit blocks, and a DMA interface.
The address checker recognizes four specific 48-bit addresses and contains a 64-bit hash register for matching multicast
and unicast addresses. It can recognize the broadcast address of all ones, copy all frames, and act on an external
address match signal.
The statistics register block contains registers for counting various types of event associated with transmit and receive
operations. These registers, along with the status words stored in the receive buffer list, enable software to generate
network management statistics compatible with IEEE 802.3.
37.2 Block Diagram
Figure 37-1. EMAC Block Diagram
APB
Slave Register Interface
DMA Interface
Address Checker
Statistics Registers
Control Registers
Ethernet Receive
Ethernet Transmit
MDIO
MII/RMII
RX FIFO TX FIFO
ASB
Master
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SAM7X Series [DATASHEET]
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37.3 Functional Description
The EMAC has several clock domains:
System bus clock (AHB and APB): DMA and register blocks
Transmit clock : transmit block
Receive clock: receive and address checker blocks
The only system constraint is 160 MHz for the system bus clock, above which MDC would toggle at above 2.5 MHz.
The system bus clock must run at least as fast as the receive clock and transmit clock (25 MHz at 100 Mbps, and 2.5
MHz at 10 Mbps).
Figure 37-1 illustrates the different blocks of the EMAC module.
The control registers drive the MDIO interface, setup up DMA activity, start frame transmission and select modes of
operation such as full- or half-duplex.
The receive block checks for valid preamble, FCS, alignment and length, and presents received frames to the address
checking block and DMA interface.
The transmit block takes data from the DMA interface, adds preamble and, if necessary, pad and FCS, and transmits
data according to the CSMA/CD (carrier sense multiple access with collision detect) protocol. The start of transmission is
deferred if CRS (carrier sense) is active.
If COL (collision) becomes active during transmission, a jam sequence is asserted and the transmission is retried after a
random back off. CRS and COL have no effect in full duplex mode.
The DMA block connects to external memory through its ASB bus interface. It contains receive and transmit FIFOs for
buffering frame data. It loads the transmit FIFO and empties the receive FIFO using ASB bus master operations. Receive
data is not sent to memory until the address checking logic has determined that the frame should be copied. Receive or
transmit frames are stored in one or more buffers. Receive buffers have a fixed length of 128 bytes. Transmit buffers
range in length between 0 and 2047 bytes, and up to 128 buffers are permitted per frame. The DMA block manages the
transmit and receive framebuffer queues. These queues can hold multiple frames.
37.3.1 Memory Interface
Frame data is transferred to and from the EMAC through the DMA interface. All transfers are 32-bit words and may be
single accesses or bursts of 2, 3 or 4 words. Burst accesses do not cross sixteen-byte boundaries. Bursts of 4 words are
the default data transfer; single accesses or bursts of less than four words may be used to transfer data at the beginning
or the end of a buffer.
The DMA controller performs six types of operation on the bus. In order of priority, these are:
1. Receive buffer manager write
2. Receive buffer manager read
3. Transmit data DMA read
4. Receive data DMA write
5. Transmit buffer manager read
6. Transmit buffer manager write
37.3.1.1 FIFO
The FIFO depths are 28 bytes and 28 bytes and area function of the system clock speed, memory latency and network
speed.
Data is typically transferred into and out of the FIFOs in bursts of four words. For receive, a bus request is asserted when
the FIFO contains four words and has space for three more. For transmit, a bus request is generated when there is
space for four words, or when there is space for two words if the next transfer is to be only one or two words.
Thus the bus latency must be less than the time it takes to load the FIFO and transmit or receive three words (12 bytes)
of data.
537
SAM7X Series [DATASHEET]
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At 100 Mbit/s, it takes 960 ns to transmit or receive 12 bytes of data. In addition, six master clock cycles should be
allowed for data to be loaded from the bus and to propagate through the FIFOs. For a 60 MHz master clock this takes
100 ns, making the bus latency requirement 860 ns.
37.3.1.2 Receive Buffers
Received frames, including CRC/FCS optionally, are written to receive buffers stored in memory. Each receive buffer is
128 bytes long. The start location for each receive buffer is stored in memory in a list of receive buffer descriptors at a
location pointed to by the receive buffer queue pointer register. The receive buffer start location is a word address. For
the first buffer of a frame, the start location can be offset by up to three bytes depending on the value written to bits 14
and 15 of the network configuration register. If the start location of the buffer is offset the available length of the first buffer
of a frame is reduced by the corresponding number of bytes.
Each list entry consists of two words, the first being the address of the receive buffer and the second being the receive
status. If the length of a receive frame exceeds the buffer length, the status word for the used buffer is written with zeroes
except for the “start of frame” bit and the offset bits, if appropriate. Bit zero of the address field is written to one to show
the buffer has been used. The receive buffer manager then reads the location of the next receive buffer and fills that with
receive frame data. The final buffer descriptor status word contains the complete frame status. Refer to Table 37-1 for
details of the receive buffer descriptor list.
Table 37-1. Receive Buffer Descriptor Entry
Bit Function
Word 0
31:2 Addre s s of beginning of buffer
1 Wrap - marks last descriptor in receive buffer descriptor list.
0Ownership - needs to be zero for the EMAC to write data to the receive buffer. The EMAC sets this to one once it has
successfully written a frame to memory.
Software has to clear this bit before the buffer can be used again.
Word 1
31 Global all on es broadcast address detected
30 Multicast hash match
29 Unicast hash match
28 External ad dress match
27 Reserved for future use
26 S pecific address register 1 match
25 S pecific address register 2 match
24 S pecific address register 3 match
23 S pecific address register 4 match
22 Type ID match
21 VLAN tag detected (i.e., type id of 0x8100)
20 Priority tag detected (i.e., type id of 0x8100 and null VLAN identifier)
19:17 VLAN priority (only valid if bit 21 is set)
16 Concatenation format indicator (CFI) bit (only valid if bit 21 is set)
15 End of frame - when set the buffer contains the end of a frame. If end of frame is not set, then the only other valid status
are bits 12, 13 and 14.
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SAM7X Series [DATASHEET]
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To receive frames, the buffer descriptors must be initialized by writing an appropriate address to bits 31 to 2 in the first
word of each list entry. Bit zero must be written with zero. Bit one is the wrap bit and indicates the last entry in the list.
The start location of the receive buffer descriptor list must be written to the receive buffer queue pointer register before
setting the receive enable bit in the network control register to enable receive. As soon as the receive block starts writing
received frame data to the receive FIFO, the receive buffer manager reads the first receive buffer location pointed to by
the receive buffer queue pointer register.
If the filter block then indicates that the frame should be copied to memory, the receive data DMA operation starts writing
data into the receive buffer. If an error occurs, the buffer is recovered. If the current buffer pointer has its wrap bit set o r is
the 1024th descriptor, the next receive buffer location is read from the beginning of the receive descriptor list. Otherwise,
the next receive buffer location is read from the next word in memory.
There is an 11-bit counter to count out the 2048 word locations of a maximum length, receive buffer descript or list. This is
added with the value originally written to the receive buffer queue pointer register to produce a pointer into the list. A read
of the receive buffer queue pointer register returns the pointer value, which is the queue entry currently being accessed.
The counter is reset after receive status is written to a descriptor that has its wrap bit set or rolls over to zero after 1024
descriptors have been accessed. The value written to the receive buffer pointer register may be any word-aligned
address, provided that there are at least 2048 word locations available between the pointer and the top of the memory.
Section 3.6 of the AMBA™ 2.0 specification states that bursts should not cross 1K boundaries. As receive buffer manager
writes are bursts of two words, to ensure that this does not occur, it is best to write the pointer register with the least three
significant bits set to zero. As receive buffers are used, the receive buffer manager sets bit zero of the first word of the
descriptor to indicate used. If a receive error is detected the receive buffer currently being written is recovered. Previous
buffers are not recovered. Software should search through the used bits in the buffer descriptors to find out how many
frames have been received. It should be checking the start-of-frame and end-of-frame bits, and not rely on the value
returned by the receive buffer queue pointer register which changes continuously as more buffers are used.
For CRC errored frames, excessive length frames or length field mismatched frames, all of which are counted in the
statistics registers, it is possible that a frame fragment might be stored in a sequence of receive buffers. Software can
detect this by looking for start of frame bit set in a buffer following a buffer with no end of frame bit set.
For a properly working Ethernet system, there should be no excessively long frames or frames greater than 128 bytes
with CRC/FCS errors. Collision fragments are less than 128 bytes long. Therefore, it is a rare occurrence to find a frame
fragment in a receive buffer.
If bit zero is set when the receive buffer manager reads the location of the receive buffer, then the buffer has already
been used and cannot be used again until software has processed th e frame and cleared bit zero. In this case, the DMA
block sets the buffer not available bit in the receive status register and triggers an interrupt.
If bit zero is set when the receive buffer manager reads the location of the receive buffer and a frame is being received,
the frame is discarded and the receive resource error statistics register is incremented.
A receive overrun condition occurs when bus was not granted in time or because HRESP was not OK (bus error). In a
receive overrun condition, the receive overrun interrupt is asserted and the buffer currently being written is recovered.
The next frame received with an address that is recognized reuses the buffer.
If bit 17 of the network configuration register is set, the FCS of received frames shall not be copied to memory. The frame
length indicated in the receive status field shall be reduced by four bytes in this case.
14 Start of frame - when set the buffer contains the start of a frame. If both bits 15 and 14 are set, then the buffer contains a
whole frame.
13:12
Receive buffer offset - indicates the number of bytes by which the data in the first buffer is offset from the word address.
Updated with the current values of the network configuration register . If jumbo frame mode is enabled through bit 3 of the
network configuration register, then bits 13:12 of the receive buffer descriptor entry are used to indicate bits 13:12 of the
frame length.
11:0 Length of frame including FCS (if selected). Bits 13:12 are also used if jumbo frame mode is selected.
Table 37-1. Receive Buffer Descriptor Entry (Continued)
Bit Function
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37.3.1.3 Transmit Buffer
Frames to be transmitted are stored in one or more transmit buffers. Transmit buffers can be between 0 and 2047 bytes
long, so it is possible to transmit frames longer than the maximum length specified in IEEE Standard 802.3. Zero length
buffers are allowed. The maximum number of buffers permitted for each transmit frame is 128.
The start location for each transmit buffer is stored in memory in a list of transmit buffer descriptors at a location pointed
to by the transmit buffer queue pointer register. Each list entry consists of two words, the first being the byte address of
the transmit buffer and the second containing the transmit control and status. Frames can be transmitted with or without
automatic CRC generation. If CRC is automatically generated, pad is also automatically generated to take frames to a
minimum length of 64 bytes. Table 37-2 on page 539 defines an entry in the transmit buffer descriptor list. To transmit
frames, the buffer descriptors must be initialized by writing an appropriate byte address to bits 31 to 0 in the first word of
each list entry. The second transmit buffer descriptor is initialized with control information that indicates the length of the
buffer, whether or not it is to be transmitted with CRC and whether the buffer is the last buffer in the frame.
After transmission, the control bits are written back to the second word of the first buffer along with the “used” bit and
other status information. Bit 31 is the “used” bit which must be zero when the control word is read if transmission is to
happen. It is written to one when a frame has been transmitted. Bits 27, 28 and 29 indicate various transmit error
conditions. Bit 30 is the “wrap” bit which can be set for any buffer with in a frame. If no wrap bit is encountered after 1024
descriptors, the queue pointer rolls over to the start in a similar fashion to the receive queue.
The transmit buffer queue pointer register must not be written while transmit is active. If a new value is written to the
transmit buffer queue pointer register, the queue pointer resets itself to point to the beginning of the new queue. If
transmit is disabled by writing to bit 3 of the network control, the transmit buffer queue pointer register resets to point to
the beginning of the transmit queue. Note that disabling receive does not have the same effect on the receive queue
pointer.
Once the transmit queue is initialized, transmit is activated by writing to bit 9, the Transmit Start bit of the network control
register. Transmit is halted when a buffer descriptor with its us ed bit set is read, or if a transmit error occurs, or by writing
to the transmit halt bit of the network control register. (Transmission is suspended if a pause frame is received while the
pause enable bit is set in the network config uration register.) Rewriting the start bit while transmission is active is allowed.
Transmission control is implemented with a Tx_go variable which is readable in the transmit status register at bit location
3. The Tx_go variable is reset when:
transmit is disabled
a buffer descriptor with its ownership bit set is read
a new value is written to the transmit buffer queue pointer register
bit 10, tx_halt, of the network control register is written
there is a transmit error such as too many retries or a transmit underrun.
To set tx_go, write to bit 9, tx_start, of the network control register. Transmit halt does not take effect until any ongoing
transmit finishes. If a collision occurs during transmission of a multi-buffer frame, transmission automatically restarts from
the first buffer of the frame. If a “used” bit is read midway through transmission of a multi-buffer frame, this is treated as a
transmit error. Transmission stops, tx_er is asserted and the FCS is bad.
If transmission stops due to a transmit error, the transmit queue pointer resets to point to the beginning of the transmit
queue. Software needs to re-initialize the transmit queue after a transmit error.
If transmission stops due to a “used” bit being read at the start of the frame, the transmission queue pointer is not reset
and transmit starts from the same transmit buffer descriptor when the transmit start bit is written
Table 37-2. Transmit Buffer Descriptor Entry
Bit Function
Word 0
31:0 Byte Address of buffer
Word 1
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37.3.2 Transmit Block
This block transmits frames in accordance with the Ethernet IEEE 802.3 CSMA/CD protocol. Frame assembly starts by
adding preamble and the start frame delimiter. Data is taken from the transmit FIFO a word at a time. Data is transmitted
least significant nibble first. If necessary, padding is added to increase the frame length to 60 bytes. CRC is calculated as
a 32-bit polynomial. This is inverted and appended to the end of the frame, taking the frame length to a minimum of 64
bytes. If the No CRC bit is set in the second word of the last buffer descriptor of a transmit frame, neither pad nor CRC
are appended.
In full-duplex mode, frames are transmitted immediately. Back-to-back frames are transmitted at least 96 bit times apart
to guarantee the interframe gap.
In half-duplex mode, the transmitter checks carrier sense. If asserted, it waits for it to de-assert and then starts
transmission after the interframe gap of 96 bit times. If the collision signal is asserted during transmission, the transmitter
transmits a jam sequence of 32 bits taken from the data register and then retry transmission after the back off time has
elapsed.
The back-off time is based on an XOR of the 10 least significant bits of the data coming from the transmit FIFO and a 10-
bit pseudo random number generator. The number of bits used depends on the number of collisions seen. After the first
collision, 1 bit is used, after the second 2, and so on up to 10. Above 10, all 10 bits are used. An error is indicated and no
further attempts are made if 16 attempts cause collisions.
If transmit DMA underruns, bad CRC is automatically appended using the same mechanism as jam insertion and the
tx_er signal is asserted. For a properly configured system, this should never happen.
If the back pressure bit is set in the network control register in half duplex mode, the transmit block transmits 64 bits of
data, which can consist of 16 nibbles of 1011 or in bit-rate mode 64 1s, whenever it sees an incoming frame to force a
collision. This provides a way of implementing flow control in half-duplex mode.
31
Used. Needs to be zero for the EMAC to read data from the transmit buffer . The EMAC set s this to one for the first buffer
of a frame once it has been successfully transmitted.
Software has to clear this bit before the buffer can be used again.
Note: This bit is only set for the first buffer in a frame unlike receive where all buffers have the Used bit set once
used.
30 Wrap. Marks last descriptor in transmit buffer descriptor list.
29 Retry limit exceeded, transmit error detected
28 Transmit underrun, occurs either when hresp is not OK (bus error) or the transmit data could not be fetched in time or
when buffers are exhausted in mid frame.
27 Buffers exhausted in mid frame
26:17 Reserved
16 No CRC. When set, no CRC is appended to the current frame. This bit only needs to be set for the last buffer of a frame.
15 Last buffer. When set, this bit indicates the last buffer in the current frame has been reached.
14:11 Reserved
10:0 Length of buffer
Table 37-2. Transmit Buffer Descriptor Entry (Continued)
Bit Function
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37.3.3 Pause Frame Support
The start of an 802.3 pause frame is as follows:
The network configuration register contains a receive pause enable bit (13). If a valid pause frame is received, the pause
time register is updated with the frame’s pause time, regardless of its current contents and regardless of the state of the
configuration register bit 13. An interrupt (12) is triggered when a pause frame is received, assuming it is enabled in the
interrupt mask register. If bit 13 is set in the network configuration register and the value of the pause time register is non-
zero, no new frame is transmitted until the pause time register has decremented to zero.
The loading of a new pause time, and hence the pausing of transmission, only occurs when the EMAC is configured for
full-duplex operation. If the EMAC is configured for half-duplex, there is no transmission pause, but the pause frame
received interrupt is still triggered.
A valid pause frame is defined as having a destination address that matches either the address stored in specific address
register 1 or matches 0x0180C2000001 and has the MAC control frame type ID of 0x8808 and the pause opcode of
0x0001. Pause frames that have FCS or other errors are treated as invalid and are discarded. Valid pause frames
received increment the Pause Frame Received statistic register.
The pause time register decrements every 512 bit times (i.e., 128 rx_clks in nibble mode) once transmission has
stopped. For test purposes, the register decrements every rx_clk cycle once transmission has stopped if bit 12 (retry
test) is set in the network configuration register. If the pause enable bit (13) is not set in the network configuration
register, then the decrementing occurs regardless of whether transmission has stopped or not.
An interrupt (13) is asserted whenever the pause time register decrements to zero (assuming it is enabled in the interrupt
mask register).
37.3.4 Receive Block
The receive block checks for valid preamble, FCS, alignment and length, presents received frames to the DMA block and
stores the frames destination address for use by the address checking block. If, during frame reception, the frame is
found to be too long or rx_er is asserted, a bad frame indication is sent to the DMA block. The DMA block then ceases
sending data to memory. At the end of frame reception, the receive block indicates to the DMA block whether the frame
is good or bad. The DMA block recovers the current receive buffer if the frame was bad. The receive block signals the
register block to increment the alignment error, the CRC (FCS) error, the short frame, long frame, jabber error, the
receive symbol error statistics and the length field mismatch statistics.
The enable bit for jumbo frames in the network configuration register allows the EMAC to receive jumbo frames of up to
10240 bytes in size. This operation does not form part of the IEEE802.3 specification and is disabled by default. When
jumbo frames are enabled, frames received with a frame size greater than 10240 bytes are discarded.
37.3.5 Address Checking Block
The address checking (or filter) block indicates to the DMA block which receive frames should be copied to memory.
Whether a frame is copied depends on what is enabled in the network configuration register, the state of the external
match pin, the contents of the specific address and hash registers and the frame’s destination address. In this
implementation of the EMAC, the frame’s source address is not checked. Provided that bit 18 of the Network
Configuration register is not set, a frame is not copied to memory if the EMAC is transmitting in half duplex mode at the
time a destination address is received. If bit 18 of the Network Configuration register is set, frames can be received while
transmitting in half-duplex mode.
Ethernet frames are transmitted a byte at a time, least significant bit first. The first six bytes (48 bits) of an Ethernet frame
make up the destination address. The first bit of the destination address, the LSB of the first byte of the frame, is the
Table 37-3 . Start of an 802.3 Pause Frame
Destination
Address Source
Address Type
(Mac Control Frame) Pause
Opcode Pause Time
0x0180C2000001 6 bytes 0x8808 0x0001 2 bytes
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group/individual bit: this is One for multicast addresses and Zero for unicast. The All Ones address is the broadcast
address, and a special case of multicast.
The EMAC supports recognition of four specific addresses. Each specific address requires two registers, specific
address register bottom and specific address register top. Specific address register bottom stores the first four bytes of
the destination address and specific address register top contains the last two bytes. The addresses stored can be
specific, group, local or universal.
The destination address of received frames is compared against the data stored in the specific address registers once
they have been activated. The addresses are deactivated at reset or when their corresponding specific address register
bottom is written. They are activated when specific address register top is written. If a receive fra me address matches an
active address, the frame is copied to memory.
The following example illustrates the use of the address match registers for a MAC address of 21:43:65:87:A9:CB.
Preamble 55
SFD D5
DA (Octet0 - LSB) 21
DA(Octet 1) 43
DA(Octet 2) 65
DA(Octet 3) 87
DA(Octet 4) A9
DA (Octet5 - MSB) CB
SA (LSB) 00
SA 00
SA 00
SA 00
SA 00
SA (MSB) 43
SA (LSB) 21
The sequence above shows the beginning of an Ethernet frame. Byte order of transmission is from top to bottom as
shown. For a successful match to specific address 1, the following address matching registers must be set up:
Base address + 0x98 0x87654321 (Bottom)
Base address + 0x9C 0x0000CBA9 (Top)
And for a successful match to the Type ID register, the following should be set up:
Base address + 0xB8 0x00004321
37.3.6 Broadcast Address
The broadcast address of 0xFFFFFF FFFFFF is recognized if the ‘no broadcast’ bit in the network configuration register is
zero.
37.3.7 Hash Addressing
The hash address register is 64 bits long and takes up two locations in the memory map. The least significant bits are
stored in hash register bottom and the most significant bits in hash register top.
The unicast hash enable and the multicast hash enable bits in the network configuration register enable the reception of
hash matched frames. The destination address is reduced to a 6-bit index into the 64-bit hash register using the following
hash function. The hash function is an exclusive or of every sixth bit of the destination address.
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hash_index[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
hash_index[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
hash_index[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
hash_index[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
hash_index[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
hash_index[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
da[0] represents the least significant bit of the first byte received, that is, the multicast/unicast indicator, and da[47]
represents the most significant bit of the last byte received.
If the hash index points to a bit that is set in the hash register, then the frame is matched according to whether the frame
is multicast or unicast.
A multicast match is signalled if the multicast hash enable bit is set. da[0] is 1 and the hash index points to a bit set in th e
hash register.
A unicast match is signalled if the unicast hash enable bit is set. da[0] is 0 and the hash index points to a bit set in the
hash register.
To receive all multicast frames, the hash register should be set with all ones and the multicast hash enable bit should be
set in the network configuration register.
37.3.8 Copy All Frames (or Promiscuous Mode)
If the copy all frames bit is set in the network configuration register, then all non-errored frames are copied to memory.
For example, frames that are too long, too short, or have FCS errors or rx_er asserted during reception are discarded
and all others are received. Frames with FCS errors are copied to memory if bit 19 in the network configuration register is
set.
37.3.9 Type ID Checking
The contents of the type_id register are compared against the length/type ID of received frames (i.e., bytes 13 and 14).
Bit 22 in the receive buffer descriptor status is set if there is a match. The reset state of this register is zero which is
unlikely to match the length/type ID of any valid Ethernet frame.
Note: A type ID match does not affect whether a frame is copied to memory.
37.3.10 VLAN Support
An Ethernet encoded 802.1Q VLAN tag looks like this:
The VLAN tag is inserted at the 13th byte of the frame, adding an extra four bytes to the frame. If the VID (VLAN identifier)
is null (0x000), this indicates a priority-tagged frame. The MAC can support frame lengths up to 1536 bytes, 18 bytes
more than the original Ethernet maximum frame length of 1518 bytes. This is achieved by setting bit 8 in the network
configuration register.
The following bits in the receive buffer descriptor status word give information about VLAN tagged frames:
Bit 21 set if receive frame is VLAN tagged (i.e. type id of 0x8100)
Bit 20 set if receive frame is priority tagged (i.e. type id of 0x8100 and null VID). (If bit 20 is set bit 21 is set also.)
Bit 19, 18 and 17 set to priority if bit 21 is set
Bit 16 set to CFI if bit 21 is set
Table 37-4. 802.1Q VLAN Tag
TPID (Tag Protocol Identifier) 16 bits TCI (Tag Control Information) 16 bits
0x8100 First 3 bits priority, then CFI bit, last 12 bits VID
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37.3.11 PHY Maintenance
The register EMAC_MAN enables the EMAC to communicate with a PHY by means of the MDIO interface. It is used
during auto-negotiation to ensure that the EMAC and the PHY are configured for the same speed and duplex
configuration.
The PHY maintenance register is implemented as a shift register. Writing to the register starts a shift operation which is
signalled as complete when bit two is set in the network status register (about 2000 MCK cycles later when bit ten is set
to zero, and bit eleven is set to one in the network configuration register). An interrupt is generated as this bit is set.
During this time, the MSB of the register is output on the MDIO pin and the LSB updated from the MDIO pin with each
MDC cycle. This causes transmission of a PHY management frame on MDIO.
Reading during the shift operation returns the current contents of the shift register. At the end of management opera tion,
the bits have shifted back to their original locations. For a read operation, the data bits are updated with data read from
the PHY. It is important to write the correct values to the register to ensure a valid PHY management frame is produced.
The MDIO interface can read IEEE 802.3 clause 45 PHYs as well as clause 22 PHYs. To read clause 45 PHYs,
bits[31:28] should be written as 0x0011. For a description of MDC generation, see the network configuration register in
the “Network Control Register” on page 550.
37.3.12 Media Independent Interface
The Ethernet MAC is capable of interfacing to both RMII and MII Interfaces. The RMII bit in the EMAC_USRIO register
controls the interface that is selected. When this bit is set, the RMII interface is selected, else the MII interface is
selected.
The MII and RMII interface are capable of both 10Mb/s and 100Mb/s data rates as described in the IEEE 802.3u
standard. The signals used by the MII and RMII interfaces are described in Table 37-5.
The intent of the RMII is to provide a reduced pin count alternative to the IEEE 802.3u MII. It uses 2 bits for transmit
(ETX0 and ETX1) and two bits for receive (ERX0 and ERX1). There is a Transmit Enable (ETXEN), a Receive Error
(ERXER), a Carrier Sense (ECRS_DV), and a 50 MHz Reference Clock (ETXCK_EREFCK) for 100Mb/s data rate.
37.3.12.1 RMII Transmit and Receive Operation
The same signals are used internally for both the RMII and the MII operations. The RMII maps these signals in a more
pin-efficient manner. The transmit and receive bits are converted from a 4-bit parallel format to a 2-bit parallel scheme
that is clocked at twice the rate. The carrier sense and data valid signals are combined into the ECRSDV signal. This
signal contains information on carrier sense, FIFO status, and validity of the data. Transmit error bit (ETXER) and
collision detect (ECOL) are not used in RMII mode.
Table 37-5. Pin Configuration
Pin Name MII RMII
ETXCK_EREFCK ETXCK: Transmit Clock EREFCK: Reference Clock
ECRS ECRS: Carrier Sense
ECOL ECOL: Collision Detect
ERXDV ERXDV: Data Valid ECRSDV: Carrier Sense/Data Valid
ERX0 - ERX3 ERX0 - ERX3: 4-bit Receive Data ERX0 - ERX1: 2-bit Receive Data
ERXER ERXER: Receive Error ERXER: Receive Error
ERXCK ERXCK: Receive Clock
ETXEN ETXEN: Transmit Enable ETXEN: Transmit Enable
ETX0-ETX3 ETX0 - ETX3: 4-bit Transmit Data ETX0 - ETX1: 2-bit Transmit Data
ETXER ETXER: Transmit Error
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37.4 Programming Interface
37.4.1 Initialization
37.4.1.1 Configuration
Initialization of the EMAC configuration (e.g., loop-back mode, frequency ratios) must be done while the transmit and
receive circuits are disabled. See the description of the net work control register and network configuration register earlier
in this document.
To change loop-back mode, the following sequence of operations must be followed:
1. Write to network control register to disable transmit and receive circuits.
2. Write to network control register to change loop-back mode.
3. Write to network control register to re-enable transmit or receive circuits.
Note: These writes to network control register cannot be combined in any way.
37.4.1.2 Receive Buffer List
Receive data is written to areas of data (i.e., buffers) in system memory. These buffers are listed in another data
structure that also resides in main memory. This data structure (receive buffer queue) is a sequence of descriptor entries
as defined in “Receive Buffer Descriptor Entry” on page 537. It points to this data structure.
Figure 37-2. Receive Buffer List
To create the list of buffers:
1. Allocate a number (n) of buffers of 128 bytes in system memory.
2. Allocate an area 2n words for the receive buf fer descriptor entry in system memory and create n entries in this list.
Mark all entries in this list as owned by EMAC, i.e., bit 0 of word 0 set to 0.
3. If less than 1024 buffers are defined, the last descriptor must be marked with the wrap bit (bit 1 in word 0 set to 1).
4. Write address of receive buffer descriptor entry to EMAC register receive_buffer queue pointer.
5. The receive circuits can then be enabled by writing to the address recognition registers and then to the network
control register.
37.4.1.3 Transmit Buffer List
Transmit data is read from areas of data (the buffers) in system memory These buffers are listed in another data
structure that also resides in main memory. This data structure (Transmit Buffer Queue) is a sequence of descriptor
entries (as defined in Table 37-2 on page 539) that points to this data structure.
To create this list of buffers:
Receive Buffer Queue Pointer
(MAC Register)
Receive Buffer 0
Receive Buffer 1
Receive Buffer N
Receive Buffer Descriptor List
(In memory)
(In memory)
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1. Allocate a number (n) of buffers of between 1 and 2047 bytes of data to be transmitted in system memory. Up to
128 buffers per frame are allowed.
2. Allocate an area 2n words for the transmit buffer descriptor entry in system memory and create N entries in this
list. Mark all entries in this list as owned by EMAC, i.e. bit 31 of word 1 set to 0.
3. If fewer than 1024 buffers are defined, the last descriptor must be marked with the wrap bit — bit 30 in word 1 set
to 1.
4. Write address of transmit buffer descriptor entry to EMAC register transmit_buffer queue pointer.
5. The transmit circuits can then be enabled by writing to the network control register.
37.4.1.4 Address Matching
The EMAC register-pair hash address and the four specific address register-pairs must be written with the required
values. Each register-pair comprises a bottom register and top register, with the bottom register being written first. The
address matching is disabled for a particular register-pair after the bottom-register has been written and re-enabled when
the top register is written. See “Address Checking Blo ck” on page 541. for details of address matching. Each register-pair
may be written at any time, regardless of whether the receive circuits are enabled or disabled.
37.4.1.5 Interrupts
There are 14 interrupt conditions that are detected within the EMAC. These are ORed to make a single interrupt.
Depending on the overall system design, this may be passed through a further level of interrupt collection (interrupt
controller). On receipt of the interrupt signal, the CPU enters the interrupt handler (Refer to the AIC programmer
datasheet). To ascertain which interrupt has been generated, read the interrupt status register. Note that this register
clears itself when read. At reset, all interrupts are disabled. To enable an interrupt, write to interrupt enable register with
the pertinent interrupt bit set to 1. To disable an interrupt, write to interrupt disable register with the pertinent interrupt bit
set to 1. To check whether an interrupt is enabled or disabled, read interrupt mask register: if the bit is set to 1, the
interrupt is disabled.
37.4.1.6 Transmitting Frames
To set up a frame for transmission:
1. Enable transmit in the network control register.
2. Allocate an area of system memory for transmit data. This does not have to be contiguous, varying byte lengths
can be used as long as they conclude on byte borders.
3. Set-up the transmit buffer list.
4. Set the network control register to enable transmission and enable interrupts.
5. Write data for transmission into these buffers.
6. Write the address to transmit buffer descriptor queue pointer.
7. Write control and length to word one of the transmit buffer descriptor entry.
8. Write to the transmit start bit in the network control register.
37.4.1.7 Receiving Frames
When a frame is received and the receive circuits are enabled, the EMAC checks the address and, in the following
cases, the frame is written to system memory:
if it matches one of the four specific address registers.
if it matches the hash address function.
if it is a broadcast address (0xFFFFFFFFFFFF) and broadcasts are allowed.
if the EMAC is configured to copy all frames.
The register receive buffer queue pointer points to the next entry (see Table 37-1 on page 537) and the EMAC uses this
as the address in system memory to write the frame to. Once the frame has been completely and successfully received
and written to system memory, the EMAC then updates the receive buffer descriptor entry with the reason for the
address match and marks the area as being owned by software. Once this is complete an interrupt receive complete is
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set. Software is then responsible for handling the dat a in the buffer and then releasing the buffer by writing the ownership
bit back to 0.
If the EMAC is unable to write the data at a rate to match the incoming frame, then an interrupt receive overrun is set. If
there is no receive buffer available, i.e., the next buffer is still owned by software, the interrupt receive buffer not available
is set. If the frame is not successfully received, a statistic register is incremented and the frame is discarded without
informing software.
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37.5 Ethernet MAC 10/100 (EMAC) User Interface
Table 37-6. Regist er Mapping
Offset Register Name Access Reset
0x00 Network Control Register EMAC_NCR Read-write 0
0x04 Network Configuration Register EMAC_NCFG Read-write 0x800
0x08 Network Status Register EMAC_NSR Read-only -
0x0C Reserved
0x10 Reserved
0x14 Transmit Status Register EMAC_TSR Read-write 0x0000_0000
0x18 Receive Buffer Queue Pointer Register EMAC_RBQP Read-write 0x0000_0000
0x1C Transmit Buffer Queue Pointer Register EMAC_TBQP Read-w rite 0 x0 000_0000
0x20 Receive S tatus Register EMAC_RSR Read-write 0x0000_0000
0x24 Interrupt Status Register EMAC_ISR Read-write 0x0000_0000
0x28 Interrupt Enable Register EMAC_IER Write-only -
0x2C Interrupt Disable Register EMAC_IDR Write-only -
0x30 Interrupt Mask Register EMAC_IMR Read-only 0x0000_3FFF
0x34 Phy Maintenance Register EMAC_MAN Read-write 0x0000_0000
0x38 Pause Time Register EMAC_PTR Read-write 0x0000_0000
0x3C Pause Frames Received Register EMAC_PFR Read-write 0x0000_0000
0x40 Frames Transmitted Ok Register EMAC_FTO Read-write 0x0000_0000
0x44 Single Collision Frames Register EMAC_SCF Read-write 0x0000_0000
0x48 Multiple Collision Frames Register EMAC_MCF Read-write 0x0000_0000
0x4C Frames Received Ok Register EMAC_FRO Read-w rite 0 x0 000_0000
0x50 Frame Check Sequence Errors Register EMAC_FCSE Read-write 0x0000_0000
0x54 Alignment Errors Register EMAC_ALE Read -write 0x0000_0000
0x58 Deferred Transmission Frames Register EMAC_DTF Read-wri te 0x0000_0000
0x5C Late Collisions Register EMAC_LCOL Read-write 0x0000_0000
0x60 Excessive Collisions Register EMAC_ECOL Read-write 0x0000_0000
0x64 Transmit Underrun Errors Register EMAC_TUND Read-write 0x0000_0000
0x68 Carrier Sense Errors Register EMAC_CSE Read-write 0x0000_0000
0x6C Receive Resource Errors Register EMAC_RRE Read-write 0x0000_0000
0x70 Receive Overrun Errors Register EMAC_ROV Read-write 0x0000_0000
0x74 Receive Symbol Errors Register EMAC_RSE Read-write 0x0000_0000
0x78 Excessive Length Errors Register EMAC_ELE Read-write 0x0000_0000
0x7C Receive Jabbers Register EMAC_RJA Read-write 0x0000_0000
0x80 Undersize Frames Register EMAC_USF Read-write 0x0000_0000
0x84 SQE Test Errors Register EMAC_STE Read-write 0x0000_0000
0x88 Received Length Field Mismatch Register EMAC_RLE Read-write 0x0000_0000
549
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
0x90 Hash Register Bottom [31:0] Register EMAC_HRB Read-write 0x0000_0000
0x94 Hash Register Top [63:32] Register EMAC_HRT Read-wri te 0x0000_0000
0x98 Specific Address 1 Bottom Register EMAC_SA1B Read-write 0x0000_0000
0x9C Specific Address 1 Top Register EMAC_SA1T Read-write 0x0000_0000
0xA0 S pecific Address 2 Bottom Register EMAC_SA2B Read-write 0x0000_0000
0xA4 Specific Address 2 Top Register EMAC_SA2T Read-w rite 0 x0 000_0000
0xA8 Specific Address 3 Bottom Register EMAC_SA3B Read-write 0x0000_0000
0xAC Specific Address 3 Top Register EMAC_SA3T Read-w rite 0 x0 000_0000
0xB0 Specific Address 4 Bottom Register EMAC_SA4B Read-write 0x0000_0000
0xB4 S pecific Address 4 Top Register EMAC_SA4T Read-write 0x0000_0000
0xB8 T ype ID Checking Register EMAC_TID Read-write 0x0000_0000
0xC0 User Input/output Register EMAC_USRIO Read-write 0x0000_0000
0xC8-0xF8 Reserved – – –
0xC8 - 0xFC Reserved – – –
Table 37-6. Regist er Mapping (Continued)
Offset Register Name Access Reset
550
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.1 Network Control Register
Register Name: EMAC_NCR
Access Type: Read-write
• LB: LoopBack
Asserts the loopback signal to the PHY.
• LLB: Loopback Local
Connects txd to rxd, tx_en to rx_dv, forces full duplex and drives rx_clk and tx_clk with pclk divided by 4. rx_clk
and tx_clk may glitch as the EMAC is switched into and out of internal loop back. It is important that receive and transmit cir-
cuits have already been disabled when making the switch into and out of internal loop back.
• RE: Receive Enable
When set, enables the EMAC to receive data. When reset, frame reception stops immediately and the receive FIFO is cleared.
The receive queue pointer register is unaffected.
• TE: Transmit Enable
When set, enables the Ethernet transmitter to send data. When reset transmission, stops immediately, the transmit FIFO and
control registers are cleared and the transmit queue pointer register resets to point to the start of the transmit descriptor list.
• MPE: Management Port Enable
Set to one to enable the management port. When zero, forces MDIO to high impedance state and MDC low.
• CLRSTAT: Clear Statistics Registers
This bit is write only. Writing a one clears the statistics registers.
• INCSTAT: Increment Statistics Registers
This bit is write only. Writing a one increments all the statistics registers by one for test purposes.
• WESTAT: Write Enable for Statistics Regi sters
Setting this bit to one makes the statistics registers writable for functional test purposes.
• BP: Back Pressure
If set in half duplex mode, forces collisions on all received frames.
• TSTART: Start Transmission
Writing one to this bit starts transmission.
• THALT : Transmit Halt
Writing one to this bit halts transmission as soon as any ongoing frame transmission ends.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
–––––THALTTSTARTBP
76543210
WESTAT INCSTAT CLRSTAT MPE TE RE LLB LB
551
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.2 Network Configuration Register
Register Name: EMAC_NCFGR
Access Type: Read-write
• SPD: Speed
Set to 1 to indicate 100 Mbit/s operation, 0 for 10 Mbit/s.
• FD: Full Duplex
If set to 1, the transmit block ignores the state of collision and carrier sense and allows receive while transmitting.
• CAF: Copy All Frames
When set to 1, all valid frames are received.
• JFRAME: Jumbo Fram es
Set to one to enable jumbo frames of up to 10240 bytes to be accepted.
• NBC: No Broadcast
When set to 1, frames addressed to the broadcast address of all ones are not received.
• MTI: Multicast Hash Enable
When set, multicast frames are received when the 6-bit hash function of the destination address points to a bit that is set in the
hash register.
• UNI: Unicast Hash Enable
When set, unicast frames are received when the 6-bit hash function of the destination address points to a bit that is set in the hash
register.
• BIG: Receive 1536 byt es frames
Setting this bit means the EMAC receives frames up to 1536 bytes in length. Normally, the EMAC would reject any frame above
1518 bytes.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––IRXFCSEFRHDDRFCSRLCE
15 14 13 12 11 10 9 8
RBOF PAE RTY CLK BIG
76543210
UNI MTI NBC CAF JFRAME – FD SPD
552
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
• CLK: MDC clock divider
Set according to system clock speed. This determines by what number system clock is divided to generate MDC. For con-
formance with 802.3, MDC must not exceed 2.5MHz (MDC is only active during MDIO read and write operations).
• RTY: Retry test
Must be set to zero for normal operation. If set to one, the back off between collisions is always one slot time. Setting this bit to
one helps testing the too many retries condition. Also used in the pause frame tests to reduce the pause counters decrement time
from 512 bit times, to every rx_clk cycle.
•PAE: Pause Enable
When set, transmission pauses when a valid pause frame is received.
• RBOF: Receive Buffer Offset
Indicates the number of bytes by which the received data is offset from the start of the first receive buffer.
• RLCE: Receive Length field Checking Enable
When set, frames with measured lengths shorter than their length fields are discarded. Frames containing a type ID in bytes 13
and 14 — length/type ID = 0600 — are not be counted as length errors.
• DRFCS: Discard Receive FCS
When set, the FCS field of received frames are not be copied to memory.
• EFRHD:
Enable Frames to be received in half-duplex mode while transmitting.
• IRXFCS: Igno r e RX FCS
When set, frames with FCS/CRC errors are not rejected and no FCS error statistics are counted. For normal operation, this bit
must be set to 0.
CLK MDC
00 MC K divided by 8 (MCK up to 20 MHz)
01 MC K divided by 16 (MCK up to 40 MHz)
10 MC K divided by 32 (MCK up to 80 MHz)
11 MCK divided by 64 (MCK up to 160 MHz)
RBOF Offset
00 No offset from start of receive buffer
01 One- byte offset from start of receive buffer
10 Two-byte offset from start of receive buffer
11 Three-byte offset from start of receive buffer
553
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.3 Network Status Register
Register Name: EMAC_NSR
Access Type: Read-only
•MDIO
Returns status of the MDIO pin. Use the PHY maintenance register for reading managed frames rather than this bit.
•IDLE
0 = The PHY logic is running.
1 = The PHY management logic is idle (i.e., has completed).
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––IDLEMDIO–
554
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.4 Transmit Status Register
Register Name: EMAC_TSR
Access Type: Read-write
This register, when read, provides details of the status of a transmit. Once read, individual bits may be cleared by writing 1 to
them. It is not possible to set a bit to 1 by writing to the register.
• UBR: Used Bit Read
Set when a transmit buffer descriptor is read with its used bit set. Cleared by writing a one to this bit.
• COL: Collision Occurred
Set by the assertion of collision. Cleared by writing a one to this bit.
• RLE: Retry Limit exceeded
Cleared by writing a one to this bit.
• TGO: Tra ns m it Go
If high transmit is active.
• BEX: Buffers exhausted mid frame
If the buffers run out during transmission of a frame, then transmission stops, FCS shall be bad and tx_er asserted. Cleared by
writing a one to this bit.
• COMP: Transmit Complete
Set when a frame has been transmitted. Cleared by writing a one to this bit.
• UND: Transmit Underrun
Set when transmit DMA was not able to read data from memory, either because the bus was not granted in time, because a not
OK hresp(bus error) was returned or because a used bit was read midway through frame transmission. If this occurs, the
transmitter forces bad CRC. Cleared by writing a one to this bit.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
– UND COMP BEX TGO RLE COL UBR
555
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.5 Receive Buffer Queue Pointer Register
Register Name: EMAC_RBQP
Access Type: Read-write
This register points to the entry in the receive bu ffer queue (descrip tor list) currently being used. It is written with the start location
of the receive buffer descriptor list. The lower order bits increment as buffers are used up and wrap to their original values after
either 1024 buffers or when the wrap bit of the entry is set.
Reading this register returns the location of the descriptor currently being accessed. This value increments as buffers are used.
Software should not use this register for determining where to remove received frames from the queue as it constantly changes
as new frames are received. Software should instead work its way through the buffer descriptor queue checking the used bits.
Receive buffer writes also comprise bursts of two words and, as with transmit buffer reads, it is recommended that bit 2 is always
written with zero to prevent a burst crossing a 1K boundary, in violation of section 3.6 of the AMBA specification.
• ADDR: Receive buffer queue pointer address
Written with the address of the start of the receive queue, reads as a pointer to the current buffer being used.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR – –
556
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.6 Transmit Buffer Queue Pointer Register
Register Name: EMAC_TBQP
Access Type: Read-write
This register points to the entry in the transmit buffer queue (descriptor list) currently being used. It is written with the start location
of the transmit buffer descriptor list. The lower order bits increment as buffers are used up and wrap to their original values after
either 1024 buffers or when the wrap bit of the entry is set. This register can only be written when bit 3 in the transmit status reg-
ister is low.
As transmit buffer reads consist of bursts of two words, it is recommended that bit 2 is always written with zero to prevent a burst
crossing a 1K boundary, in violation of section 3.6 of the AMBA specification.
• ADDR: Transmit buffer queue pointer address
Written with the address of the start of the transmit queue, reads as a pointer to the first buffer of the frame being transmitted or
about to be transmitted.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR – –
557
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.7 Receive Status Register
Register Name: EMAC_RSR
Access Type: Read-write
This register, when read, provides details of the status of a receive. Once read, individual bits may be cleared by writing 1 to them.
It is not possible to set a bit to 1 by writing to the register.
• BNA: Buffer Not Available
An attempt was made to get a new buffer and the pointer indicated that it was owned by the processor. The DMA rereads the
pointer each time a new frame starts until a valid pointer is found. This bit is set at each attempt that fails even if it has not had a
successful pointer read since it has been cleared.
Cleared by writing a one to this bit.
• REC: Frame Received
One or more frames have been received and placed in memory. Cleared by writing a one to this bit.
• OVR: Receive Overrun
The DMA block was unable to store the receive frame to memory, either because the bus was not granted in time or because a
not OK hresp(bus error) was returned. The buffer is recovered if this happens.
Cleared by writing a one to this bit.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
–––––OVRRECBNA
558
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.8 Interrupt Status Register
Register Name: EMAC_ISR
Access Type: Read-write
• MFD: Management Frame Done
The PHY maintenance register has completed its operation. Cleared on read.
• RCOMP: Receive Complete
A frame has been stored in memory. Cleared on read.
• RXUBR: Receive Used Bit Read
Set when a receive buffer descriptor is read with its used bit set. Cleared on read.
• TXUBR: Transmit Used Bit Read
Set when a transmit buffer descriptor is read with its used bit set. Cleared on read.
• TUND: Ethernet Transmit Buffer Underrun
The transmit DMA did not fetch frame data in time for it to be transmitted or hresp returned not OK. Also set if a used bit is read
mid-frame or when a new transmit queue pointer is written. Cleared on read.
• RLE: Retry Limit Exceeded
Cleared on read.
• TXERR: Transmit Err or
Transmit buffers exhausted in mid-frame - transmit error. Cleared on read.
• TCOMP: Transmit Complete
Set when a frame has been transmitted. Cleared on read.
• ROVR: Receive Overrun
Set when the receive overrun status bit gets set. Cleared on read.
• HRESP: Hresp not OK
Set when the DMA block sees a bus error. Cleared on read.
• PFR: Pause Frame Received
Indicates a valid pause has been received. Cleared on a read.
• PTZ: Pause Time Zero
Set when the pause time register, 0x38 decrements to zero. Cleared on a read.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
559
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.9 Interrupt Enable Register
Register Name: EMAC_IER
Access Type: Write-only
• MFD: Management Frame sent
Enable management done interrupt.
• RCOMP: Receive Complete
Enable receive complete interrupt.
• RXUBR: Receive Used Bit Read
Enable receive used bit read interrupt.
• TXUBR: Transmit Used Bit Read
Enable transmit used bit read interrupt.
• TUND: Ethernet Transmit Buffer Underrun
Enable transmit underrun interrupt.
• RLE: Retry Limit Exceeded
Enable retry limit exceeded interrupt.
• TXERR
Enable transmit buffers exhausted in mid-frame interrupt.
• TCOMP: Transmit Complete
Enable transmit complete interrupt.
• ROVR: Receive Overrun
Enable receive overrun interrupt.
• HRESP: Hresp not OK
Enable Hresp not OK interrupt.
• PFR: Pause Frame Received
Enable pause frame received interrupt.
• PTZ: Pause Time Zero
Enable pause time zero interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
560
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.10 Interrupt Disable Register
Register Name: EMAC_IDR
Access Type: Write-only
• MFD: Management Frame sent
Disable management done interrupt.
• RCOMP: Receive Complete
Disable receive complete interrupt.
• RXUBR: Receive Used Bit Read
Disable receive used bit read interrupt.
• TXUBR: Transmit Used Bit Read
Disable transmit used bit read interrupt.
• TUND: Ethernet Transmit Buffer Underrun
Disable transmit underrun interrupt.
• RLE: Retry Limit Exceeded
Disable retry limit exceeded interrupt.
• TXERR
Disable transmit buffers exhausted in mid-frame interrupt.
• TCOMP: Transmit Complete
Disable transmit complete interrupt.
• ROVR: Receive Overrun
Disable receive overrun interrupt.
• HRESP: Hresp not OK
Disable Hresp not OK interrupt.
• PFR: Pause Frame Received
Disable pause frame received interrupt.
• PTZ: Pause Time Zero
Disable pause time zero interrupt.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
561
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.11 Interrupt Mask Register
Register Name: EMAC_IMR
Access Type: Read-only
• MFD: Management Frame sent
Management done interrupt masked.
• RCOMP: Receive Complete
Receive complete interrupt masked.
• RXUBR: Receive Used Bit Read
Receive used bit read interrupt masked.
• TXUBR: Transmit Used Bit Read
Transmit used bit read interrupt masked.
• TUND: Ethernet Transmit Buffer Underrun
Transmit underrun interrupt masked.
• RLE: Retry Limit Exceeded
Retry limit exceeded interrupt masked.
• TXERR
Transmit buffers exhausted in mid-frame interrupt masked.
• TCOMP: Transmit Complete
Transmit complete interrupt masked.
• ROVR: Receive Overrun
Receive overrun interrupt masked.
• HRESP: Hresp not OK
Hresp not OK interrupt masked.
• PFR: Pause Frame Received
Pause frame received interrupt masked.
• PTZ: Pause Time Zero
Pause time zero interrupt masked.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
– – PTZ PFR HRESP ROVR –
76543210
TCOMP TXERR RLE TUND TXUBR RXUBR RCOMP MFD
562
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.12 PHY Maintenance Register
Register Name: EMAC_MAN
Access Type: Read-write
•DATA
For a write operation this is written with the data to be written to the PHY.
After a read operation this contains the data read from the PHY.
•CODE:
Must be written to 10. Reads as written.
• REGA: Register Address
Specifies the register in the PHY to access.
• PHYA: PHY Address
• RW: Read-write
10 is read; 01 is write. Any other value is an invalid PHY management frame
• SOF: Start of frame
Must be written 01 for a valid frame.
31 30 29 28 27 26 25 24
SOF RW PHYA
23 22 21 20 19 18 17 16
PHYA REGA CODE
15 14 13 12 11 10 9 8
DATA
76543210
DATA
563
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.13 Pause Time Register
Register Name: EMAC_PTR
Access Type: Read-write
• PTIME: Pause Time
Stores the current value of the pause time register which is decremented every 512 bit times.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
PTIME
76543210
PTIME
564
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.14 Hash Register Bottom
Register Name: EMAC_HRB
Access Type: Read-write
• ADDR:
Bits 31:0 of the hash address register. See “Hash Addressing” on page 542.
37.5.15 Hash Register Top
Register Name: EMAC_HRT
Access Type: Read-write
• ADDR:
Bits 63:32 of the hash address register. See “Hash Addressing” on page 542.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
565
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.16 Specific Address 1 Bottom Register
Register Name: EMAC_SA1B
Access Type: Read-write
• ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corresponds to
the least significant bit of the first byte received.
37.5.17 Specific Address 1 Top Register
Register Name: EMAC_SA1T
Access Type: Read-write
• ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
566
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.18 Specific Address 2 Bottom Register
Register Name: EMAC_SA2B
Access Type: Read-write
• ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corresponds to
the least significant bit of the first byte received.
37.5.19 Specific Address 2 Top Register
Register Name: EMAC_SA2T
Access Type: Read-write
• ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
567
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.20 Specific Address 3 Bottom Register
Register Name: EMAC_SA3B
Access Type: Read-write
• ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corresponds to
the least significant bit of the first byte received.
37.5.21 Specific Address 3 Top Register
Register Name: EMAC_SA3T
Access Type: Read-write
• ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
568
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.22 Specific Address 4 Bottom Register
Register Name: EMAC_SA4B
Access Type: Read-write
• ADDR
Least significant bits of the destination address. Bit zero indicates whether the address is multicast or unicast and corresponds to
the least significant bit of the first byte received.
37.5.23 Specific Address 4 Top Register
Register Name: EMAC_SA4T
Access Type: Read-write
• ADDR
The most significant bits of the destination address, that is bits 47 to 32.
31 30 29 28 27 26 25 24
ADDR
23 22 21 20 19 18 17 16
ADDR
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
ADDR
76543210
ADDR
569
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.24 Type ID Checking Register
Register Name: EMAC_TID
Access Type: Read-write
• TID: Type ID Checking
For use in comparisons with received frames TypeID/Length field.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
TID
76543210
TID
570
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.25 User Input/Output Register
Register Name: EMAC_USRIO
Access Type: Read-write
•RMII
When set, this bit enables the RMII operation mode. When reset, it selects the MII mode.
•CLKEN
When set, this bit enables the transceiver input clock.
Setting this bit to 0 reduces power consumption when the treasurer is not used.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
––––––CLKENRMII
571
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26 EMAC Statistic Registers
These registers reset to zero on a read and stick at all ones when they count to their maximum value. They should be read fre-
quently enough to prevent loss of data. The receive statistics registers are only incremented when the receive enable bit is set in
the network control register. To write to these registers, bit 7 must be set in the network control register. The statistics register
block contains the following registers.
37.5.26.1 Pause Frames Received Register
Register Name: EMAC_PFR
Access Type: Read-write
• FROK: Pause Frames Received OK
A 16-bit register counting the number of good pause frames received. A good frame has a length of 64 to 1518 (1536 if bit 8 set in
network configuration register) and has no FCS, alignment or receive symbol errors.
37.5.26.2 Frames Transmitted OK Register
Register Name: EMAC_FTO
Access Type: Read-write
• FTOK: Frames Transmitted OK
A 24-bit register counting the number of frames successfully transmitted, i.e., no underrun and not too many retries.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
FROK
76543210
FROK
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FTOK
15 14 13 12 11 10 9 8
FTOK
76543210
FTOK
572
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.3 Single Collision Frames Register
Register Name: EMAC_SCF
Access Type: Read-write
• SCF: Single Collision Frames
A 16-bit register counting the number of frames experiencing a single collision before being successfully transmitted, i.e., no
underrun.
37.5.26.4 Multicollision Frames Register
Register Name: EMAC_MCF
Access Type: Read-write
• MCF: Multicollision Frames
A 16-bit register counting the number of frames experiencing between two and fifteen collisions prior to being successfully trans-
mitted, i.e., no underrun and not too many retries.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
SCF
76543210
SCF
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
MCF
76543210
MCF
573
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.5 Frames Received OK Register
Register Name: EMAC_FRO
Access Type: Read-write
• FROK: Frames Received OK
A 24-bit register counting the number of good frames received, i.e., address recognized and successfully copied to memory. A
good frame is of length 64 to 1518 bytes (1536 if bit 8 set in network configuration register) and has no FCS, alignment or receive
symbol errors.
37.5.26.6 Frames Check Sequence Errors Register
Register Name: EMAC_FCSE
Access Type: Read-write
• FCSE: Frame Check Sequence Errors
An 8-bit register counting frames that are an integral number of bytes, have bad CRC and are between 64 and 1518 bytes in
length (1536 if bit 8 set in network configuration register). This register is also incremented if a symbol error is detected and the
frame is of valid length and has an integral number of bytes.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
FROK
15 14 13 12 11 10 9 8
FROK
76543210
FROK
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
FCSE
574
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.7 Alignment Errors Register
Register Name: EMAC_ALE
Access Type: Read-write
• ALE: Alignment Errors
An 8-bit register counting frames that are not an integral number of bytes long and have bad CRC when their length is truncated
to an integral number of bytes and are between 64 and 1518 bytes in length (1536 if bit 8 set in network configuration register).
This register is also incremented if a symbol error is detected and the frame is of valid length and does not have an integral num-
ber of bytes.
37.5.26.8 Deferred Transmission Frames Register
Register Name: EMAC_DTF
Access Type: Read-write
• DTF: Deferred Transmission Frames
A 16-bit register counting the number of frames experiencing deferral due to carrier sense being active on their first attempt at
transmission. Frames involved in any collision are not counted nor are frames that experienced a transmit underrun.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ALE
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
DTF
76543210
DTF
575
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.9 Late Collisions Register
Register Name: EMAC_LCOL
Access Type: Read-write
• LCOL: Late Collisions
An 8-bit register counting the number of frames that experience a collision after the slot time (512 bits) has expired. A late collision
is counted twice; i.e., both as a collision and a late collision.
37.5.26.10Excessive Collisions Register
Register Name: EMAC_EXCOL
Access Type: Read-write
• EXCOL: Excessive Collisions
An 8-bit register counting the number of frames that failed to be transmitted because they experienced 16 collisions.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
LCOL
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
EXCOL
576
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.11Transmit Underrun Errors Register
Register Name: EMAC_TUND
Access Type: Read-write
• TUND: Transmit Underruns
An 8-bit register counting the number of frames not transmitted due to a transmit DMA underrun. If this register is incremented,
then no other statistics register is incremented.
37.5.26.12Carrier Sense Errors Register
Register Name: EMAC_CSE
Access Type: Read-write
• CSE: Carrier Sense Errors
An 8-bit register counting the number of frames transmitted where carrier sense was not seen during transmission or where car-
rier sense was deasserted after being asserted in a transmit frame without collision (no underrun). Only incremented in half-
duplex mode. The only effect of a carrier sense error is to increment this register. The behavior of the other statistics registers is
unaffected by the detection of a carrier sense error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
TUND
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
CSE
577
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.13Receive Resource Errors Register
Register Name: EMAC_RRE
Access Type: Read-write
• RRE: Receive Resource Errors
A 16-bit register counting the number of frames that were address matched but could not be copied to memory because no
receive buffer was available.
37.5.26.14Receive Overrun Errors Register
Register Name: EMAC_ROVR
Access Type: Read-write
• ROVR: Receive Overrun
An 8-bit register counting the number of frames that are address recognized but were not copied to memory due to a receive DMA
overrun.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
RRE
76543210
RRE
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
ROVR
578
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.15Receive Symbol Errors Register
Register Name: EMAC_RSE
Access Type: Read-write
• RSE: Receive Symbol Errors
An 8-bit register counting the number of frames that had rx_er asserted during reception. Receive symbol errors are also
counted as an FCS or alignment error if the frame is between 64 and 1518 bytes in length (1536 if bit 8 is set in the network con-
figuration register). If the frame is larger, it is recorded as a jabber error.
37.5.26.16Excessive Length Errors Register
Register Name: EMAC_ELE
Access Type: Read-write
• EXL: Excessive Length Errors
An 8-bit register counting the number of frames received exceeding 1518 bytes (1536 if bit 8 set in network configuration register)
in length but do not have either a CRC error, an alignment error nor a receive symbol error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RSE
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
EXL
579
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.17Receive Jabbers Register
Register Name: EMAC_RJA
Access Type: Read-write
• RJB: Receive Jabbers
An 8-bit register counting the number of frames received exceeding 1518 bytes (1536 if bit 8 set in network configuration register)
in length and have either a CRC error, an alignment error or a receive symbol error.
37.5.26.18Undersize Frames Register
Register Name: EMAC_USF
Access Type: Read-write
• USF: Unders ize Frames
An 8-bit register counting the number of frames received less than 64 bytes in length but do not have either a CRC error, an align-
ment error or a receive symbol error.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RJB
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
USF
580
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
37.5.26.19SQE Test Errors Register
Register Name: EMAC_STE
Access Type: Read-write
• SQER: SQE Test Errors
An 8-bit register counting the number of frames where ECOL was not asserted within 96 bit times (an interframe gap) of tx_en
being deasserted in half duplex mode.
37.5.26.20Received Length Field Mismatch Register
Register Name: EMAC_RLE
Access Type: Read-write
• RLFM: Receiv e Length Field Mismatch
An 8-bit register counting the number of frames received that have a measured length shorter than that extracted from its length
field. Checking is enabled through bit 16 of the network configuration register. Frames containing a type ID in bytes 13 and 14
(i.e., length/type ID ≥ 0x0600) are not counted as length field errors, neither are excessive length frames.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
SQER
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
––––––––
15 14 13 12 11 10 9 8
––––––––
76543210
RLFM
581
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38. SAM7X512/256/128 Electrical Characteristics
38.1 Absolute Maximum Ratings
Table 38-1. Absolute Maximum Ratings*
Operating Temperature (Industrial).........-40°C to + 85°C*NOTICE: Stresses beyond those listed under “Absolute Maxi-
mum Ratings” may cause permanent damage to
the device. This is a stress rating only and func-
tional operation of the device at these or other con-
ditions beyond those indicated in the operational
sections of this specification is not implied. Expo-
sure to absolute maximum rating conditions for
extended period s may affect device reliability.
Storage Temperature............................-60°C to + 150°C
Voltage on Input Pins
with Respect to Ground...........................-0.3V to + 5.5V
Maximum Operating Voltage
(VDDCORE, and VDDPLL)........................................2.0V
Maximum Operating Voltage
(VDDIO, VDDIN and VDDFLASH)...........................4.0V
Total DC Output Current on all I/O lines
100-lead LQFP package.................... ... ................. 200 mA
582
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.2 DC Characteristics
The following characteristics are applicable to the operating temperature range: TA = -40°C to 85°C, unless otherwise specified.
Note that even during startup, VVDDFLASH must always be superior or equal to VVDDCORE.
Table 38-2. DC Characteristics
Symbol Parameter Conditions Min Typ Max Units
VVDDCORE DC Supply Core 1.65 1.95 V
VVDDPLL DC Supply PLL 1.65 1.95 V
VVDDIO DC Supply I/Os 3.0 3.6 V
VVDDFLASH DC Supply Flash 3.0 3.6 V
VIL Input Low-level Voltage VVDDIO from 3.0V to 3.6V -0.3 0.8 V
VIH Input High-level Voltage VVDDIO from 3.0V to 3.6V 2.0 5.5 V
VOL Output Low-level Voltage IO = 8 mA, VVDDIO from 3.0V to 3.6V 0.4 V
IO = 0.3 mA, (CMOS) VVDDIO from 3.0V to 3.6V 0.1 V
VOH Output High-level Voltage IO = 8 mA, VVDDIO from 3.0V to 3.6V VDDIO - 0.4 V
IO = 0.3 mA, (CMOS) VVDDIO from 3.0V to 3.6V
V
DDIO
- 0.1
V
ILEAK Input Leakage Current
PA0-PA3, Pull-up resi stors disabled
(Typ: TA = 25°C, Max: TA = 85°C) 40 400 nA
Other PIOs and NRST, Pull-up resistors disabled
(Typ: TA = 25°C, Max: TA = 85°C) 20 200 nA
IPULLUP Input Pull-up Current
PB27-PB30, VVDDIO from 3.0V to 3.6V,
PAx connected to ground 10 20.6 60 µA
Other PIOs and NRST, VVDDIO from 3.0V to 3.6V,
PAx connected to ground 143 321 600 µA
IPULLDOWN Input Pull-down Current,
(TST, ERASE, JTAGSEL) VVDDIO from 3.0V to 3.6V,
Pins connected to VVDDIO 135 295 550 µA
CIN Input Capacitance 100 LQFP Package 13.9 pF
ISC
Static Current
(SAM7X512/256/128)
On VVDDCORE = 1.85V,
MCK = 500Hz TA = 25°C 12 60
µA
All inputs driven at 1
(including TMS, TDI, TCK, NRST)
Flash in standby mode
All peripherals off
TA = 85°C 100 400
IOOutput Current
PA0-PA3, VVDDIO from 3.0V to 3.6V 16 mA
PB27-PB30 and NRST, VVDDIO from 3.0V to 3.6V 2 mA
Other PIOs, VVDDIO from 3.0V to 3.6V 8 mA
TSLOPE Supply Core Slope 6 V/ms
Table 38-3. 1.8V Voltage Regu lator Characteristics
Symbol Parameter Conditions Min Typ Max Units
VVDDIN Supply Voltage 3.0 3.3 3.6 V
VVDDOUT Output Voltage IO = 20 mA 1.81 1.85 1.89 V
583
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
IVDDIN Current consumption After startup, no load 90 µA
After startup, Idle mode, no load 10 25 µA
TSTART Startup Time Cload = 2.2 µF, after VDDIN > 2.7V 150 µS
IOMaximum DC Output Current VDDIN = 3.3V 100 mA
IOMaximum DC Output Current VDDIN = 3.3V, in Idle Mode 1 mA
Table 38-3. 1.8V Voltage Regu lator Characteristics
Table 38-4. Brownout Detecto r Characteristics
Symbol Parameter Conditions Min Typ Max Units
VBOT18- VDDCORE Threshold Level 1.65 1.68 1.71 V
VHYST18 VDDCORE Hysteresis VHYST18 = VBOT18+ - VBOT18- 50 65 mV
VBOT33- VDDFLASH Threshold Level 2.70 2.80 2.90 V
VHYST33 VDDFLASH Hysteresis VHYST33 = VBOT33+ - VBOT33- 70 120 mV
IDD Current Consumption BOD on (GPNVM0 bit active) 24 30 µA
BOD off (GPNVM0 bit inactive) 1 µA
TSTART Startu p Time 100 200 µs
Table 38-5. DC Flash Characteristics SAM7X512/25 6/128
Symbol Parameter Conditions Min Max Units
TPU Power-up de l a y 45 µS
ISB Standby current
@25°C
onto VDDCORE = 1.8V
onto VDDFLAS H = 3.3V 10
30 µA
@85°C
onto VDDCORE = 1.8V
onto VDDFLAS H = 3.3V 10
120 µA
ICC Active current
Random Read @ 30MHz
onto VDDCORE = 1.8V
onto VDDFLAS H = 3.3V 3.0
0.8 mA
Write (one bank for SAMX512)
onto VDDCORE = 1.8V
onto VDDFLAS H = 3.3V 400
5.5 µA
mA
584
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.3 Power Consumption
Typical power consumption of PLLs, Slow Clock and Main Oscillator.
Power consumption of power supply in two different modes: Active and ultra Low-power.
Power consumption by peripheral: calculated as the difference in current measurement after having enabled then
disabled the corresponding clock.
38.3.1 Power Consumption Versus Modes
The values in Table 38-6 and Table 38-7 on page 585 are measured values of the power consumption with operating
conditions as follows:
VDDIO = VDDIN = VDDFLASH= 3.3V
VDDCORE = VDDPLL = 1.85V
TA = 25°C
There is no consumption on the I/Os of the device
Figure 38-1. Measure Schematics
1.8V
VDDIN
Voltage
Regulator
VDDOUT
VDDCORE
VDDPLL
3.3V
VDDIO
VDDFLASH
AMP1
AMP2
585
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
These figures represent the power consumption typically measured on the power supplies..
Notes: 1. “Flash is in standby mode”, means the Flash is not accessed at all.
2. Low power consumption figures stated above cannot be guaranteed when accesing the Flash in Ultra Low
Power mode. In order to meet given low power consumption figures, it is recommended to either stop the
processor or jump to SRAM.
38.3.2 Peripheral Power Consumption in Active Mode
Note: 1. Note: VDDCORE = 1.85V, TA = 25°C
Tabl e 38-6. Power Consumption for Different Modes
Mode Conditions Consumption Unit
Active
(SAM7X512/256/128)
Voltage regulator is on.
Brown Out Detector is activated.
Flash is read.
ARM Core clock is 50MHz.
Analog-to-Digital Converter activated.
All peripheral clocks activated.
USB transceiver enabled.
onto AMP1
onto AMP2 44
43 mA
Ultra Low Power(2)
Voltage regulator is in Low-power mode.
Brown Out Detector is de-activated.
Flash is in standby mode.(1)
ARM Core in idle mode.
MCK @ 500Hz.
Analog-to-Digital Converter de-activated.
All peripheral clocks de-activated.
USB transceiver disabled.
DDM and DDP pins connected to ground.
onto AMP1
onto AMP2 26
12 µA
Table 38-7. Power Consumption on VDDCORE(1)
Peripheral Consumption (Typ) Unit
PIO Controller 12
µA/MHz
USART 28
UDP 20
PWM 16
TWI 5
SPI 16
SSC 32
Timer Counter Channels 6
CAN 75
ARM7TDMI 160
EMAC 120
System Peripherals (SAM7X512/256/128) 200
586
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.4 Crystal Oscillators Characteristics
38.4.1 RC Oscillator Characteristics
Table 38-8. RC Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
1/(tCPRC) RC Oscillator Frequency VDDPLL = 1.65V 22 32 42 kHz
Duty Cycle 45 50 55 %
tST Startup Time VDDPLL = 1.65V 75 µs
IOSC Current Consumption After Startup Time 1.9 µA
587
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.4.2 Main Oscillator Characteristics
Notes: 1. CS is the shunt capacitance.
2. RS = 100-200 Ω; CSHUNT = 2.0 - 2.5 pF; CM = 2 – 1.5 fF (typ, worst case) using 1 K ohm serial resistor on xout.
3. RS = 50-100 Ω; CSHUNT = 2.0 - 2.5 pF; CM = 4 - 3 fF (typ, worst case).
4. RS = 25-50 Ω; CSHUNT = 2.5 - 3.0 pF; CM = 7 -5 fF (typ, worst case).
5. RS = 20-50 Ω; CSHUNT = 3.2 - 4.0 pF; CM = 10 - 8 fF (typ, worst case).
6. CL and CLEXT →
Table 38-9. Main Oscillator Characteristics
Symbol Parameter Conditions Min Typ Max Unit
1/(tCPMAIN) Crystal Oscillator Frequency 3 16 20 MHz
CL1, CL2 Internal Load Capacitance (CL1 = CL2)Integrated Load Capacitance
((XIN or XOUT)) 34 40 46 pF
CL (6) Equivalent Load Capacitance Integrated Load Capacitance
(XIN and XOUT in series) 17 20 23 pF
Duty Cycle 30 50 70 %
tST Startup Time
VDDPLL = 1.2 to 2V
CS = 3 pF(1) 1/(tCPMAIN) = 3 MHz
CS = 7 pF(1) 1/(tCPMAIN) = 16 MHz
CS = 7 pF(1) 1/(tCPMAIN) = 20 MHz
14.5
1.4
1
ms
IDDST Standby Current Consumption Standby mode 1 µA
PON Drive level
@3 MHz
@8 MHz
@16 MHz
@20 MHz
15
30
50
50
µΩ
IDD ON Current dissipation
@3 MHz (2)
@8 MHz (3)
@16 MHz (4)
@20 MHz (5)
150
150
300
400
250
250
450
550
µA
CLEXT (6) Maximum external capacitor
on XIN and XOUT 10 pF
XIN XOUT
CLEXT
CL
CLEXT
AT91SAM7X
588
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.4.3 Crystal Characteristics
38.4.4 XIN Clock Characteristics
Note: 1. These characteristics apply only when the Main Oscillator is in bypass mode (i.e., when MOSCEN = 0 and OSCBYPASS = 1
in the CKGR_MOR register, see the Clock Generator Main Oscillator Register.
Figure 38-2. XIN CLock Timing
Table 38-10 . Crystal Characteristics
Symbol Parameter Conditions Min Typ Max Unit
ESR Equivalent Series Resistor Rs
Fundamental @3 MHz
Fundamental @8 MHz
Fundamental @16 MHz
Fundamental @20 MHz
200
100
80
50
Ω
CMMotional capacitance 8fF
CSHUNT Shunt capacit ance 7pF
Table 38-11. XIN Clock Ele ctrical Characteristics
Symbol Parameter Conditions Min Max Units
1/(tCPXIN) XIN Clock Frequency (1) 50.0 MHz
tCPXIN XIN Clock Period (1) 20.0 ns
tCHXIN XIN Clock High Half-period (1) 8.0 ns
tCLXIN XIN Clock Low Half-period (1) 8.0 ns
tCLCH Rise Time (1) 400
tCHCL Fall Time (1) 400
CIN XIN Input Capacitance (1) 46 pF
RIN XIN Pull-down Resistor (1) 500 kΩ
VXIN_IL VXIN Input Low-level Voltage (1) -0.3 0.2 x VDDPLL V
VXIN_IH VXIN Input High-level Vo ltage (1) 0.8 x VDDPLL 1.95 V
IDDBP Bypass Current Consumption (1) 15 µΩ/MHz
t
CPXIN
t
CPXIN
t
CPXIN
t
CHXIN
t
CLCH
t
CHCL
V
XIN_IL
V
XIN_IH
589
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.5 PLL Characteristics
Note: Startup time depends on PLL RC filter. A calculation tool is provided by Atmel.
Table 38-12. Phase Lock Loop Characteristics
Symbol Parameter Conditions Min Typ Max Unit
FOUT Output Frequency Field out of CKGR_PLL is: 00 80 160 MHz
10 150 200 MHz
FIN Input Frequency 1 32 MHz
IPLL Current Consumption Active mode 4 mA
Standby mode 1 µA
590
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.6 USB Transceiver Characteristics
38.6.1 Electrical Characteristics
38.6.2 Switching Characteristics
Table 38-13 . Electrical Parameters
Symbol Parameter Conditions Min Typ Max Unit
Input Levels
VIL Low Level 0.8 V
VIH High Level 2.0 V
VDI Differential Input Sensitivity |(D+) - (D-)| 0.2 V
VCM Differential Input Common
Mode Range 0.8 2.5 V
CIN Transceiver capacitance Capacitance to ground on each line 9.18 pF
I Hi-Z State Data Line Leakage 0V < VIN < 3.3V -10 +10 µA
REXT Recommended External USB
Series Resistor In series with each USB pin with ±5% 27 Ω
Output Levels
VOL Low Level Output Measured with RL of 1.425 kOhm tied
to 3.6V 0.0 0.3 V
VOH High Level Output Measured with RL of 14.25 kOhm tied
to GND 2.8 3.6 V
VCRS Output Signal Crossover
Voltage Measure conditions described in
Figure 38-3 1.3 2.0 V
Consumption
IVDDIO Current Consumption Transceiver enabled in input mode
DDP=1 and DDM=0 105 200 µA
IVDDCORE Current Consumption 80 150 µA
Table 38-14. In Full Speed
Symbol Parameter Conditions Min Typ Max Unit
tFR Transition Rise Time CLOAD = 50 pF 4 20 ns
tFE Transition Fall Tim e CLOAD = 50 pF 4 2 0 ns
tFRFM Rise/Fall time Matching 90 111.11 %
591
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 38-3. USB Data Signal Rise and Fall Times
10% 10%
90%
VCRS
tRtF
Differential
Data Lines
Rise Time Fall Time
Fosc = 6MHz/750kHz REXT=27 ohms
Cload
Buffer
(b)
(a)
592
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.7 ADC Characteristics
Notes: 1. Corresponds to 13 clock cycles at 5 MHz: 3 clock cycles for track and hold acquisition time and 10 clock cycles for
conversion.
2. Corresponds to 15 clock cycles at 8 MHz: 5 clock cycles for track and hold acquisition time and 10 clock cycles for
conversion.
The user can drive ADC input with impedance up to:
ZOUT ≤ (SHTIM -470) x 10 in 8-bit resolution mode
ZOUT ≤ (SHTIM -589) x 7.69 in 10-bit resolution mode
with SHTIM (Sample and Hold Time register) expressed in ns and ZOUT expressed in ohms.
For more information on data converter terminology, please refer to the application note: Data Converter Terminology,
Atmel lit° 6022.
Table 38-15. Channel Conversion Time and ADC Clock
Parameter Conditions Min Typ Max Units
ADC Clock Frequency 10-bit resolution mode 5 MHz
ADC Clock Frequency 8-bit resolution mode 8 MHz
Startup Time Return from Idle Mode 20 µs
Tr ack and Hold Acquisition Time 600 ns
Conversion Time ADC Clock = 5 MHz 2 µs
Conversion Time ADC Clock = 8 MHz 1.25 µs
Throughput Rate ADC Clock = 5 MHz 384(1) kSPS
Throughput Rate ADC Clock = 8 MHz 533(2) kSPS
Table 38-16 . External Voltage Reference Input
Parameter Conditions Min Typ Max Units
ADVREF Input Voltage Range 2.6 VDDIN V
ADVREF Input Voltage Range 8-bit resolution mode 2.5 VDDIN V
ADVREF Average Current On 13 samples with ADC Clock = 5 MHz 200 250 µA
Current Consumption on VDDIN 0.55 1 mA
Table 38-17. Analog Inputs
Parameter Min Typ Max Units
Input Voltage Range 0V
ADVREF
Input Leakage Current 1µA
Input Capacitance 12 14 pF
Table 38-18. Transfer Characteristics
Parameter Conditions Min Typ Max Units
Resolution 10 Bit
Integral Non-linearity ±2 LSB
Differential Non-linearity No missing code ±1 LSB
Offset Error ±2 LSB
Gain Error ±2 LSB
Absolute Accuracy ±4 LSB
593
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.8 AC Characteristics
38.8.1 Master Clock Characteristics
38.8.2 I/O Characteristics
Criteria used to define the maximum frequency of the I/Os:
output duty cycle (30%-70%)
minimum outp ut swing : 10 0m V to VDDIO - 100mV
Addition of rising and falling time inferior to 75% of the period
Notes: 1. Pin Group 1 = PB27 to PB30
2. Pin Group 2 = PA4 to PA30 and PB0 to PB30
3. Pin Group 3 = PA0 to PA3
4. VVDDIO from 3.0V to 3.6V, maximum external capacitor = 40pF
5. VVDDIO from 3.0V to 3.6V, maximum external capacitor = 20pF
Table 38-19. Master Clock Waveform Parameters
Symbol Parameter Conditions Min Max Units
1/(tCPMCK) Master Clock Frequency 55 MHz
Table 38-20. I/O Characteristics
Symbol Parameter Conditions Min Max Units
FreqMaxI01 Pin Group 1 (1) frequency Load: 40 pF(4) 12.5 MHz
PulseminHI01 Pin Group 1 (1) High Level Pul se Width Load: 40 pF(4) 40 ns
PulseminLI01 Pin Group 1 (1) Low Level Pulse Width Load: 40 pF(4) 40 ns
FreqMaxI02 Pin Group 2 (2) frequen cy Load: 40 pF(4) 25 MHz
Load: 20 pF(5) 30 MHz
PulseminHI02 Pin Group 2 (2) High Level Pulse Width Load: 40 pF(4) 20 ns
Load: 20 pF(5) 10 ns
PulseminLI02 Pin Group 2 (2) Low Level Pulse Width Load: 40 pF(4) 20 ns
Load: 20 pF(5) 10 ns
FreqMaxI03 Pin Group 3 (3) frequency Load: 40 pF(4) 30 MHz
PulseminHI03 Pin Group 3 (3) High Level Pul se Wi dth Load: 40 pF (4) 16.6 ns
PulseminLI03 Pin Group 3 (3) Low Level Pulse Width Load: 40 pF(4) 16.6 ns
594
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.8.3 SPI Characteristics
Figure 38-4. SPI Master mode with (CPOL = NCPHA = 0) or (CPOL= NCPHA= 1)
Figure 38-5. SPI Master mode with (CPOL=0 and NCPHA=1) or (CPOL=1 and NCPHA=0)
Figure 38-6. SPI Slave mode with (CPOL=0 and NCPHA=1) or (CPOL= 1 and NCPHA=0)
SPCK
MISO
MOSI
SPI2
SPI0SPI1
SPCK
MISO
MOSI
SPI5
SPI3SPI4
SPCK
MISO
MOSI
SPI6
SPI7SPI8
595
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 38-7. SPI Slave mode with (CPOL = NCPHA = 0) or (CPOL= NCPHA= 1)
Notes: 1. 3.3V domain: VVDDIO from 3.0V to 3.6V, maximum external capacitor = 40 pF.
2. tCPMCK: Master Clock period in ns.
Note that in SPI master mode the ATSAM7X512/256/128 does not sample the data (MISO) on the opposite edge where
data clocks out (MOSI) but the same edge is used as shown in Figure 38-4 and Figure 38-5.
SPCK
MISO
MOSI
SPI9
SPI10 SPI11
Table 38-21. SPI Timings
Symbol Parameter Conditions Min Max Units
SPI0MISO Setup time before SPCK rises (master) 3.3V domain(1) 28.5 + (tCPMCK)/2(2) ns
SPI1MISO Hold time after SPCK rises (master) 3.3V domain(1) 0ns
SPI2SPCK rising to MOSI Delay (master) 3.3V domain(1) 2ns
SPI3MISO Setup time before SPCK falls (master) 3.3V domain(1) 26.5 + (tCPMCK)/2(2) ns
SPI4MISO Hold time after SPCK falls (master) 3.3V domain (1) 0ns
SPI5SPCK falling to MOSI Delay (master) 3 .3V domain (1) 2ns
SPI6SPCK falling to MISO Delay (slave) 3.3V domain (1) 28 ns
SPI7MOSI Setup time before SPCK rises (slave) 3.3V domain (1) 2ns
SPI8MOSI Hold time after SPCK rises (slave) 3.3V domain (1) 3ns
SPI9SPCK rising to MISO Delay (slave) 3.3V domain (1) 28 ns
SPI10 MOSI Setup time before SPCK falls (slave) 3.3V domain (1) 3ns
SPI11 MOSI Hold time after SPCK falls (slave) 3.3V domain (1) 3ns
596
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.8.4 EMAC Characteristics
Notes: 1. f: MCK frequency (MHz)
2. VVDDIO from 3.0V to 3.6V, maximum external capacitor = 20 pF
Note: 1. VVDDIO from 3.0V to 3.6V, maximum exter nal capacitor = 20 pF
Table 38-22. EMAC Signals
Symbol Parameter Conditions Min (ns) Max (ns)
EMAC1Setup for EMDIO from EMDC rising Load: 20pF(2) 2
EMAC2Hold for EMDIO from EMDC rising Load: 20pF(2) ((1/f)-19) + 4(1)
EMAC3EMDIO toggling from EMDC falling Load: 20pF(2) 4.5
Table 38-23. EMAC MII Specific Signals
Symbol Parameter Conditions Min (ns) Max (ns)
EMAC4Setup for ECOL from ETXCK rising Load: 20pF (1) 0
EMAC5Hold for ECOL from ETXCK rising Load: 20pF (1) 2
EMAC6Setup for ECRS from ETXCK rising Load: 20pF (1) 1.5
EMAC7Hold for ECRS from ETXCK rising Load: 20pF (1) 2
EMAC8ETXER toggling from ETXCK rising Load: 20pF (1) 25
EMAC9ETXEN toggling from ETXCK rising Load: 20pF (1) 25
EMAC10 ETX toggling from ETXCK rising Load: 20p F (1) 25
EMAC11 Setup for ERX from ERXCK Load: 20pF (1) 0
EMAC12 Hold for ERX from ERXCK Load: 20pF (1) 4
EMAC13 Setup for ERXER from ERXCK Load: 20pF (1) 0
EMAC14 Hold for ERXER from ERXCK Load: 20pF (1) 4
EMAC15 Setup for ERXDV from ERXCK L oad: 20pF (1) 2
EMAC16 Hold for ERXDV from ERXCK Load: 20pF (1) 2
597
SAM7X Series [DATASHEET]
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Figure 38-8. EMAC MII Mode
EMDC
EMDIO
ECOL
ECRS
ETXCK
ETXER
ETXEN
ETX[3:0]
ERXCK
ERX[3:0]
ERXER
ERXDV
EMAC3
EMAC1EMAC2
EMAC4EMAC5
EMAC6EMAC7
EMAC8
EMAC9
EMAC10
EMAC11 EMAC12
EMAC13 EMAC14
EMAC15 EMAC16
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SAM7X Series [DATASHEET]
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Figure 38-9. EMAC RMII Mode
Table 38-24. EMAC RMII Specific Signals (Only for SAM7X512)
Symbol Parameter Min (ns) Max (ns)
EMAC21 ETXEN toggling from EREFCK rising 4.9 14.2
EMAC22 ETX toggling from EREFCK rising 4.4 15.9
EMAC23 Setup for ERX from EREFCK 0.5
EMAC24 Hold for ERX from EREFCK 0
EMAC25 Setup for ERXER from EREFCK 1.5
EMAC26 Hold for ERXER from EREFCK 0
EMAC27 Setup for ECRSDV from EREFCK 2
EMAC28 Hold for ECRSDV from EREFCK 0
EREFCK
ETXEN
ETX[1:0]
ERX[1:0]
ERXER
ECRSDV
EMAC21
EMAC22
EMAC23 EMAC24
EMAC25 EMAC26
EMAC27 EMAC28
599
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.8.5 Embedded Flash Characteristics
The maximum operating frequency is given in Table 38-25 but is limited by the Embedded Flash access time when the pro cessor
is fetching code out of it. Table 38-25 gives the device maximum operating frequency depending on the field FWS of the
MC_FMR register. This field defines the number of wait states required to access the Embedded Flash Memory.
Table 38-25 . Embedded Flash Wait States
FWS Read Operations Maximum Operating Frequency (MHz)
0 1 cycle 30
1 2 cycles 55
2 3 cycles 55
3 4 cycles 55
Table 38-26. AC Flash Characteristics
Parameter Conditions Min Max Units
Program Cycle Time per page including auto-erase 6 ms
per page without auto-erase 3 ms
Full Chip Erase 15 ms
600
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
38.8.6 JTAG/ICE Timings
38.8.6.1 ICE Interface Signals
Note: 1. VVDDIO from 3.0V to 3.6V, maximum external capacitor = 40pF
Figure 38-10. ICE Interface Signals
Table 38-27. ICE Interface Timing Specification
Symbol Parameter Conditions Min Max Units
ICE0TCK Low Half-period (1) 51 ns
ICE1TCK High Half-period (1) 51 ns
ICE2TCK Period (1) 102 ns
ICE3TDI, TMS, Setup before TCK High (1) 0ns
ICE4TDI, TMS, Hold after TCK High (1) 3ns
ICE5TDO Hold Time (1) 13 ns
ICE6TCK Low to TDO Valid (1) 20 ns
TCK
ICE
3
ICE
4
ICE
6
TMS/TDI
TDO
ICE
5
ICE
1
ICE
2
ICE
0
601
SAM7X Series [DATASHEET]
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38.8.6.2 JTAG Interface Signals
Note: 1. VVDDIO from 3.0V to 3.6V, maximum external capacitor = 40pF
Figure 38-11. JTAG Interface Signals
Table 38-28. JTAG Interface Timing specification
Symbol Parameter Conditions Min Max Units
JTAG0TCK Low Half-period (1) 6.5 ns
JTAG1TCK High Half-period (1) 5.5 ns
JTAG2TCK Period (1) 12 ns
JTAG3TDI, TMS Setup before TCK High (1) 2ns
JTAG4TDI, TMS Hold after TCK High (1) 3ns
JTAG5TDO Hold Time (1) 4ns
JTAG6TCK Low to TDO Valid (1) 16 ns
JTAG7Device Inputs Setup Time (1) 0ns
JTAG8Device Inputs Hold Time (1) 3ns
JTAG9Device Outputs Hold Time (1) 6ns
JTAG10 TCK to Device Outputs Valid (1) 18 ns
TCK
JTAG9
TMS/TDI
TDO
Device
Outputs
JTAG5
JTAG4
JTAG3
JTAG0JTAG1
JTAG2
JTAG10
Device
Inputs
JTAG8
JTAG7
JTAG6
602
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
39. SAM7X512/256/128 Mechanical Characteristics
39.1 Package Drawings
Figure 39-1. LQFP Package Drawing
603
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Table 39-1. 100-lead LQFP Package Dimensions
Symbol Millimeter Inch
Min Nom Max Min Nom Max
A 1.60 0.063
A1 0.05 0.15 0.002 0.006
A2 1.35 1.40 1.45 0.053 0.055 0.057
D 16.00 BSC 0.630 BSC
D1 14.00 BSC 0.551 BSC
E 16.00 BSC 0.630 BSC
E1 14.00 BSC 0.551 BSC
R2 0.08 0.20 0.003 0.008
R1 0.08 0.003
Q0°3.5°7°0°3.5°7°
θ10°0°
θ211°12°13°11°12°13°
θ311°12°13°11°12°13°
c 0.09 0.20 0.004 0.008
L 0.45 0.60 0.75 0.018 0.024 0.030
L1 1.00 REF 0.039 REF
S 0.20 0.008
b 0.17 0.20 0.27 0.007 0.008 0.011
e 0.50 BSC 0.020 BSC
D2 12.00 0.472
E2 12.00 0.472
Tolerances of Form and Position
aaa 0.20 0.008
bbb 0.20 0.008
ccc 0.08 0.003
ddd 0.08 0.003
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SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 39-2. 100-TFBGA Package Drawing
This package respects the recommendations of the NEMI User Group.
All dimensions are in mm
Table 39-2. Device and LQFP Package Maximum Weight
SAM7X512/256/128 800 mg
Table 39-3. Package Reference
JEDEC Drawing Reference MS-026
JESD97 Classification e3
Table 39-4. LQFP Package Characteristics
Moisture Sensitivity Level 3
605
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
39.2 Soldering Profile
Table 39-5 gives the recommended soldering profile from J-STD-020C.
Note: The package is certified to be backward compatible with Pb/Sn soldering profile.
A maximum of three reflow passes is allowed per component.
Table 39-5. Soldering Profile
Profile Feature Green Package
Average Ramp-up Rate (217°C to Peak) 3°C/sec. max.
Preheat Temperature 175°C ±25°C 180 sec. max.
Temperature Maintained Above 217°C 60 sec. to 150 sec.
Time within 5°C of Actual Peak Temperature 20 sec. to 40 sec.
Peak Temperature Range 260°C
Ramp-down Rate 6°C/sec. max.
Time 25°C to Peak Temperature 8 min. max.
606
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
40. AT91SAM7X Ordering Information
Note: 1. Packing type is tape and reel.
Table 40-1. Ordering Information
MRL A
Orderin g Co de MRL B
Ordering Code MRL C
Ordering Code Package Package
Type Temperature
Operating Range
AT91SAM7X512-AU
–
AT91SAM7X512-CU
AT91SAM7X512B-AU
AT91SAM7X512B-AUR
AT91SAM7X512B-CU –LQFP 100
LQFP 100(1)
TFBGA 100 Green Industrial
(-40°C to 85°C)
AT91SAM7X256-AU
AT91SAM7X256-CU AT91SAM7X256B-AU
AT91SAM7X256B-CU AT91SAM7X256C-AU
AT91SAM7X256C-CU LQFP 100
TFBGA 100 Green Industrial
(-40°C to 85°C)
AT91SAM7X128-AU
AT91SAM7X128-CU AT91SAM7X128B-AU
AT91SAM7X128B-CU AT91SAM7X128C-AU
AT91SAM7X128C-CU LQFP 100
TFBGA 100 Green Industrial
(-40°C to 85°C)
607
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
41. SAM7X512/256/128 Errata
41.1 Marking
All devices are marked with the Atmel logo and the ordering code.
Additional marking has the following format:
where
“YY”: manufactory year
“WW”: manufactory week
“V”: revision
“XXXXXXXXX”: lot number
YYWW V
XXXXXXXXX ARM
608
SAM7X Series [DATASHEET]
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41.2 Errata Summary by Product and Revision or Manufacturing Number
Table 41-1 . Errata Summary Table
SAM7Xx Product
Revision or Manufacturing Number
Errata
SAM7X512 rev A
SAM7X512 rev B
SAM7X256/128 rev A
SAM7X256/128 rev B
SAM7X256/128 rev C
Part
Boundary
Scan BSDL File for Rev. B Devices Not Compatible with Rev. C
Devices ––––X
ADC DRDY Bit Cleared XXXX–
ADC DRDY not Cleared on Disable XXXX–
ADC DRDY Possibly Skipped due to CDR Read XXXX–
ADC Possible Skip on DRDY when Disabling a Channel XXXX–
ADC GOVRE Bit is not Updated XXXX–
ADC GOVRE Bit is not Set when Reading CDR XXXX–
ADC GOVRE Bit is not Set when Disabling a Channel XXXX–
ADC O VRE Flag Behavior XXXX–
ADC E OC Set although Channel Disabled XXXX–
ADC Spurious Clear of EOC Flag XXXX–
ADC Sleep Mode XXXX–
CAN Low Power Mode and Error Frame XXXX–
CAN Low Power Mode and Pending Transmit Messages XXXX–
EFC1 Embedded Flash Access Time 1 X––––
EFC2 Embedded Flash Access Time 2 –X––X
EMAC RMII Mode ––XX–
EMAC Possible Event Loss when Reading EMAC_ISR XXXXX
EMAC Possible Event Loss when Reading the Statistics Register Block XXXXX
PIO Leakage on PB27 - PB30 XXX––
PIO Electrical Characteristics on NRST and PA0-PA30 and PB0 -
PB26 XXXXX
PIO Drive Low NRST, PA0-PA30 and PB0-PB26 XXXXX
PWM Update when PWM_CCNTx = 0 or 1 XXXXX
PWM Update when PWM_CPRDx = 0 XXXXX
PWM Counter Start Value XXXXX
PWM Behavior of CHIDx Status Bits in the PWM_SR Register XXXX–
RTT Possible Event Loss when Reading RTT_SR XXXXX
SPI Software Reset Must be Written Twice XX–X–
SPI Bad Behavior when CSAAT = 1 and SCBR = 1 XXXX–
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SAM7X Series [DATASHEET]
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SPI LASTXFER (Last Transfer) behavior XXXX–
SPI SPCK Behavior in Master Mode XXXX–
SPI Chip Select and Fixed Mode XXXX–
SPI Baudrate Set to 1 XXXX–
SPI Bad Serial Clock Generation on 2nd Chip Select XXXXX
SSC Periodic Transmission Limitations in Master Mode XXXX–
SSC Transmitter Limitations in Slave Mode XXXX–
SSC Transmitter Limitations in Slave Mode XXXX–
TWI Clock Divider XXXX–
TWI Software Reset XXXX–
TWI Disabling Does not Operate Correctly XXXX–
TWI NACK Status Bit Lost XXXX–
TWI Possible Receive Holding Register Corruption XXXX–
USART CTS in Hardware Handshaking XXXX–
USART Hardware Handshaking – Two Characters Sent XXXX–
USART RXBRK Flag Error in Asynchronous Mode XXXX–
USART DCD is active High instead of Low XXXXX
Table 41-1. Errata Summary Table (Continued)
SAM7Xx Product
Revision or Manufacturing Number
Errata
SAM7X512 rev A
SAM7X512 rev B
SAM7X256/128 rev A
SAM7X256/128 rev B
SAM7X256/128 rev C
Part
610
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
41.3 AT91SAM7X256/128 Errata - Rev. A Part s
Refer to Section 41.1 “Marking” on page 607.
Note: AT91SAM7X256 Revision A chip ID is 0x275B 0940.
AT91SAM7X128 Revision A chip ID is 0x275A 0740.
41.3.1 Analog-to-Digital Converter (ADC)
41.3.1.1 ADC: DRDY Bit Cleared
The DRDY Flag should be clear only after a read of ADC_LCDR (Last Converted Data Register). A read of any
ADC_CDRx register (Channel Data Register) automatically clears the DRDY flag.
Problem Fix/Workaround:
None
41.3.1.2 ADC: DRDY not Cleared on Disable
When reading LCDR at the same instant as an end of conversion, with DRDY already active, DRDY is kept active
regardless of the enable status of the current channel. This sets DRDY, whereas new data is not stored.
Problem Fix/Workaround
None
41.3.1.3 ADC: DRDY Possibly Skipped due to CDR Read
Reading CDR for channel "y" at the same instant as an end of conversion on channel "x" with EOC[x] already active,
leads to skipping to set the DRDY flag if channel "x" is enabled.
Problem Fix/Workaround
Use of DRDY functionality with access to CDR registers should be avoided.
41.3.1.4 ADC: Possible Skip on DRDY when Disabling a Channel
DRDY does not rise when disabling channel "y" at the same time as an end of "x" channel conversion, although data is
stored into CDRx and LCDR.
Problem Fix/Workaround
None.
41.3.1.5 ADC: GOVRE Bit is not Updated
Read of the Status Register at the same instant as an end of conversion leads to skipping the update of the GOVRE
(general overrun) flag. GOVRE is neither reset nor set.
For example, if reading the status while an end of conversion is occurring and:
1. GOVRE is active but DRDY is inactive, does not correspond to a new general overrun condition but the GOVRE
flag is not reset.
2. GOVRE is inactive but DRDY is active, does correspond to a new general overrun condition but the GOVRE flag is
not set.
Problem Fix/Workaround
None
41.3.1.6 ADC: GOVRE Bit is not Set when Reading CDR
When reading CDRy (Channel Data Register y) at the same instant as an end of conversion on channel "x" with the
following conditions:
611
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
EOC[x] already active,
DRDY already active,
GOVRE inactive,
previous data stored in LCDR being neither data from channel "y", nor data from channel "x".
GOVRE should be set but is not.
Problem Fix/Workaround
None
41.3.1.7 ADC: GOVRE Bit is not Set when Disabling a Channel
When disabling channel "y" at the same instant as an end of conversion on channel "x", EOC[x] and DRDY being already
active, GOVRE does not rise.
Note: OVRE[x] rises as expected.
Problem Fix/Workaround
None
41.3.1.8 ADC: OVRE Flag Behavior
When the OVRE flag (on channel i) has been set but the related EOC status (of channel i) has been cleared (by a read of
CDRi or LCDR), reading the Status register at the same instant as an end of conversion (causing the set of EOC status
on channel i), does not lead to a reset of the OVRE flag (on channel i) as expected.
Problem Fix/Workaround:
None
41.3.1.9 ADC: EOC Set although Channel Disabled
If a channel is disabled while a conversion is running and if a read of CDR is performed at the same time as an end of
conversion of any channel occurs, the EOC of the channel with the conversion running may rise (whereas it has been
disabled).
Problem Fix/Workaround
Do not take into account the EOC of a disabled channel
41.3.1.10 ADC: Spurious Clear of EOC Flag
If "x" and "y" are two successively converted channels and "z" is yet another enabled channel ("z" being neither "x" nor
"y"), reading CDR on channel "z" at the same instant as an end of conversion on channel "y" automatically clears EOC[x]
instead of EOC[z].
Problem Fix/Workaround
None.
41.3.1.11 ADC: Sleep Mode
If Sleep mode is activated while there is no activity (no conversion is being performed), it will take effect only after a
conversion occurs.
Problem Fix/Workaround
To activate sleep mode as soon as possible, it is recommended to write successively, ADC Mode Register (SLEEP) then
ADC Control Register (START bit field); to start an analog-to-digital conversion, in order put ADC into sleep mode at the
end of this conversion.
612
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
41.3.2 Controller Area Network (CAN)
41.3.2.1 CAN: Low Power Mode and Error Frame
If the Low Power Mode is activated while the CAN is generating an error frame, this error frame may be shortened.
Problem Fix/Workaround
None
41.3.2.2 CAN: Low Power Mode and Pending Transmit Messages
No pending transmit messages may be sent once the CAN Controller enters Low-power Mode.
Problem Fix/Workaround
Check that all messages have been sent by reading the related Flags before entering Low-power Mode.
41.3.3 Ethernet MAC (EMAC)
41.3.3.1 EMAC: RMII Mode
RMII mode is not functional.
Problem Fix/Workaround
None
41.3.3.2 EMAC: Possible Event Loss when Reading EMAC_ISR
If an event occurs within the same clock cycle in which the EMAC_ISR is read, the corresponding bit might be cleared
even though it has not been read at 1. This might lead to the loss of this event.
Problem Fix/Workaround
Each time the software reads EMAC_ISR, it has to check the contents of the Transmit Status Register (EMAC_TSR), the
Receive Status Register (EMAC_RSR) and the Network Status Register (EMAC_NSR), as the possible lost event is still
notified in one of these registers.
41.3.3.3 EMAC: Possible Event Loss when Reading the Statistics Register Block
If an event occurs within the same clock cycle during which a statistics register is read, the corresponding counter might
lose this event. This might lead to the loss of the incrementation of one for this counter.
Problem Fix/Workaround
None
41.3.4 Peripheral Input/Output (PIO)
41.3.4.1 PIO: Leakage on PB27 - PB30
When PB27, PB28, PB29 or PB30 (the I/O lines multiplexed with the analog inputs) are set as digital inputs with pull-up
disabled, the leakage can be 25 µA in worst case and 90 nA in typical case per I/O when the I/O is set externally at low
level.
Problem Fix/Workaround
Set the I/O to VDDIO by internal or external pull-up.
613
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
41.3.4.2 PIO: Electrical Characteristics on NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, the voltage of the I/O stabilizes
at VPull-up.
This condition causes a leakage through VDDIO. This leakage is 45 µA per pad in worst case at 3.3 V.
Problem Fix/Workaround
It is recommended to use an external pull-up if needed.
41.3.4.3 PIO: Drive Low NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, driving the I/O with an output
impedance higher than 500 ohms may not drive the I/O to a logical zero.
Problem Fix/Workaround
Output impedance must be lower than 500 ohms.
41.3.5 Pulse Width Modulation Controller (PWM)
41.3.5.1 PWM: Update when PWM_CCNTx = 0 or 1
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is directly
modified when writing the Channel Update Register.
Problem Fix/Workaround
Check the Channel Counter Register before writing the update register.
41.3.5.2 PWM: Update when PWM_CPRDx = 0
When Channel Period Register equals 0, the period update is not operational.
Problem Fix/Workaround
Do not write 0 in the period register.
41.3.5.3 PWM: Counter Start Value
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
Problem Fix/Workaround
None.
41.3.5.4 PWM: Behavior of CHIDx Status Bits in the PWM_SR Register
Erratic behavior of the CHIDx status bit in the PWM_SR Register. When a channel is disabled by writing in the PWM_DIS
Register just after enabling it (before completion of a Clock Period of the clock selected for the channel), the PWM line is
internally disabled but the CHIDx status bit in the PWM_SR stays at 1.
Problem Fix/Workaround
Vpull-up
VPull-up Min VPull-up Max
VDDIO - 0.65 V VDDIO - 0.45 V
I Leakage
Parameter Typ Max
I Leakage at 3,3V 2.5 µA 45 µA
614
SAM7X Series [DATASHEET]
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Do not disable a channel before completion of one period of the selected clock.
41.3.6 Real Time Timer (RTT)
41.3.6.1 RTT: Possible Event Loss when Reading RTT_SR
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the
corresponding bit might be cleared. This can lead to the loss of this event.
Problem Fix/Workaround:
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
41.3.7 Serial Peripheral Interface (SPI)
41.3.7.1 SPI: Bad tx_ready Behavior when CSAAT = 1 and SCBR = 1
If the SPI2 is programmed with CSAAT = 1, SCBR(baudrate) = 1 and two transfers are performed consecutively on the
same slave with an IDLE state between them, the tx_ready signal does not rise after the second data has been
transferred in the shifter. This can imply for example, that the second data is sent twice.
Problem Fix/Workaround
Do not use the combination CSAAT = 1 and SCBR = 1.
41.3.7.2 SPI: LASTXFER (Last Transfer) Behavior
In FIXED Mode, with CSAAT bit set, and in “PDC mode” the Chip Select can rise depending on the data written in the
SPI_TDR when the TX_EMPTY flag is set. If for example, the PDC writes a “1” in the bit 24 (LASTXFER bit) of the
SPI_TDR, the chip select will rise as soon as the TXEMPTY flag is set.
Problem Fix/Workaround
Use the CS in PIO mode when PDC mode is required and CS has to be maintained between transfers.
41.3.7.3 SPI: SPCK Behavior in Master Mode
SPCK pin can toggle out before the first transfer in Master Mode.
Problem Fix/Workaround
In Master Mode, MSTR bit must be set (in SPI_MR register) before configuring SPI_CSRx registers.
41.3.7.4 SPI: Chip Select and Fixed Mode
In fixed Mode, if a transfer is performed through a PDC on a Chip select different from the Chip select 0, the output
spi_size sampled by the PDC will depend on the field, BITS (Bits per Transfer) of SPI_CSR0 register, whatever the
selected Chip select is. For example, if SPI_CSR0 is configured for a 10-bit transfer whereas SPI_CSR1 is configured for
an 8-bit transfer, when a transfer is performed in Fixed mode through the PDC, on Chip select 1, the transfer will be
considered as a HalfWord transfer.
Problem Fix/Workaround
If a PDC transfer has to be performed in 8 bits, on a Chip select y (y as different from 0), the BITS field of the SPI_CSR0
must be configured in 8 bits, in the same way as the BITS field of the CSRy Register.
41.3.7.5 SPI: Baudrate Set to 1
When Baudrate is set at 1 (i.e. when serial clock frequency equals the system clock frequency) and when the BITS field
of the SPI_CSR register (number of bits to be transmitted) equals an ODD value (in this case 9,11,13 or 15), an
additional pulse will be generated on output SPCK.
Everything is OK if the BITS field equals 8,10,12,14 or 16 and Baudrate = 1.
Problem Fix/Workaround
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None.
41.3.7.6 SPI: Bad Serial Clock Generation on 2nd Chip Select
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
Master Mode
CPOL = 1 and NCPHA = 0
Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when serial clock frequency
equals the system clock frequency) and the other transfers set with SCBR are not equal to 1
Transmitting with the slowest chip select and then with the fastest one, then an additional pulse is generated on
output SPCK during the second transfer.
Problem Fix/Workaround
Do not use a multiple Chip Select configuration where at least one SCRx register is configured with SCBR = 1 and the
others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear.
41.3.8 Synchronous Serial Controller (SSC)
41.3.8.1 SSC: Periodic Transmission Limitations in Master Mode
If the Least Significant Bit is sent first (MSBF = 0), the first TAG during the frame synchro is not sent.
Problem Fix/Workaround
None.
41.3.8.2 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as output and TF is programmed as input, it is impossible to emit data when the start of edge (rising
or falling) of synchro has a Start Delay equal to zero.
Problem Fix/Workaround
None.
41.3.8.3 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as an input and TF is programmed as an output and requested to be set to low/high during data
emission, the Frame Synchro signal is generated one bit clock period after the data start and one data bit is lost. This
problem does not exist when generating a periodic synchro.
Problem Fix/Workaround
The data need to be delayed for one bit clock period with an external assembly. In the following schematic, TD, TK and
NRST are AT91SAM7X signals, TXD is the delayed data to connect to the device.
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41.3.9 Two-wire Interface (TWI)
41.3.9.1 TWI: Clock Divider
The value of CLDIV x 2CKDIV must be less than or equal to 8191, the value of CHDIV x 2CKDIV must be less than or equal
to 8191⋅
Problem Fix/Workaround
None.
41.3.9.2 TWI: Disabling Does not Operate Correctly
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with the bit MSDIS at 1.
Furthermore, the status bits TXCOMP and TXRDY in the Status Register (TWI_SR) are not reset.
Problem Fix/Workaround
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts must be disabled before
disabling the TWI.
41.3.9.3 TWI: NACK Status Bit Lost
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection and the TXCOMP bit rising
in the TWI_SR, the NACK bit is not set.
Problem Fix/Workaround
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as long as transmission is n ot
completed.
TXCOMP and NACK fields are set simultaneously and the NACK field is reset after the read of the TWI_SR.
41.3.9.4 TWI: Possible Receive Holding Register Corruption
When loading the TWI_RHR, the transfer direction is ignored. The last data byte received in the TWI_RHR is corrupted
at the end of the first subsequent transmit data byte. Neither RXRDY nor OVERRUN status bits are set if this occurs.
Problem Fix/Workaround
The user must be sure that received data is read before transmitting any new data.
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41.3.9.5 TWI: Software Reset
when a software reset is performed during a frame and when TWCK is low, it is impossible to initiate a new transfer in
READ or WRITE mode.
Problem Fix/Workaround
None.
41.3.10 Universal Synchronous Asynchronous Receiver Transmitter (USART)
41.3.10.1 USART: CTS in Hardware Handshaking
When Hardware Handshaking is used and if CTS goes low near the end of the start bit, a character can be lost.
CTS must not go high during a time slot occurring between 2 Master Clock periods before and 16 Master Clock periods
after the rising edge of the start bit.
Problem Fix/Workaround
None.
41.3.10.2 USART: Hardware Handshaking – Two Characters Sent
If CTS switches from 0 to 1 during the TX of a character and if the holding register (US_THR) is not empty, the content of
US_THR will also be transmitted.
Problem Fix/Workaround
Don't use the PDC in transmit mode and do not fill US_THR before TXEMPTY is set at 1.
41.3.10.3 USART: RXBRK Flag Error in Asynchronous Mode
In receiver mode, when there are two consecutive characters (without time guard in between), RXBRK is not taken into
account. As a result, the RXBRK flag is not enabled correctly and the frame error flag is set
Problem Fix/Workaround
Constraints on the transmitter device connected to the SAM7X USART receiver side:
The transmitter may use the timeguard feature or send two STOP conditions. Only one STOP condition is taken into
account by the receiver state machine. After this STOP condition, as there is no valid data, the receiver state machine
will go in idle mode and enable the RXBRK flag.
41.3.10.4 USART: DCD is Active High instead of Low.
The DCD signal is active at High level in the USART Modem Mode .
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
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41.4 AT91SAM7X512 Errata - Rev. A Part s
Refer to Section 41.1 “Marking” on page 607.
Note: AT91SAM7X512 Revision A chip ID is 0x275C 0A40.
41.4.1 Analog-to-Digital Converter (ADC)
41.4.1.1 ADC: DRDY Bit Cleared
The DRDY Flag should be clear only after a read of ADC_LCDR (Last Converted Data Register). A read of any
ADC_CDRx register (Channel Data Register) automatically clears the DRDY flag.
Problem Fix/Workaround:
None
41.4.1.2 ADC: DRDY not Cleared on Disable
When reading LCDR at the same instant as an end of conversion, with DRDY already active, DRDY is kept active
regardless of the enable status of the current channel. This sets DRDY, whereas new data is not stored.
Problem Fix/Workaround
None
41.4.1.3 ADC: DRDY Possibly Skipped due to CDR Read
Reading CDR for channel "y" at the same instant as an end of conversion on channel "x" with EOC[x] already active,
leads to skipping to set the DRDY flag if channel "x" is enabled.
Problem Fix/Workaround
Use of DRDY functionality with access to CDR registers should be avoided.
41.4.1.4 ADC: Possible Skip on DRDY when Disabling a Channel
DRDY does not rise when disabling channel "y" at the same time as an end of "x" channel conversion, although data is
stored into CDRx and LCDR.
Problem Fix/Workaround
None.
41.4.1.5 ADC: GOVRE Bit is not Updated
Read of the Status Register at the same instant as an end of conversion leads to skipping the update of the GOVRE
(general overrun) flag. GOVRE is neither reset nor set.
For example, if reading the status while an end of conversion is occurring and:
1. GOVRE is active but DRDY is inactive, does not correspond to a new general overrun condition but the GOVRE
flag is not reset.
2. GOVRE is inactive but DRDY is active, does correspond to a new general overrun condition but the GOVRE flag is
not set.
Problem Fix/Workaround
None
41.4.1.6 ADC: GOVRE Bit is not Set when Reading CDR
When reading CDRy (Channel Data Register y) at the same instant as an end of conversion on channel "x" with the
following conditions:
EOC[x] already active,
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DRDY already active,
GOVRE inactive,
previous data stored in LCDR being neither data from channel "y", nor data from channel "x".
GOVRE should be set but is not.
Problem Fix/Workaround
None
41.4.1.7 ADC: GOVRE Bit is not Set when Disabling a Channel
When disabling channel "y" at the same instant as an end of conversion on channel "x", EOC[x] and DRDY being already
active, GOVRE does not rise.
Note: OVRE[x] rises as expected.
Problem Fix/Workaround
None
41.4.1.8 ADC: OVRE Flag Behavior
When the OVRE flag (on channel i) has been set but the related EOC status (of channel i) has been cleared (by a read of
CDRi or LCDR), reading the Status register at the same instant as an end of conversion (causing the set of EOC status
on channel i), does not lead to a reset of the OVRE flag (on channel i) as expected.
Problem Fix/Workaround:
None
41.4.1.9 ADC: EOC Set although Channel Disabled
If a channel is disabled while a conversion is running and if a read of CDR is performed at the same time as an end of
conversion of any channel occurs, the EOC of the channel with the conversion running may rise (whereas it has been
disabled).
Problem Fix/Workaround
Do not take into account the EOC of a disabled channel
41.4.1.10 ADC: Spurious Clear of EOC Flag
If "x" and "y" are two successively converted channels and "z" is yet another enabled channel ("z" being neither "x" nor
"y"), reading CDR on channel "z" at the same instant as an end of conversion on channel "y" automatically clears EOC[x]
instead of EOC[z].
Problem Fix/Workaround
None.
41.4.1.11 ADC: Sleep Mode
If Sleep mode is activated while there is no activity (no conversion is being performed), it will take effect only after a
conversion occurs.
Problem Fix/Workaround
To activate sleep mode as soon as possible, it is recommended to write successively, ADC Mode Register (SLEEP) then
ADC Control Register (START bit field); to start an analog-to-digital conversion, in order put ADC into sleep mode at the
end of this conversion.
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41.4.2 Controller Area Network (CAN)
41.4.2.1 CAN: Low Power Mode and Error Frame
If the Low Power Mode is activated while the CAN is generating an error frame, this error frame may be shortened.
Problem Fix/Workaround
None
41.4.2.2 CAN: Low Power Mode and Pending Transmit Messages
No pending transmit messages may be sent once the CAN Controller enters Low-power Mode.
Problem Fix/Workaround
Check that all messages have been sent by reading the related Flags before entering Low-power Mode.
41.4.3 Embedded Flash Controller (EFC)
41.4.3.1 EFC: Embedded Flash Access Time
The embedded Flash maximum access time is 25 MHz (instead of 30 MHz at zero Wait State (FWS = 0). The maximum
operating frequency with one Wait State (FWS = 1) is still 55 MHz.
Problem Fix/Workaround
Set one wait state (FWS = 1) if the frequency is above 25 MHz.
41.4.4 Ethernet MAC (EMAC)
41.4.4.1 EMAC: Possible Event Loss when Reading EMAC_ISR
If an event occurs within the same clock cycle in which the EMAC_ISR is read, the corresponding bit might be cleared
even though it has not been read at 1. This might lead to the loss of this event.
Problem Fix/Workaround
Each time the software reads EMAC_ISR, it has to check the contents of the Transmit Status Register (EMAC_TSR), the
Receive Status Register (EMAC_RSR) and the Network Status Register (EMAC_NSR), as the possible lost event is still
notified in one of these registers.
41.4.4.2 EMAC: Possible Event Loss when Reading the Statistics Register Block
If an event occurs within the same clock cycle during which a statistics register is read, the corresponding counter might
lose this event. This might lead to the loss of the incrementation of one for this counter.
Problem Fix/Workaround
None
41.4.5 Peripheral Input/Output (PIO)
41.4.5.1 PIO: Leakage on PB27 - PB30
When PB27, PB28, PB29 or PB30 (the I/O lines multiplexed with the analog inputs) are set as digital inputs with pull-up
disabled, the leakage can be 25 µA in worst case and 90 nA in typical case per I/O when the I/O is set externally at low
level.
Problem Fix/Workaround
Set the I/O to VDDIO by internal or external pull-up.
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41.4.5.2 PIO: Electrical Characteristics on NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, the voltage of the I/O stabilizes
at VPull-up.
This condition causes a leakage through VDDIO. This leakage is 45 µA per pad in worst case at 3.3 V.
Problem Fix/Workaround
It is recommended to use an external pull-up if needed.
41.4.5.3 PIO: Drive Low NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, driving the I/O with an output
impedance higher than 500 ohms may not drive the I/O to a logical zero.
Problem Fix/Workaround
Output impedance must be lower than 500 ohms.
41.4.6 Pulse Width Modulation Controller (PWM)
41.4.6.1 PWM: Update when PWM_CCNTx = 0 or 1
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is directly
modified when writing the Channel Update Register.
Problem Fix/Workaround
Check the Channel Counter Register before writing the update register.
41.4.6.2 PWM: Update when PWM_CPRDx = 0
When Channel Period Register equals 0, the period update is not operational.
Problem Fix/Workaround
Do not write 0 in the period register.
41.4.6.3 PWM: Counter Start Value
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
Problem Fix/Workaround
None.
41.4.6.4 PWM: Behavior of CHIDx Status Bits in the PWM_SR Register
Erratic behavior of the CHIDx status bit in the PWM_SR Register. When a channel is disabled by writing in the PWM_DIS
Register just after enabling it (before completion of a Clock Period of the clock selected for the channel), the PWM line is
internally disabled but the CHIDx status bit in the PWM_SR stays at 1.
Problem Fix/Workaround
Vpull-up
VPull-up Min VPull-up Max
VDDIO - 0.65 V VDDIO - 0.45 V
I Leakage
Parameter Typ Max
I Leakage at 3,3V 2.5 µA 45 µA
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Do not disable a channel before completion of one period of the selected clock.
41.4.7 Real Time Timer (RTT)
41.4.7.1 RTT: Possible Event Loss when Reading RTT_SR
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the
corresponding bit might be cleared. This can lead to the loss of this event.
Problem Fix/Workaround:
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
41.4.8 Serial Peripheral Interface (SPI)
41.4.8.1 SPI: Bad tx_ready Behavior when CSAAT = 1 and SCBR = 1
If the SPI2 is programmed with CSAAT = 1, SCBR(baudrate) = 1 and two transfers are performed consecutively on the
same slave with an IDLE state between them, the tx_ready signal does not rise after the second data has been
transferred in the shifter. This can imply for example, that the second data is sent twice.
Problem Fix/Workaround
Do not use the combination CSAAT = 1 and SCBR = 1.
41.4.8.2 SPI: LASTXFER (Last Transfer) Behavior
In FIXED Mode, with CSAAT bit set, and in “PDC mode” the Chip Select can rise depending on the data written in the
SPI_TDR when the TX_EMPTY flag is set. If for example, the PDC writes a “1” in the bit 24 (LASTXFER bit) of the
SPI_TDR, the chip select will rise as soon as the TXEMPTY flag is set.
Problem Fix/Workaround
Use the CS in PIO mode when PDC mode is required and CS has to be maintained between transfers.
41.4.8.3 SPI: SPCK Behavior in Master Mode
SPCK pin can toggle out before the first transfer in Master Mode.
Problem Fix/Workaround
In Master Mode, MSTR bit must be set (in SPI_MR register) before configuring SPI_CSRx registers.
41.4.8.4 SPI: Chip Select and Fixed Mode
In fixed Mode, if a transfer is performed through a PDC on a Chip select different from the Chip select 0, the output
spi_size sampled by the PDC will depend on the field, BITS (Bits per Transfer) of SPI_CSR0 register, whatever the
selected Chip select is. For example, if SPI_CSR0 is configured for a 10-bit transfer whereas SPI_CSR1 is configured for
an 8-bit transfer, when a transfer is performed in Fixed mode through the PDC, on Chip select 1, the transfer will be
considered as a HalfWord transfer.
Problem Fix/Workaround
If a PDC transfer has to be performed in 8 bits, on a Chip select y (y as different from 0), the BITS field of the SPI_CSR0
must be configured in 8 bits, in the same way as the BITS field of the CSRy Register.
41.4.8.5 SPI: Baudrate Set to 1
When Baudrate is set at 1 (i.e. when serial clock frequency equals the system clock frequency) and when the BITS field
of the SPI_CSR register (number of bits to be transmitted) equals an ODD value (in this case 9,11,13 or 15), an
additional pulse will be generated on output SPCK.
Everything is OK if the BITS field equals 8,10,12,14 or 16 and Baudrate = 1.
Problem Fix/Workaround
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None.
41.4.8.6 SPI: Bad Serial Clock Generation on 2nd Chip Select
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
Master mode
CPOL = 1 and NCPHA = 0
Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when serial clock frequency
equals the system clock frequency) and the other transfers set with SCBR are not equal to 1
Transmitting with the slowest chip select and then with the fastest one, then an additional pulse is generated on
output SPCK during the second transfer.
Problem Fix/Workaround
Do not use a multiple Chip Select configuration where at least one SCRx register is configured with SCBR = 1 and the
others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear
41.4.8.7 SPI: Software Reset must be Written Twice
If a software reset (SWRST in the SPI Control Register) is performed, the SPI may not work properly (the clock is
enabled before the chip select.)
Problem Fix/Workaround
The SPI Control Register field, SWRST (Software Reset) needs to be written twice to be correctly set.
41.4.9 Synchronous Serial Controller (SSC)
41.4.9.1 SSC: Periodic Transmission Limitations in Master Mode
If the Least Significant Bit is sent first (MSBF = 0), the first TAG during the frame synchro is not sent.
Problem Fix/Workaround
None.
41.4.9.2 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as output and TF is programmed as input, it is impossible to emit data when the start of edge (rising
or falling) of synchro has a Start Delay equal to zero.
Problem Fix/Workaround
None.
41.4.9.3 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as an input and TF is programmed as an output and requested to be set to low/high during data
emission, the Frame Synchro signal is generated one bit clock period after the data start and one data bit is lost. This
problem does not exist when generating a periodic synchro.
Problem Fix/Workaround
The data need to be delayed for one bit clock period with an external assembly. In the following schematic, TD, TK and
NRST are AT91SAM7X signals, TXD is the delayed data to connect to the device.
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41.4.10 Two-wire Interface (TWI)
41.4.10.1 TWI: Clock Divider
The value of CLDIV x 2CKDIV must be less than or equal to 8191, the value of CHDIV x 2CKDIV must be less than or equal
to 8191⋅
Problem Fix/Workaround
None.
41.4.10.2 TWI: Disabling Does not Operate Correctly
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with the bit MSDIS at 1.
Furthermore, the status bits TXCOMP and TXRDY in the Status Register (TWI_SR) are not reset.
Problem Fix/Workaround
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts must be disabled before
disabling the TWI.
41.4.10.3 TWI: NACK Status Bit Lost
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection and the TXCOMP bit rising
in the TWI_SR, the NACK bit is not set.
Problem Fix/Workaround
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as long as transmission is n ot
completed.
TXCOMP and NACK fields are set simultaneously and the NACK field is reset after the read of the TWI_SR.
41.4.10.4 TWI: Possible Receive Holding Register Corruption
When loading the TWI_RHR, the transfer direction is ignored. The last data byte received in the TWI_RHR is corrupted
at the end of the first subsequent transmit data byte. Neither RXRDY nor OVERRUN status bits are set if this occurs.
Problem Fix/Workaround
The user must be sure that received data is read before transmitting any new data.
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41.4.10.5 TWI: Software Reset
when a software reset is performed during a frame and when TWCK is low, it is impossible to initiate a new transfer in
READ or WRITE mode.
Problem Fix/Workaround
None.
41.4.11 Universal Synchronous Asynchronous Receiver Transmitter (USART)
41.4.11.1 USART: CTS in Hardware Handshaking
When Hardware Handshaking is used and if CTS goes low near the end of the start bit, a character can be lost.
CTS must not go high during a time slot occurring between 2 Master Clock periods before and 16 Master Clock periods
after the rising edge of the start bit.
Problem Fix/Workaround
None.
41.4.11.2 USART: Hardware Handshaking – Two Characters Sent
If CTS switches from 0 to 1 during the TX of a character and if the holding register (US_THR) is not empty, the content of
US_THR will also be transmitted.
Problem Fix/Workaround
Don't use the PDC in transmit mode and do not fill US_THR before TXEMPTY is set at 1.
41.4.11.3 USART: RXBRK Flag Error in Asynchronous Mode
In receiver mode, when there are two consecutive characters (without time guard in between), RXBRK is not taken into
account. As a result, the RXBRK flag is not enabled correctly and the frame error flag is set
Problem Fix/Workaround
Constraints on the transmitter device connected to the SAM7X USART receiver side:
The transmitter may use the timeguard feature or send two STOP conditions. Only one STOP condition is taken into
account by the receiver state machine. After this STOP condition, as there is no valid data, the receiver state machine
will go in idle mode and enable the RXBRK flag.
41.4.11.4 USART: DCD is Active High instead of Low.
The DCD signal is active at High level in the USART Modem Mode .
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
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41.5 AT91SAM7X256/128 Errata - Rev. B Part s
Refer to Section 41.1 “Marking” on page 607.
Note: AT91SAM7X256 Revision B chip ID is 0x275B 0940.
AT91SAM7X128 Revision B chip ID is 0x275A 0740.
41.5.1 Analog-to-Digital Converter (ADC)
41.5.1.1 ADC: DRDY Bit Cleared
The DRDY Flag should be clear only after a read of ADC_LCDR (Last Converted Data Register). A read of any
ADC_CDRx register (Channel Data Register) automatically clears the DRDY flag.
Problem Fix/Workaround:
None
41.5.1.2 ADC: DRDY not Cleared on Disable
When reading LCDR at the same instant as an end of conversion, with DRDY already active, DRDY is kept active
regardless of the enable status of the current channel. This sets DRDY, whereas new data is not stored.
Problem Fix/Workaround
None
41.5.1.3 ADC: DRDY Possibly Skipped due to CDR Read
Reading CDR for channel "y" at the same instant as an end of conversion on channel "x" with EOC[x] already active,
leads to skipping to set the DRDY flag if channel "x" is enabled.
Problem Fix/Workaround
Use of DRDY functionality with access to CDR registers should be avoided.
41.5.1.4 ADC: Possible Skip on DRDY when Disabling a Channel
DRDY does not rise when disabling channel "y" at the same time as an end of "x" channel conversion, although data is
stored into CDRx and LCDR.
Problem Fix/Workaround
None.
41.5.1.5 ADC: GOVRE Bit is not Updated
Read of the Status Register at the same instant as an end of conversion leads to skipping the update of the GOVRE
(general overrun) flag. GOVRE is neither reset nor set.
For example, if reading the status while an end of conversion is occurring and:
1. GOVRE is active but DRDY is inactive, does not correspond to a new general overrun condition but the GOVRE
flag is not reset.
2. GOVRE is inactive but DRDY is active, does correspond to a new general overrun condition but the GOVRE flag is
not set.
Problem Fix/Workaround
None
41.5.1.6 ADC: GOVRE Bit is not Set when Reading CDR
When reading CDRy (Channel Data Register y) at the same instant as an end of conversion on channel "x" with the
following conditions:
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EOC[x] already active,
DRDY already active,
GOVRE inactive,
previous data stored in LCDR being neither data from channel "y", nor data from channel "x".
GOVRE should be set but is not.
Problem Fix/Workaround
None
41.5.1.7 ADC: GOVRE Bit is not Set when Disabling a Channel
When disabling channel "y" at the same instant as an end of conversion on channel "x", EOC[x] and DRDY being already
active, GOVRE does not rise.
Note: OVRE[x] rises as expected.
Problem Fix/Workaround
None
41.5.1.8 ADC: OVRE Flag Behavior
When the OVRE flag (on channel i) has been set but the related EOC status (of channel i) has been cleared (by a read of
CDRi or LCDR), reading the Status register at the same instant as an end of conversion (causing the set of EOC status
on channel i), does not lead to a reset of the OVRE flag (on channel i) as expected.
Problem Fix/Workaround:
None
41.5.1.9 ADC: EOC Set although Channel Disabled
If a channel is disabled while a conversion is running and if a read of CDR is performed at the same time as an end of
conversion of any channel occurs, the EOC of the channel with the conversion running may rise (whereas it has been
disabled).
Problem Fix/Workaround
Do not take into account the EOC of a disabled channel
41.5.1.10 ADC: Spurious Clear of EOC Flag
If "x" and "y" are two successively converted channels and "z" is yet another enabled channel ("z" being neither "x" nor
"y"), reading CDR on channel "z" at the same instant as an end of conversion on channel "y" automatically clears EOC[x]
instead of EOC[z].
Problem Fix/Workaround
None.
41.5.1.11 ADC: Sleep Mode
If Sleep mode is activated while there is no activity (no conversion is being performed), it will take effect only after a
conversion occurs.
Problem Fix/Workaround
To activate sleep mode as soon as possible, it is recommended to write successively, ADC Mode Register (SLEEP) then
ADC Control Register (START bit field); to start an analog-to-digital conversion, in order put ADC into sleep mode at the
end of this conversion.
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41.5.2 Controller Area Network (CAN)
41.5.2.1 CAN: Low Power Mode and Error Frame
If the Low Power Mode is activated while the CAN is generating an error frame, this error frame may be shortened.
Problem Fix/Workaround
None
41.5.2.2 CAN: Low Power Mode and Pending Transmit Messages
No pending transmit messages may be sent once the CAN Controller enters Low-power Mode.
Problem Fix/Workaround
Check that all messages have been sent by reading the related Flags before entering Low-power Mode.
41.5.3 Ethernet MAC (EMAC)
41.5.3.1 EMAC: RMII Mode
RMII mode is not functional.
Problem Fix/Workaround
None
41.5.3.2 EMAC: Possible Event Loss when Reading EMAC_ISR
If an event occurs within the same clock cycle in which the EMAC_ISR is read, the corresponding bit might be cleared
even though it has not been read at 1. This might lead to the loss of this event.
Problem Fix/Workaround
Each time the software reads EMAC_ISR, it has to check the contents of the Transmit Status Register (EMAC_TSR), the
Receive Status Register (EMAC_RSR) and the Network Status Register (EMAC_NSR), as the possible lost event is still
notified in one of these registers.
41.5.3.3 EMAC: Possible Event Loss when Reading the Statistics Register Block
If an event occurs within the same clock cycle during which a statistics register is read, the corresponding counter might
lose this event. This might lead to the loss of the incrementation of one for this counter.
Problem Fix/Workaround
None
41.5.4 Peripheral Input/Output (PIO)
41.5.4.1 PIO: Electrical Characteristics on NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, the voltage of the I/O stabilizes
at VPull-up.
Vpull-up
VPull-up Min VPull-up Max
VDDIO - 0.65 V VDDIO - 0.45 V
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This condition causes a leakage through VDDIO. This leakage is 45 µA per pad in worst case at 3.3 V.
Problem Fix/Workaround
It is recommended to use an external pull-up if needed.
41.5.4.2 PIO: Drive Low NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, driving the I/O with an output
impedance higher than 500 ohms may not drive the I/O to a logical zero.
Problem Fix/Workaround
Output impedance must be lower than 500 ohms.
41.5.5 Pulse Width Modulation Controller (PWM)
41.5.5.1 PWM: Update when PWM_CCNTx = 0 or 1
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is directly
modified when writing the Channel Update Register.
Problem Fix/Workaround
Check the Channel Counter Register before writing the update register.
41.5.5.2 PWM: Update when PWM_CPRDx = 0
When Channel Period Register equals 0, the period update is not operational.
Problem Fix/Workaround
Do not write 0 in the period register.
41.5.5.3 PWM: Counter Start Value
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
Problem Fix/Workaround
None.
41.5.5.4 PWM: Behavior of CHIDx Status Bits in the PWM_SR Register
Erratic behavior of the CHIDx status bit in the PWM_SR Register. When a channel is disabled by writing in the PWM_DIS
Register just after enabling it (before completion of a Clock Period of the clock selected for the channel), the PWM line is
internally disabled but the CHIDx status bit in the PWM_SR stays at 1.
Problem Fix/Workaround
Do not disable a channel before completion of one period of the selected clock.
41.5.6 Real Time Timer (RTT)
41.5.6.1 RTT: Possible Event Loss when Reading RTT_SR
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the
corresponding bit might be cleared. This can lead to the loss of this event.
I Leakage
Parameter Typ Max
I Leakage at 3,3V 2.5 µA 45 µA
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Problem Fix/Workaround:
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
41.5.7 Serial Peripheral Interface (SPI)
41.5.7.1 SPI: Bad tx_ready Behavior when CSAAT = 1 and SCBR = 1
If the SPI2 is programmed with CSAAT = 1, SCBR(baudrate) = 1 and two transfers are performed consecutively on the
same slave with an IDLE state between them, the tx_ready signal does not rise after the second data has been
transferred in the shifter. This can imply for example, that the second data is sent twice.
Problem Fix/Workaround
Do not use the combination CSAAT = 1 and SCBR = 1.
41.5.7.2 SPI: LASTXFER (Last Transfer) Behavior
In FIXED Mode, with CSAAT bit set, and in “PDC mode” the Chip Select can rise depending on the data written in the
SPI_TDR when the TX_EMPTY flag is set. If for example, the PDC writes a “1” in the bit 24 (LASTXFER bit) of the
SPI_TDR, the chip select will rise as soon as the TXEMPTY flag is set.
Problem Fix/Workaround
Use the CS in PIO mode when PDC mode is required and CS has to be maintained between transfers.
41.5.7.3 SPI: SPCK Behavior in Master Mode
SPCK pin can toggle out before the first transfer in Master Mode.
Problem Fix/Workaround
In Master Mode, MSTR bit must be set (in SPI_MR register) before configuring SPI_CSRx registers.
41.5.7.4 SPI: Chip Select and Fixed Mode
In fixed Mode, if a transfer is performed through a PDC on a Chip select different from the Chip select 0, the output
spi_size sampled by the PDC will depend on the field, BITS (Bits per Transfer) of SPI_CSR0 register, whatever the
selected Chip select is. For example, if SPI_CSR0 is configured for a 10-bit transfer whereas SPI_CSR1 is configured for
an 8-bit transfer, when a transfer is performed in Fixed mode through the PDC, on Chip select 1, the transfer will be
considered as a HalfWord transfer.
Problem Fix/Workaround
If a PDC transfer has to be performed in 8 bits, on a Chip select y (y as different from 0), the BITS field of the SPI_CSR0
must be configured in 8 bits, in the same way as the BITS field of the CSRy Register.
41.5.7.5 SPI: Baudrate Set to 1
When Baudrate is set at 1 (i.e. when serial clock frequency equals the system clock frequency) and when the BITS field
of the SPI_CSR register (number of bits to be transmitted) equals an ODD value (in this case 9,11,13 or 15), an
additional pulse will be generated on output SPCK.
Everything is OK if the BITS field equals 8,10,12,14 or 16 and Baudrate = 1.
Problem Fix/Workaround
None.
41.5.7.6 SPI: Bad Serial Clock Generation on 2nd Chip Select
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
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Master Mode
CPOL = 1 and NCPHA = 0
Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when serial clock frequency
equals the system clock frequency) and the other transfers set with SCBR are not equal to 1
Transmitting with the slowest chip select and then with the fastest one, then an additional pulse is generated on
output SPCK during the second transfer.
Problem Fix/Workaround
Do not use a multiple Chip Select configuration where at least one SCRx register is configured with SCBR = 1 and the
others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear.
41.5.7.7 SPI: Software Reset must be Written Twice
If a software reset (SWRST in the SPI Control Register) is performed, the SPI may not work properly (the clock is
enabled before the chip select.)
Problem Fix/Workaround
The SPI Control Register field, SWRST (Software Reset) needs to be written twice to be correctly set.
41.5.8 Synchronous Serial Controller (SSC)
41.5.8.1 SSC: Periodic Transmission Limitations in Master Mode
If the Least Significant Bit is sent first (MSBF = 0), the first TAG during the frame synchro is not sent.
Problem Fix/Workaround
None.
41.5.8.2 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as output and TF is programmed as input, it is impossible to emit data when the start of edge (rising
or falling) of synchro has a Start Delay equal to zero.
Problem Fix/Workaround
None.
41.5.8.3 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as an input and TF is programmed as an output and requested to be set to low/high during data
emission, the Frame Synchro signal is generated one bit clock period after the data start and one data bit is lost. This
problem does not exist when generating a periodic synchro.
Problem Fix/Workaround
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The data need to be delayed for one bit clock period with an external assembly. In the following schematic, TD, TK and
NRST are AT91SAM7X signals, TXD is the delayed data to connect to the device.
41.5.9 Two-wire Interface (TWI)
41.5.9.1 TWI: Clock Divider
The value of CLDIV x 2CKDIV must be less than or equal to 8191, the value of CHDIV x 2CKDIV must be less than or equal
to 8191⋅
Problem Fix/Workaround
None.
41.5.9.2 TWI: Disabling Does not Operate Correctly
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with the bit MSDIS at 1.
Furthermore, the status bits TXCOMP and TXRDY in the Status Register (TWI_SR) are not reset.
Problem Fix/Workaround
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts must be disabled before
disabling the TWI.
41.5.9.3 TWI: NACK Status Bit Lost
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection and the TXCOMP bit rising
in the TWI_SR, the NACK bit is not set.
Problem Fix/Workaround
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as long as transmission is n ot
completed.
TXCOMP and NACK fields are set simultaneously and the NACK field is reset after the read of the TWI_SR.
41.5.9.4 TWI: Possible Receive Holding Register Corruption
When loading the TWI_RHR, the transfer direction is ignored. The last data byte received in the TWI_RHR is corrupted
at the end of the first subsequent transmit data byte. Neither RXRDY nor OVERRUN status bits are set if this occurs.
Problem Fix/Workaround
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The user must be sure that received data is read before transmitting any new data.
41.5.9.5 TWI: Software Reset
when a software reset is performed during a frame and when TWCK is low, it is impossible to initiate a new transfer in
READ or WRITE mode.
Problem Fix/Workaround
None.
41.5.10 Universal Synchronous Asynchronous Receiver Transmitter (USART)
41.5.10.1 USART: CTS in Hardware Handshaking
When Hardware Handshaking is used and if CTS goes low near the end of the start bit, a character can be lost.
CTS must not go high during a time slot occurring between 2 Master Clock periods before and 16 Master Clock periods
after the rising edge of the start bit.
Problem Fix/Workaround
None.
41.5.10.2 USART: Hardware Handshaking – Two Characters Sent
If CTS switches from 0 to 1 during the TX of a character and if the holding register (US_THR) is not empty, the content of
US_THR will also be transmitted.
Problem Fix/Workaround
Don't use the PDC in transmit mode and do not fill US_THR before TXEMPTY is set at 1.
41.5.10.3 USART: RXBRK Flag Error in Asynchronous Mode
In receiver mode, when there are two consecutive characters (without time guard in between), RXBRK is not taken into
account. As a result, the RXBRK flag is not enabled correctly and the frame error flag is set
Problem Fix/Workaround
Constraints on the transmitter device connected to the SAM7X USART receiver side:
The transmitter may use the timeguard feature or send two STOP conditions. Only one STOP condition is taken into
account by the receiver state machine. After this STOP condition, as there is no valid data, the receiver state machine
will go in idle mode and enable the RXBRK flag.
41.5.10.4 USART: DCD is Active High instead of Low
The DCD signal is active at High level in the USART Modem Mode.
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
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41.6 AT91SAM7X512 Errata - Rev. B Part s
Refer to Section 41.1 “Marking” on page 607.
Note: AT91SAM7X512 Revision B chip ID is 0x0x275C 0A41.
41.6.1 Analog-to-Digital Converter (ADC)
41.6.1.1 ADC: DRDY Bit Cleared
The DRDY Flag should be clear only after a read of ADC_LCDR (Last Converted Data Register). A read of any
ADC_CDRx register (Channel Data Register) automatically clears the DRDY flag.
Problem Fix/Workaround:
None
41.6.1.2 ADC: DRDY not Cleared on Disable
When reading LCDR at the same instant as an end of conversion, with DRDY already active, DRDY is kept active
regardless of the enable status of the current channel. This sets DRDY, whereas new data is not stored.
Problem Fix/Workaround
None
41.6.1.3 ADC: DRDY Possibly Skipped due to CDR Read
Reading CDR for channel "y" at the same instant as an end of conversion on channel "x" with EOC[x] already active,
leads to skipping to set the DRDY flag if channel "x" is enabled.
Problem Fix/Workaround
Use of DRDY functionality with access to CDR registers should be avoided.
41.6.1.4 ADC: Possible Skip on DRDY when Disabling a Channel
DRDY does not rise when disabling channel "y" at the same time as an end of "x" channel conversion, although data is
stored into CDRx and LCDR.
Problem Fix/Workaround
None.
41.6.1.5 ADC: GOVRE Bit is not Updated
Read of the Status Register at the same instant as an end of conversion leads to skipping the update of the GOVRE
(general overrun) flag. GOVRE is neither reset nor set.
For example, if reading the status while an end of conversion is occurring and:
1. GOVRE is active but DRDY is inactive, does not correspond to a new general overrun condition but the GOVRE
flag is not reset.
2. GOVRE is inactive but DRDY is active, does correspond to a new general overrun condition but the GOVRE flag is
not set.
Problem Fix/Workaround
None
41.6.1.6 ADC: GOVRE Bit is not Set when Reading CDR
When reading CDRy (Channel Data Register y) at the same instant as an end of conversion on channel "x" with the
following conditions:
EOC[x] already active,
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DRDY already active,
GOVRE inactive,
previous data stored in LCDR being neither data from channel "y", nor data from channel "x".
GOVRE should be set but is not.
Problem Fix/Workaround
None
41.6.1.7 ADC: GOVRE Bit is not Set when Disabling a Channel
When disabling channel "y" at the same instant as an end of conversion on channel "x", EOC[x] and DRDY being already
active, GOVRE does not rise.
Note: OVRE[x] rises as expected.
Problem Fix/Workaround
None
41.6.1.8 ADC: OVRE Flag Behavior
When the OVRE flag (on channel i) has been set but the related EOC status (of channel i) has been cleared (by a read of
CDRi or LCDR), reading the Status register at the same instant as an end of conversion (causing the set of EOC status
on channel i), does not lead to a reset of the OVRE flag (on channel i) as expected.
Problem Fix/Workaround:
None
41.6.1.9 ADC: EOC Set although Channel Disabled
If a channel is disabled while a conversion is running and if a read of CDR is performed at the same time as an end of
conversion of any channel occurs, the EOC of the channel with the conversion running may rise (whereas it has been
disabled).
Problem Fix/Workaround
Do not take into account the EOC of a disabled channel
41.6.1.10 ADC: Spurious Clear of EOC Flag
If "x" and "y" are two successively converted channels and "z" is yet another enabled channel ("z" being neither "x" nor
"y"), reading CDR on channel "z" at the same instant as an end of conversion on channel "y" automatically clears EOC[x]
instead of EOC[z].
Problem Fix/Workaround
None.
41.6.1.11 ADC: Sleep Mode
If Sleep mode is activated while there is no activity (no conversion is being performed), it will take effect only after a
conversion occurs.
Problem Fix/Workaround
To activate sleep mode as soon as possible, it is recommended to write successively, ADC Mode Register (SLEEP) then
ADC Control Register (START bit field); to start an analog-to-digital conversion, in order put ADC into sleep mode at the
end of this conversion.
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41.6.2 Controller Area Network (CAN)
41.6.2.1 CAN: Low Power Mode and Error Frame
If the Low Power Mode is activated while the CAN is generating an error frame, this error frame may be shortened.
Problem Fix/Workaround
None
41.6.2.2 CAN: Low Power Mode and Pending Transmit Messages
No pending transmit messages may be sent once the CAN Controller enters Low-power Mode.
Problem Fix/Workaround
Check that all messages have been sent by reading the related Flags before entering Low-power Mode.
41.6.3 Embedded Flash Controller (EFC)
41.6.3.1 EFC: Embedded Flash Access Time
The embedded Flash maximum access time (FWS) is shown in Table 41-2:
Problem Fix/Workaround
Set the number of wait states (FWS) depending on frequency as specified in Table 41-2.
41.6.4 Ethernet MAC (EMAC)
41.6.4.1 EMAC: Possible Event Loss when Reading EMAC_ISR
If an event occurs within the same clock cycle in which the EMAC_ISR is read, the corresponding bit might be cleared
even though it has not been read at 1. This might lead to the loss of this event.
Problem Fix/Workaround
Each time the software reads EMAC_ISR, it has to check the contents of the Transmit Status Register (EMAC_TSR), the
Receive Status Register (EMAC_RSR) and the Network Status Register (EMAC_NSR), as the possible lost event is still
notified in one of these registers.
41.6.4.2 EMAC: Possible Event Loss when Reading the Statistics Register Block
If an event occurs within the same clock cycle during which a statistics register is read, the corresponding counter might
lose this event. This might lead to the loss of the incrementation of one for this counter.
Problem Fix/Workaround
None
Table 41-2. Embedded Flash Access Time
Flash Wait State (FWS) Read Operations Maximum Operating Frequ ency (MHz)
0 1 cycle 16
1 2 cycles 32
2 3 cycels 48
3 4 cycles 55
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41.6.5 Peripheral Input/Output (PIO)
41.6.5.1 PIO: Leakage on PB27 - PB30
When PB27, PB28, PB29 or PB30 (the I/O lines multiplexed with the analog inputs) are set as digital inputs with pull-up
disabled, the leakage can be 25 µA in worst case and 90 nA in typical case per I/O when the I/O is set externally at low
level.
Problem Fix/Workaround
Set the I/O to VDDIO by internal or external pull-up.
41.6.5.2 PIO: Electrical Characteristics on NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, the voltage of the I/O stabilizes
at VPull-up.
This condition causes a leakage through VDDIO. This leakage is 45 µA per pad in worst case at 3.3 V.
Problem Fix/Workaround
It is recommended to use an external pull-up if needed.
41.6.5.3 PIO: Drive Low NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, driving the I/O with an output
impedance higher than 500 ohms may not drive the I/O to a logical zero.
Problem Fix/Workaround
Output impedance must be lower than 500 ohms.
41.6.6 Pulse Width Modulation Controller (PWM)
41.6.6.1 PWM: Update when PWM_CCNTx = 0 or 1
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is directly
modified when writing the Channel Update Register.
Problem Fix/Workaround
Check the Channel Counter Register before writing the update register.
41.6.6.2 PWM: Update when PWM_CPRDx = 0
When Channel Period Register equals 0, the period update is not operational.
Problem Fix/Workaround
Do not write 0 in the period register.
41.6.6.3 PWM: Counter Start Value
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
Vpull-up
VPull-up Min VPull-up Max
VDDIO - 0.65 V VDDIO - 0.45 V
I Leakage
Parameter Typ Max
I Leakage at 3,3V 2.5 µA 45 µA
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Problem Fix/Workaround
None.
41.6.6.4 PWM: Behavior of CHIDx Status Bits in the PWM_SR Register
Erratic behavior of the CHIDx status bit in the PWM_SR Register. When a channel is disabled by writing in the PWM_DIS
Register just after enabling it (before completion of a Clock Period of the clock selected for the channel), the PWM line is
internally disabled but the CHIDx status bit in the PWM_SR stays at 1.
Problem Fix/Workaround
Do not disable a channel before completion of one period of the selected clock.
41.6.7 Real Time Timer (RTT)
41.6.7.1 RTT: Possible Event Loss when Reading RTT_SR
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the
corresponding bit might be cleared. This can lead to the loss of this event.
Problem Fix/Workaround:
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
41.6.8 Serial Peripheral Interface (SPI)
41.6.8.1 SPI: Bad tx_ready Behavior when CSAAT = 1 and SCBR = 1
If the SPI2 is programmed with CSAAT = 1, SCBR(baudrate) = 1 and two transfers are performed consecutively on the
same slave with an IDLE state between them, the tx_ready signal does not rise after the second data has been
transferred in the shifter. This can imply for example, that the second data is sent twice.
Problem Fix/Workaround
Do not use the combination CSAAT = 1 and SCBR = 1.
41.6.8.2 SPI: LASTXFER (Last Transfer) Behavior
In FIXED Mode, with CSAAT bit set, and in “PDC mode” the Chip Select can rise depending on the data written in the
SPI_TDR when the TX_EMPTY flag is set. If for example, the PDC writes a “1” in the bit 24 (LASTXFER bit) of the
SPI_TDR, the chip select will rise as soon as the TXEMPTY flag is set.
Problem Fix/Workaround
Use the CS in PIO mode when PDC mode is required and CS has to be maintained between transfers.
41.6.8.3 SPI: SPCK Behavior in Master Mode
SPCK pin can toggle out before the first transfer in Master Mode.
Problem Fix/Workaround
In Master Mode, MSTR bit must be set (in SPI_MR register) before configuring SPI_CSRx registers.
41.6.8.4 SPI: Chip Select and Fixed Mode
In fixed Mode, if a transfer is performed through a PDC on a Chip select different from the Chip select 0, the output
spi_size sampled by the PDC will depend on the field, BITS (Bits per Transfer) of SPI_CSR0 register, whatever the
selected Chip select is. For example, if SPI_CSR0 is configured for a 10-bit transfer whereas SPI_CSR1 is configured for
an 8-bit transfer, when a transfer is performed in Fixed mode through the PDC, on Chip select 1, the transfer will be
considered as a HalfWord transfer.
Problem Fix/Workaround
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If a PDC transfer has to be performed in 8 bits, on a Chip select y (y as different from 0), the BITS field of the SPI_CSR0
must be configured in 8 bits, in the same way as the BITS field of the CSRy Register.
41.6.8.5 SPI: Baudrate Set to 1
When Baudrate is set at 1 (i.e. when serial clock frequency equals the system clock frequency) and when the BITS field
of the SPI_CSR register (number of bits to be transmitted) equals an ODD value (in this case 9,11,13 or 15), an
additional pulse will be generated on output SPCK.
Everything is OK if the BITS field equals 8,10,12,14 or 16 and Baudrate = 1.
Problem Fix/Workaround
None.
41.6.8.6 SPI: Bad Serial Clock Generation on 2nd Chip Select
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
Master mode
CPOL = 1 and NCPHA = 0
Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when serial clock frequency
equals the system clock frequency) and the other transfers set with SCBR are not equal to 1
Transmitting with the slowest chip select and then with the fastest one, then an additional pulse is generated on
output SPCK during the second transfer.
Problem Fix/Workaround
Do not use a multiple Chip Select configuration where at least one SCRx register is configured with SCBR = 1 and the
others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear
41.6.8.7 SPI: Software Reset must be Written Twice
If a software reset (SWRST in the SPI Control Register) is performed, the SPI may not work properly (the clock is
enabled before the chip select.)
Problem Fix/Workaround
The SPI Control Register field, SWRST (Software Reset) needs to be written twice to be correctly set.
41.6.9 Synchronous Serial Controller (SSC)
41.6.9.1 SSC: Periodic Transmission Limitations in Master Mode
If the Least Significant Bit is sent first (MSBF = 0), the first TAG during the frame synchro is not sent.
Problem Fix/Workaround
None.
41.6.9.2 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as output and TF is programmed as input, it is impossible to emit data when the start of edge (rising
or falling) of synchro has a Start Delay equal to zero.
Problem Fix/Workaround
None.
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41.6.9.3 SSC: Transmitter Limitations in Slave Mode
If TK is programmed as an input and TF is programmed as an output and requested to be set to low/high during data
emission, the Frame Synchro signal is generated one bit clock period after the data start and one data bit is lost. This
problem does not exist when generating a periodic synchro.
Problem Fix/Workaround
The data need to be delayed for one bit clock period with an external assembly. In the following schematic, TD, TK and
NRST are AT91SAM7X signals, TXD is the delayed data to connect to the device.
41.6.10 Two-wire Interface (TWI)
41.6.10.1 TWI: Clock Divider
The value of CLDIV x 2CKDIV must be less than or equal to 8191, the value of CHDIV x 2CKDIV must be less than or equal
to 8191⋅
Problem Fix/Workaround
None.
41.6.10.2 TWI: Disabling Does not Operate Correctly
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with the bit MSDIS at 1.
Furthermore, the status bits TXCOMP and TXRDY in the Status Register (TWI_SR) are not reset.
Problem Fix/Workaround
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts must be disabled before
disabling the TWI.
41.6.10.3 TWI: NACK Status Bit Lost
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection and the TXCOMP bit rising
in the TWI_SR, the NACK bit is not set.
Problem Fix/Workaround
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as long as transmission is n ot
completed.
641
SAM7X Series [DATASHEET]
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TXCOMP and NACK fields are set simultaneously and the NACK field is reset after the read of the TWI_SR.
41.6.10.4 TWI: Possible Receive Holding Register Corruption
When loading the TWI_RHR, the transfer direction is ignored. The last data byte received in the TWI_RHR is corrupted
at the end of the first subsequent transmit data byte. Neither RXRDY nor OVERRUN status bits are set if this occurs.
Problem Fix/Workaround
The user must be sure that received data is read before transmitting any new data.
41.6.10.5 TWI: Software Reset
when a software reset is performed during a frame and when TWCK is low, it is impossible to initiate a new transfer in
READ or WRITE mode.
Problem Fix/Workaround
None.
41.6.11 Universal Synchronous Asynchronous Receiver Transmitter (USART)
41.6.11.1 USART: CTS in Hardware Handshaking
When Hardware Handshaking is used and if CTS goes low near the end of the start bit, a character can be lost.
CTS must not go high during a time slot occurring between 2 Master Clock periods before and 16 Master Clock periods
after the rising edge of the start bit.
Problem Fix/Workaround
None.
41.6.11.2 USART: Hardware Handshaking – Two Characters Sent
If CTS switches from 0 to 1 during the TX of a character and if the holding register (US_THR) is not empty, the content of
US_THR will also be transmitted.
Problem Fix/Workaround
Don't use the PDC in transmit mode and do not fill US_THR before TXEMPTY is set at 1.
41.6.11.3 USART: RXBRK Flag Error in Asynchronous Mode
In receiver mode, when there are two consecutive characters (without time guard in between), RXBRK is not taken into
account. As a result, the RXBRK flag is not enabled correctly and the frame error flag is set
Problem Fix/Workaround
Constraints on the transmitter device connected to the SAM7X USART receiver side:
The transmitter may use the timeguard feature or send two STOP conditions. Only one STOP condition is taken into
account by the receiver state machine. After this STOP condition, as there is no valid data, the receiver state machine
will go in idle mode and enable the RXBRK flag.
41.6.11.4 USART: DCD is Active High instead of Low.
The DCD signal is active at High level in the USART Modem Mode .
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
642
SAM7X Series [DATASHEET]
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41.7 AT91SAM7X256/128 Errata - Rev. C Part s
Refer to Section 41.1 “Marking” on page 607.
Note: AT91SAM7X256 Revision C chip ID is 0x275B 0942.
AT91SAM7X128 Revision C chip ID is 0x275A 0742.
41.7.1 Boundary Scan
41.7.1.1 BSDL: BSDL File for Rev. B Devices Not Compatible with Rev. C Devices
The BSDL file dedicated to Rev. C devices must be used. No other BSDL file is compatible with Rev. C devices.
41.7.2 Embedded Flash Controller (EFC)
41.7.2.1 EFC: Embedded Flash Access Time 2
The embedded Flash maximum access time is 20 MHz (instead of 30 MHz at zero Wait State (FWS = 0).
The maximum operating frequency with one Wait State (FWS = 1) is 48.1 MHz (instead of 55 MHz). Above 48.1 MHz and
up to 55MHz, two Wait States (FWS = 2) are required.
Problem Fix/Workaround
Set the number of Wait States (FWS) according to the frequency requirements described in this errata.
41.7.3 Ethernet MAC (EMAC)
41.7.3.1 EMAC: Possible Event Loss when Reading EMAC_ISR
If an event occurs within the same clock cycle in which the EMAC_ISR is read, the corresponding bit might be cleared
even though it has not been read at 1. This might lead to the loss of this event.
Problem Fix/Workaround
Each time the software reads EMAC_ISR, it has to check the contents of the Transmit Status Register (EMAC_TSR), the
Receive Status Register (EMAC_RSR) and the Network Status Register (EMAC_NSR), as the possible lost event is still
notified in one of these registers.
41.7.3.2 EMAC: Possible Event Loss when Reading the Statistics Register Block
If an event occurs within the same clock cycle during which a statistics register is read, the corresponding counter might
lose this event. This might lead to the loss of the incrementation of one for this counter.
Problem Fix/Workaround
None
41.7.4 Peripheral Input/Output (PIO)
41.7.4.1 PIO: Electrical Characteristics on NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, the voltage of the I/O stabilizes
at VPull-up.
Vpull-up
VPull-up Min VPull-up Max
VDDIO - 0.65 V VDDIO - 0.45 V
643
SAM7X Series [DATASHEET]
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This condition causes a leakage through VDDIO. This leakage is 45 µA per pad in worst case at 3.3 V.
Problem Fix/Workaround
It is recommended to use an external pull-up if needed.
41.7.4.2 PIO: Drive Low NRST, PA0-PA30 and PB0-PB26
When NRST or PA0 - PA30 or PB0 - PB26 are set as digital inputs with pull-up enabled, driving the I/O with an output
impedance higher than 500 ohms may not drive the I/O to a logical zero.
Problem Fix/Workaround
Output impedance must be lower than 500 ohms.
41.7.5 Pulse Width Modulation Controller (PWM)
41.7.5.1 PWM: Update when PWM_CCNTx = 0 or 1
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is directly
modified when writing the Channel Update Register.
Problem Fix/Workaround
Check the Channel Counter Register before writing the update register.
41.7.5.2 PWM: Update when PWM_CPRDx = 0
When Channel Period Register equals 0, the period update is not operational.
Problem Fix/Workaround
Do not write 0 in the period register.
41.7.5.3 PWM: Counter Start Value
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
Problem Fix/Workaround
None.
41.7.6 Real Time Timer (RTT)
41.7.6.1 RTT: Possible Event Loss when Reading RTT_SR
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the
corresponding bit might be cleared. This can lead to the loss of this event.
Problem Fix/Workaround:
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
I Leakage
Parameter Typ Max
I Leakage at 3,3V 2.5 µA 45 µA
644
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
41.7.7 Serial Peripheral Interface (SPI)
41.7.7.1 SPI: Bad Serial Clock Generation on 2nd Chip Select
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
Master Mode
CPOL = 1 and NCPHA = 0
Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when serial clock frequency
equals the system clock frequency) and the other transfers set with SCBR are not equal to 1
Transmitting with the slowest chip select and then with the fastest one, then an additional pulse is generated on
output SPCK during the second transfer.
Problem Fix/Workaround
Do not use a multiple Chip Select configuration where at least one SCRx register is configured with SCBR = 1 and the
others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear.
41.7.8 Universal Synchronous Asynchronous Receiver Transmitter (USART)
41.7.8.1 USART: DCD is Active High instead of Low
The DCD signal is active at High level in the USART Modem Mode.
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
645
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
42. Revision History
The most recent version appears first in the tables that follow.
The acronymn “rfo” indicates change requests made by technical experts during document approval.
Version
6120K Comments
Change
Request
Ref.
Section 29. ”Two-wire Interface (TWI)”
Added bit OVRE to Section 29.6.5 ”TW I Status Register”, Section 29.6.6 ”TWI Interrupt Enable Registe r”,
Section 29.6.7 ”TWI Interrupt Disable Register” and Section 29.6.8 ”TWI Interrupt Mask Register”. 7199
Section 16. ”Watchdog Timer (WDT)”
Section 16.3 ”Functional Description”, added new 5th paragraph with descri ption of watchdog restart
behavior.
Section 16.4.2 ”Watchdog Timer Mode Register” , added note regarding watchdog restart and WDD/WDV
values.
8128
8128
Section 41. ”SAM7X512/256/128 Errata”
Table 41-1, “Errata Summary Table”: added AT91SAM7X512 rev. B column.
Section 41.4 ”AT91SAM7X512 Errata - Rev. A Parts”: added chip ID.
Added new section Section 41.6 ”AT91SAM7X512 Errata - Rev. B Parts”.
Added new errata Section 41.7.1.1 ”BSDL: BSDL File for Rev. B Devices Not Compatible with Rev. C
Devices”
rfo
rfo
9404
9849
Section 40. ”AT91SAM7X Ordering Information”
Added three ordering codes for AT91SAM7X512 MRL B. rfo
Version
6120J Comments
Change
Request
Ref.
Atmel internal document
646
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Version
6120I Comments
Change
Request
Ref.
Ordering Information:
Table 40-1, “Ordering Information”
The following ordering codes added to the table for MRL C.
AT91SAM7X256C-AU
AT91SAM7X256C-CU
AT91SAM7X128C-AU
AT91SAM7X128C-CU
7371
Overview:
Section 9.5 ”Debug Unit”
“Chip ID Registers” , Chip IDs updated with reference to MRL A, B or C. rfo
Product Series Naming Convention:
Except for part ordering and library references, AT91 prefix dr opped from most nomenclature.
AT91SAM7X becomes SAM7X. rfo
Errata:
Table 41-1, “Errata Summary Table”, added.
Section 41.7 ”AT91SAM7X256/128 Errata - Rev. C Parts”, added. 7371
Section 41.3 ”AT91SAM7X256/128 Errata - Rev. A Parts”, added note specific to Rev A chip IDs.
Section 41.4 ”AT91SAM7X512 Errata - Rev. A Parts”, added note specific to Rev A chip ID.
Section 41.5 ”AT91SAM7X256/128 Errata - Rev. B Parts”, added note specific to Rev B chip IDs.
Section 41.4.3.1 ”EFC: Embedd ed Flash Access Time” Problem Fix/Workaround, revised.
rfo
Section 41.3.10.3 ”USART: RXBRK Flag Error in Asynchronous Mode”, Revised.
Section 41.4.11.3 ”USART: RXBRK Flag Error in Asynchronous Mode”, Revised.
Section 41.5.10.3 ”USART: RXBRK Flag Error in Asynchronous Mode”, Revised. 6624
Electrical Characteristic s:
Table 38-2, “DC Characteristics” VOL and VOH rows revised (removed 1.65 t0 1.95V VVDDIO values).
Table 38-9, Table 38-10, Table 38-10, fixed typos in Units column: µW or W => µΩ or Ω.7211
6484
EFC:
Section 19.2.4.4 ”General-purpose NVM Bits”, updated the last paragraph.
Figure 19-6,”Example of Partial Page Programming” Text added befow figure 6233
6825
Debug and Test Features:
“MANUFACTURER IDENTITY[11:1]” , AT91SAM7X128: JTAG ID Code value is 05B1_60 3F. 7354
647
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Version
6120H Comments
Change
Request
Ref.
Overview:
Table 3-1, “Signal Descrip tion List” footnote added to JTAGSEL, ERASE and TST pin comments.
Section 6.1 ”JTAG Port Pins”, Section 6.2 ”Test Pin” and Section 6.4 ”ERASE Pin”, updated. 5064
Section 8.4.3 ”Internal Flash”, updated: “At any time, the Flash is mapped ... if GPNVM bit 2 is set and before the
Remap Command.” 5850
Figure 9-1,”System Controller Block Diagram”, RTT is reset by power_on_reset. 5223
”Features”, ”Debug Unit (DBGU)”, added ”Mode for General Purpose 2-wire UART Serial Communi cation” 5846
ADC:
Section 35.6.2 ”ADC Mode Register”, PRESCAL and STARTUP bit fields widened.
“SHTIM: Sample & Hold Time” on page 473 formula updated in bit description.
Figure 35-1,”Analog-to-Digital Converter Block Diagram”, VDDANA re placed by VDDIN. PMC added to figure.
Figure 35.5.5,”Conversion Triggers”, update to the third paragraph detailing hardware trigger.
4430
5254
rfo
AIC:
Section 23.8.16 ”AIC Spurious Interrupt Vector Registe r ”, typo fixed in bit fields. (SIQV is SIVR).
Section 23.7.5 ”Protect Mode”, writing PROT in AIC_DCR enables protection mode (3rd paragraph). 4749
5193
CAN:
Section 36.6.4.6 ”Error Interrupt Handler”, added to datasheet.
Section 36.8.5 ”CAN Status Register”, added references to the new chapter in bi t descriptions, WARN, BOFF,
ERRA, ERP.
4736
DBGU:
Section 26.1 ”Overview”, ...” two-pin UART can be used standalone for ge neral purpose serial communication.” 5846
FFPI:
Section 20.2 ”Parallel Fast Flash Programming”, Section 20.2.1 ”Device Configuration”, added status of PIOs
and Crystal Oscillator
Section 20.3 ”Serial Fast Flash Programming”, Section 20.3.1 ”Device Configuration”, added status of PIOs and
Crystal Oscillator
5989
PMC:
”PMC System Clock Enable Register”, ”PMC System Clock Disable Register” and ”PMC System Clock Status
Register”, bit field 11 contains PCK3. 5722
PWM:
Section 33.6.12 ”PWM Channel Counter Register”, typos corrected in bit description. 5185
RSTC:
Section 13.2.4.4 ”Software Reset”, PERRST must be used with PROCRST, except fo r debug purposes.
SSC:
Section 31.8.3 ”SSC Receive Clock Mode Register”, corrected bit name to STTDLY.
648
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
UDP:
Section 34.6 ”USB Device Port (UDP) User Interface”, reset value for UDP_RST_EP is 0x000_0000.
Table 34-1, “U SB Endpoint Description”, footnote added to Dual-Bank heading.
Section 34.5.2.5 ”Transmit Data Cancellation”, added to datasheet
Section 34.6.9 ”UDP Reset Endpoint Register”, added steps to clear endpoints.
5049
5150
Electrical Characteristics:
Table 38-2, “D C Characteristics” , CMOS conditions added to IO for VOL and VOH.
Table 38-16, “External Voltage Reference Input”, added ADVREF inp ut w/conditions “8-bit resolution mode”. rfo
Mechanical Characteristics:
Table 39-1, “100-lead LQFP Package Dimensions”, Symbol line A, Inch Ma x value is 0.063 5608
Ordering Information:
Section 40. ”AT91SAM7X Ordering Information”, MLR B parts added to ordering information. 6064
Errata:
Section 41.5 ”AT91SAM7X256/128 Errata - Rev. B Parts”, added to errata.
Section 41.4.3.1 ”EFC: Embedded Flash Access Time”, added to SAM7X512 erraa.
Section 41.4.8.7 ”SPI: Software Reset must be Written Twice” added to errata.
USART: XOFF Character Bad Behavior, removed fro m errata.
6064
5989
5786
5338
Version
6120H
(Continued) Comments
Change
Request
Ref.
649
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Version
6120G Comments
Change
Request
Ref.
Overview,
“Features” , TWI updated to include Atmel TWI compatibility with I2C Standard.
Section 7.4 ”Peripheral DMA Controller” updated with PDC priorities.
Section 10.8 ”Two-wire Interface”, updated.
Section 10.11 ”Timer Counter” The TC has Two output compare or one input capture per channel.
Section 10.15 ”Analog-to-Digital Conver ter” INL and DNL updated.
4247
4774
4210
4007
CAN, Figure 36-7,”Line Error Mode” Conditions to switch from Error Active mode to Error Passive mode and vice
versa have been inverted. 4089
Debug and Test,
Section 12.5.5 ”ID Code Register”, product part numbers and JTAG ID code values updated . 4382
DBGU,
Section 26.5.10 ”Debug Unit Chip ID Register”, SRAM bit description added for AT91SAM7L in the bit field.
“SRAMSIZ: Internal SRAM Size” on page 216
Corrected bin values for 0x60 and 0xF0 and Architecture Identifier bit description for CAP7, AT9 1SAM7AQxx
Series and CAP11 in the bit description, “ARCH: Architecture Identifier” on page 217
3828
3369,
3807
EMAC,
Section 37.5.3 “Network Status Register ” on page 553, Corrected status for IDLE bit.
Section 37.3 “Functional Description” on page 536, Added information on clocks in first paragraph. 3326
3328
FFPI,
Table 20-6, Table 20-9, Table 20-18 updated
Global update to terms listed below:
Fuse → GPNVM
SFB → SGPB
CFB → CGPB
GFB → GGPB
Section 20.2.5.6 on page 119 & Section 20.3.4.6 on page 126, security bit restraint on access to FFPI explained.
4410
3933
4744
PIO,
Section 27.4.5 “Synchronous Data Output” on page 223, PIO_OWSR typo corrected.
Section 27.6 “Parallel Input/Outpu t Controller (PIO) User Interface” on page 227, 10, footnotes updated on
PIO_PSR, PIO_ODSR, PIO_PDSR in Register Mapping table.
3289
3974
PMC,
Section 25.3 ”Processor Clock Controller” ....the processor clock can be disabled by writing.... PMC_SDR.
Figure 24-2,”Typical Crystal Connection” updated, removed CL1 and CL2 labels. 3835
3861
PWM,
Section 33.6 “Pulse Width Modulation Controller (PWM) User Interface” on page 415, the Offset column in Table
33-2, Register Mapping ; the PWM channel-dependent registers listed as indexed registe r s.
See Section 33.6.9 ”PWM Channel Mode Register”, Section 33.6.10 ”PWM Channel Duty Cycle Register”,
Section 33.6.11 ”PWM Channel Period Regi ster”, Section 33.6.12 ”PWM Channel Counter Register”, and
Section 33.6.13 ”PWM Channel Update Regi ster”;
4486
650
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
SPI,
Section 28.6.4 “SPI Slave Mode” on page 254, corrected information on OVRES (SPI_SR) and data read in
SPI_RDR. 3943
SSC,
Section 31.6.5.1 ”Frame Sync Data”, defined max Frame Sync Data length.
Section 31.6.6.1 ”Compare Functions”, update d with max FSLEN length. 2293
TC,
Figure 32-2,”Clock Chaining Selection”, added to Section 32.5 ”Functional Description”.
Section 32.6 ”Timer Counter (TC) User Interface” Register mapping tables consoli dated in Table 32-4 on page
389 and register offsets ind exed.
Section 32.6.3 on page 392 to Section 32.6.13 on page 406 , register names updated with indexed offset.
Section 32.6.4 ”TC Channel Mode Registe r: Capture Mode” bit field 15 and W AVE bit field description updated.
3342
4583
TWI,
“Two-wire Interface (TWI)” , section has been updated.
Important changes to this datasheet include a clarification of Atmel TWI compatibility with I2C Standard. 4247
UDP,
Table 34-2, “USB Communication Flow”, Supported Endpoint column updated.
In the USB_CSR register, the control endpoints are not effected by the bit field, “EPEDS: Endpoint Enable
Disable” on page 475
Updated: write 1 =.... in “RX_DATA_BK0: Rece ive Data Bank 0” bit field of USB_CSR register.
Updated: write 0 = ....in “TXPKTRDY: Transmit Packet Ready” bit field of USB_CSR register.
Section 34.6.10 “UDP Endpoint Control and Status Register” on page 457, update to code and adde d
instructions regarding USB clock and system clock cycle, and updated “note” appearing under the code.
“wait 3 USB clock cycles and 3 system clock cycles before accessing DPR from RX_DATAx and TXPKTRDY bit
fields, ditto for RX_DATAx and TXPKTRDY bit field descriptions.”
Section 34.2 ”Block Diagram”, in the text below the block diagram, MCK specified as clock used by Master Clock
domain, UDPCK specified as 48 MHz clo ck used by 12 MHz domain, in peripheral clock requirements.
Section 34.6 ”USB Device Port (UDP) User Interface”, The register mapping table has been updated
Section 34.6.6 ”UDP Interrupt Mask Register” Bit 12 of has been defined as BIT12 and cannot be masked.
3476
4063
4099
4462
4487
4508
4802
USART,
“CLKO: Clock Output Select” on page 323, bit field in US_MR register, typo fixed in bit field description.
“USCLKS: Clock Selection” on pa ge 321, bit field in US_MR register, DIV= 8 in Selected Clock column.
Section 30.5.1 ”I/O Lines”, 2nd and 3rd paragraphsupdated.
“TXEMPTY: Transmitter Empty” on page 328, no ch aracters when at 1 updated.
Section 30.6.2 ”Receiver and Tran smitter Control”, In the fourth paragraph, Software reset effects (RSTRX and
RSTTX in US_CR register) updated by replacing 2nd sentence.
Section 30.6.5 ”IrDA Mode”, updated with instructi on to receive IrDA signals.
Section 30.2 ”Block Diagram”, signal directions from pads to PIO updated in the block diagram.
3306
3763
3851/4285
3895
4367
4912
4905
Version
6120G
(Continued) Comments
Change
Request
Ref.
651
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Electrical Characteristics,
Table 38-6, “Power Consumption for Different Modes”; Active mode consumption values updated. Footnote
assigned to Flash In standby mode. Footnote assigned to Ultra Low Power mode.
Section 38.7 ”ADC Characteristics”, INL and DN updated and Absolute accuracy added to Table 38-18,
“Transfer Characteristics”, reference to Data Converter Terminology added below table.
Table 38-9, “Main Oscillator Characteristics”, added schematic in footnote to CL and CLEXT symbols.
Table 38-11, “XIN Clock Electrical Characteristics”, added tCLCH and tCHCL to table, tCHXIN and tCLXIN updated.
Figure 38-2, ”XIN CLock Timing” on page 588, added figure.
Table 38-2, “DC Characteristics”, removed refe rence to Tj
Section 39.1 “Thermal Cond itions”, removed.
Table 39-3, “Package Reference” JESD97 Classification changed to e3.
4596/
4597
4007
3866
3967
4659
4968
Errata,
“AT91SAM7X256/128 Errata - Rev. A Parts” :
Section 41.3.2 “Controller Area Network (CAN)” on page 612, added
Section 41.3.10.1 ”USART: CTS in Hardware Handshaking”, updated.
Section 41.3.10.3 “USART: RXBRK Flag Error in Asynchronous Mode” on page 617, added.
Section 41.3.10.4 “USART: DCD is Active High instead of Low.” on page 617, added.
Section 41.3.1 “Analog-to-Digital Converter (ADC)” on page 610, added
Section 41.3.7.6 “SPI: Bad Serial Clock Genera tion on 2nd Chip Select” on page 615, added
“AT91SAM7X512 Errata - Rev. A Parts” :
Section 41.4.2 “Controller Area Network (CAN)” on page 620, added
Section 41.4.11.1 ”USART: CTS in Hardware Handshaking”, updated.
Section 41.4.11.3 “USART: RXBRK Flag Error in Asynchronous Mode” on page 625, added
Section 41.4.11.4 “USART: DCD is Active High instead of Low.” on page 625, added
Section 41.4.1 “Analog-to-Digital Converter (ADC)” on page 618, added
Section 41.4.8.6 “SPI: Bad Serial Clock Genera tion on 2nd Chip Select” on page 623, added
4648
3956
4645
4750
4648
3956
4645
4750
Version
6120G
(Continued) Comments
Change
Request
Ref.
652
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Version
6120F Comments
Change
Request
Ref.
AT91SAM7X512 added to product family. “Features” on page 2, “Configuration Summary of the
SAM7X512/256/128” on page 4 Global and TFBGA package to Section 4. ”Package”, Section 39.
”SAM7X512/256/128 Mechanical Characteristics” and Section 40. ”AT91SAM7X Ordering Information”.
Section 4.1 ”100-lead LQFP Package Outline” and Section 4.3 ”100-ball TFBGA Pa ckage Outlin e” Replace
“...Mechanical Overview”
Peripheral and System Controller Memory Maps consolidated in Figure 8-1 on page 18
Internal Memory Area 3 is “Internal ROM” Figure 18-3 on page 92
#2724
Section 10.1 ”User Interface” User Peripherals are mapped between 0xF000 0000 and 0XFFFF EFFF.
Table 10-1 on page 30 SYSIRQ changed to SYSC in “Peripheral Identifiers”. rfo review
IP Block Evolution:
RSTC: Section 13.2 “Functional Description” on page 56, added information on startup counter for crystal
oscillator. 3005
RTT: Section 14.3 ”Functional Description”: Note (asynchronization between SCLK and MCK) added to end
of section. 2522
WDT: “Block Diagram” on page 82 replaced. (WV chan ged to WDV) “Functional Description” on page 83
6th and 7th paragraph changed. 3002
EFC: Section 19. ”Embedded Flash Controller (EFC)” updated to reflect EFC configuration for
AT91SAM7X512 with multiple EFCs. 2356
3086
FFPI: information added to Section 20.2.5.6 and Section 20.3.4.6 ”Flash Security Bit Command”, added
Section 20.2.5.7 and Section 20.3.4.7 ”AT91SAM7X 512 Select EFC Command” rfo/2284
AT91SAM Boot Program: “Hardware and Software Constraints” on page 133 SAM7X512 added
“SAM-BA Boot” on page 129, SAM-BA boot principle changed
“Flow Diagram” on page 128 replac ed Figure 21-1
2285/2618
3050
PDC: Corrected description of user interface in Section 22.1 “Overvie w” on pag e 134.
Corrected bit name to ENDTX in Se ction 22.3.3 “Transfer Counters” on page 135 . 05-460
AIC: Section 23.7.3.1 “Priority Controller” on page 149: incorrect reference of SRCTYPE field to AIC_SVR
register changed to AIC_SMR register.
Section 23.8 “Advanced Interrupt Controller (AIC) User Interface” on page 157, Table 23-2: Added note (2)
in reference to PID2...PID31 bit fields.
Naming convention for AIC_FVR register harmonized in Ta ble 23-2, Section 23.8.6 “AIC FIQ Vector
Register” on page 160 and Section 23.7.4. 5 “Fa st Fo rci n g” on page 153.
2512
2548
PMC: Section 25.7 “Programming Sequence” on page 174 change to Step 4. on page 175, “Selection of
Master Clock and Processor Clock” and to code.
Corrected name of bitfield PRES in Section 25.9.10 “PMC Master Clock Register” on page 189.
Removed reference to PMC_ACKR register in Table 25-2, “Register Mapping,” on page 180.
Updated OUTx bit descriptions in Section 25.9.9 “PMC Clock Generator PLL Register” on page 188.
Added note defining PIDx in Section 25.9.4 “PMC Peripheral Clock Enable Register” on page 184, Section
25.9.5 “PMC Peripheral Clock Disable Register” on page 184 and Section 25.9.6 “PMC Peripheral Clock
Status Register” on page 185.
Changed Section 24.2 “Slow Clock RC Oscillator” on page 168.
05-506
1603
1719
2467, 2913
2468
1558
653
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
DBGU: Corrected references from ice_nreset to Power-on Reset in Fi gu re 26-1 on page 196 , Func tional
Block Diagram, and in FNTRST bit de scription in Section 26.5.12 “Debug Unit Force NTRST Register” on
page 218.2832
PIO:Section 27.4.4 “Output Control” on page 222, typo corrected
Section 27.4.1 “Pull-up Resistor Control” on page 221 reference to resistor value removed.
Figure 27-3 on page 221 0 and 1 inverted in the MUX contro lled by PIO_MDSR..
05-346
05-497
3053
SPI: Section 28.7.5 “SPI Status Register” on page 262 SPI_RCR, SPI_RNCR, SPI_TCR, SPI_TN CR
location defined.
Section 28.7.4 “SPI Transmit Data Register” on page 261, LASTXFER: Last Transfer text added.
Section 28.7.2 “SPI Mode Register” on page 258, PCSDEC: Chip Select Decode changed.
Updated Figure 28-1, ”Block Diagram” on page 244, removed Note. Removed bit FDIV from Section 28.7.2
“SPI Mode Register” on page 258 and Section 28.7.9 “SPI Chip Select Register” on page 267. LLB
description modified in Section 28.7.2 “SPI Mode Register” on pag e 258.
Updated Figure 28-9 , ”Slave Mode Functional Block Diagram” on page 255 to remove FLOAD.
Updated information on SPI_RDR in Section 28.6.3 “Master Mode Oper ations” on page 249. Added
information to SWRST bit description in Section 28.7.1 “SPI Control Register” on page 257. Corrected
equations in DLYBCT bit description, Section 28.7.9 ”SPI Chip Select Register” on page 268.
Changes to Section 28.6.3.8 “Mode Fault Detection” on page 254.
04-183
05-434
05-476
05-484
1542
1543
1676
USART:
Manchester Functionality Removed.
Section 30.4 “I/O Lines Description” on page 293, text concerning TXD line added.
Section 30.6.1.3 “Fractional Baud Rate in Asynchronous Mode” on pa ge 297, using USART “functional
mode” changed to USART “normal mode”.
Table 30-3, “Binary and Decimal Values for Di,” on page 298 and Table 30-4, “Binary and Decimal Values
for Fi,” on page 299: DI and Fi properly referenced in titles.
Figure 30-25, ”IrDA Demodulator Operations” on page 314 modified.
Section 30.6.4.1 “ISO7816 Mode Overview” on page 310 clarification of PAR configuration added.
Section 30.6.7 “Modem Mode” on page 316 Control of DTR an d RTS outp u t pi n s .
Table 30-2, “Baud Rate Exa mp le (OVER = 0),” on page 296 60k and 70k MHz clock speeds removed.
“Asynchronous Receiver” on page 301 2nd line in 4th paragraph changed.
“Receiver Time-out” on page 306 list of user options rewritten.
Section 30.7.1 ”USART Control Register” STTTO bit function relate d to TIMEOUT in US_CSR register
Section 30.7.6 ”USART Channel Status Register” TIMEOUT bit function related to STTO in US_CR register
2768
1552
1770
2942
3023
TC: Section 32.5.12 “External Event/Trigger Conditions” on page 388 “....(EEVT = 0), TIOB is no longer
used as an output and the compare register B is not used to genera te waveforms and subsequently no
IRQs. Note (1) attached to ”EEVT: External Event Selection” in Section 32.6.5 “TC Channel Mode Register:
Waveform Mode” on page 395 fu rther clarifies this condition.
2704
PWM: Section 33.5.3.3 ”Changing the Duty Cycle or the Period”: updated info on waveform generation. 1677
Version
6120F
(Continued) Comments
Change
Request
Ref.
654
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Section 34. “USB Device Port (UDP)” on page 441: Corrections, impro veme nts, additions and deletions
throughout section, new source document.
Section 34.5.3.8 ”Sending a Device Remote Wakeup” replaces title “Sending an External Resume.
WAKEUP bit shown in interruput registers: Section 34.6.4 on page 450 thru Section 34.6.8 on page 455
RMWUPE, RSMINPR, ESR bits removed from Section 34.6.2 ”UDP Global State Register”
NOTE: pertinent to USB pullup effect on USB Reset added to Section 34.6.12 ”UDP Transceiver Control
Register”.
3288
ADC: Section 35.2 “Block Diagram” on page 46 3 dedicated and I/O line multiplexed inpu ts differentiated.
“ADC Timings” on page 486 typo corrected in warning
3052
2830
CAN: Update to message acceptance example in Sectio n 36.6.2.1 “Message Acceptance Procedure” on
page 484.
New information on byte priority added to Section 36.8.17 “CAN Message Data Low Register” on page 531
and Section 36.8.18 “CAN Message Data High Register” on page 532.
Corrected MDL bit description in Section 36.8.17 “CAN Message Data Low Register” on page 531.
Update to specify allowed values for BRP field on Section 36.6.4 ”CAN 2.0 Standard Features”, page 48 9
and in Section 36.8.6 “CAN Baudrate Register” on page 518.
2295, 2296
2476
2597
EMAC: “Interrupt Enable Register” on page 559, access changed to Write-only.
“Interrupt Disable Register” on page 560, access chang ed to Write-only.
“Interrupt Mask Register” on page 561, access changed to Read-only. 1725
Section 38. ”SAM7X512/256/128 Electrical Characteristics”
“Absolute Maximum Ratings” on page 581 change to Maximu m Operating Voltages 3059
Changed conditions of parameters IPULLUP and ILEAK in Table 38-2, “DC Characteristics,” on page 582.
Updated Table 38-5, “DC Flash Characteristics SAM7X512/2 56/128,” on page 583 and Table 38-9, “Main
Oscillator Characteristics,” on page 587.
Added Table 38-10, “Crystal Characteristics,” on page 588.
Updated IDDBP in Table 38-11, “XIN Clock Electrical Characteristics,” on page 588.
Added information on data sampling in SPI master mode to Table 38-21, “SPI Timings,” on page 595.
Updated Table 38-22, “EMAC Signals,” on page 596
Added Table 3 8-24, “EMAC RMII Specific Signals (Only for SAM7X512),” on page 598 and Figure 38-9,
”EMAC RMII Mode” on page 598.
rfo review
Errata updated:
Added Section 41.1 “Marking” on page 607.
Section 41.3.6.1 ”RTT: Possible Event Loss when Reading RTT_ SR”
Section 41.3.7.4 ”SPI: Chip Select and Fixed Mode”
Section 41.3.7.5 ”SPI: Baudrate Set to 1”
TWI: Behavior of OVRE Bit (removed)
Section 41.3.9.5 ”TWI: Software Reset”
Section 41.3.10.2 ”USART: Hardware Handshaking – Two Characters Sent”
Section 41.3.10.3 ”USART: RXBRK Flag Error in Asynchronous Mode”
#2871
PIO: Leakage on PB27 - PB 30 ....”the leakage can be 25 µA in worst case...” rfo review
Version
6120F
(Continued) Comments
Change
Request
Ref.
655
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Version Comments
Change
Request
Ref.
6120E 04-Apr-06
The following errata have been added:
Section 41.3.3.2 ”EMAC: Possible Event Loss when Reading EMAC_ISR”
Section 41.3.3.3 ”EMAC: Possible Event Loss when Reading the Statistics Register Block”
Section 41.3.7.3 ”SPI: SPCK Behavior in Master Mode”
Section 41.3.4.1 ”PIO: Leakage on PB27 - PB30”: worst case lea kage changed to 9 µA
#2455
#2605
6120D 03-Feb-06
Section 41. ”SAM7X512/256/128 Errata”
Device package/product number changed
Section 41.3.3 ”Ethernet MAC (EMAC)” RMII mode is not functional
The sections listed below have been added to the Errata:
Section 41.3.5 ”Pulse Width Modulation Controller (PWM)”
Section 41.3.7 ”Serial Peripheral Interface (SPI)”
Section 41.3.8 ”Synchronous Serial Controller (SSC)”
Section 41.3. 9 ”Two-wire Interface (TWI)”
Section 41.3.10 ”Universal Synchronous Asynchronous Receiver Transmitter (USART)”
#1767
6120C 26-Oct-05
Replaced Section 29. “Two-wire Interface (TWI)” on page 269. 05-516
6120B 17-Oct-05
Updated product functionalities in “Features” on page 2, Figure 2-1 on page 5, Section 9.5 “Debug Unit”
on page 28, and Figure 11-1 on page 27 05-456
Corrected PLL output range maximum value in Section 9.2 “Clock Generator” on page 26, Figure 18-3 in
Section 18.3.2.1 “Internal Memory Mapping” on page 91 and Table 38-12, “Phase Lock Loop
Characteristics,” on page 589.05-491
Updated information in Power Supplies on page 9
Updated field Part Number in Section 12.5.5 “ID Code Register” on page 54.
Updated Chip ID in Section 9.5 “Debug Unit” on page 28 and in Section 12.5.3 “Debug Unit” on page 47. 05-472
Removed references to PGMEN2 in Section 20. “Fast Flash Programming Interface (FFPI)” on page 113. 05-464
Updated “ARCH: Architecture Identifier” in Debug Unit with new values for AT91SAM7XCxx series and
AT91SAM7Xxx series. 05-459
Updated CAN bit timing configur ation in Section 36.6.4.1 “CAN Bit Timing Configuration” on page 488
and in Section 36.8.6 “CAN Baudrate Register” on page 518. 05-419
Added Section 38.8.4 “EMAC Characteristics” on page 596 . 05-469
Updated AT9 1SAM7X Ordering information . 05-470
6120A 10-Oct-05 First issue
656
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Table of Contents
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1. Configuration Summary of the SAM7X512/256/128 . . . . . . . . . . . . . 4
2. SAM7X512/256/128 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1 100-lead LQFP Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2 100-lead LQFP Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3 100-ball TFBGA Package Outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.4 100-ball TFBGA Pinout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5. Power Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Power Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2 Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3 Voltage Regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.4 Typical Powering Schematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. I/O Lines Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1 JTAG Port Pins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.2 Test Pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.3 Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.4 ERASE Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.5 PIO Controller Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.6 I/O Lines Current Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7. Processor and Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.1 ARM7TDMI Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.2 Debug and Test Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.3 Memory Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.4 Peripheral DMA Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8. Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1 SAM7X512 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2 SAM7X256 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.3 SAM7X128 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.4 Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.5 Embedded Flash. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.6 Fast Flash Programming Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.7 SAM-BA Boot Assistant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9. System Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.1 Reset Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.2 Clock Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9.3 Power Management Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.4 Advanced Interrupt Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.5 Debug Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
657
SAM7X Series [DATASHEET]
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9.6 Periodic Interval Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.7 Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.8 Real-time Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.9 PIO Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.10 Voltage Regulator Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
10. Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.1 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.2 Peripheral Identifiers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.3 Peripheral Multiplexing on PIO Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.4 PIO Controll er A Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.5 PIO Controll er B Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
10.6 Ethernet MAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10.7 Serial Peripheral Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10.8 Two-wire Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10.9 USART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.10 Serial Synchronous Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.11 Timer Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.12 Pulse Width Modulation Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.13 USB Device Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.14 CAN Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.15 Analog-to-Digital Converter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11. ARM7TDMI Processor Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
11.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
11.2 ARM7TDMI Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
12. Debug and Test Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
12.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
12.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
12.3 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
12.4 Debug and Test Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
12.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
13. Reset Controller (RSTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
13.1 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
13.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
13.3 Reset Controller (RSTC) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
14. Real-time Timer (RTT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
14.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
14.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
14.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
14.4 Real-time Timer (RTT) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
15. Periodic Interval Timer (PIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
15.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
15.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
15.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
15.4 Periodic Interval Timer (PIT) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 77
16. Watchdog Timer (WDT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
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SAM7X Series [DATASHEET]
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16.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
16.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
16.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
16.4 Watchdog Timer (WDT) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
17. Voltage Regulator Mode Controller (VREG) . . . . . . . . . . . . . . . . . . 88
17.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
17.2 Voltage Regulator Power Con troller (VREG) User Interface . . . . . . . . . . . . . 89
18. Memory Controller (MC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
18.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
18.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
18.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
18.4 Memory Controller (MC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
19. Embedded Flash Controller (EFC) . . . . . . . . . . . . . . . . . . . . . . . . . . 99
19.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
19.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
19.3 Embedded Flash Controller (EFC ) User Interface. . . . . . . . . . . . . . . . . . . . 107
20. Fast Flash Programming Interface (FFPI) . . . . . . . . . . . . . . . . . . . 113
20.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
20.2 Parallel Fast Flash Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
20.3 Serial Fast Flash Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
21. AT91SAM Boot Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
21.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
21.2 Flow Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
21.3 Device Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
21.4 SAM-BA Boot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
21.5 Hardware and Software Constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
22. Peripheral DMA Controller (PDC) . . . . . . . . . . . . . . . . . . . . . . . . . 134
22.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
22.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
22.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
22.4 Peripheral DMA Controller (PDC) User Interface . . . . . . . . . . . . . . . . . . . . . 136
23. Advanced Interrupt Controller (AIC) . . . . . . . . . . . . . . . . . . . . . . . . 143
23.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
23.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
23.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
23.4 AIC Detailed Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
23.5 I/O Line Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
23.6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
23.7 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
23.8 Advanced Inte rrupt Controller (AIC) User Interface . . . . . . . . . . . . . . . . . . . 157
24. Clock Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
24.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
24.2 Slow Clock RC Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
24.3 Main Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
24.4 Divider and PLL Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
659
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
25. Power Management Controller (PMC) . . . . . . . . . . . . . . . . . . . . . . 172
25.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
25.2 Master Clock Controll er . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
25.3 Processor Clock Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
25.4 USB Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
25.5 Peripheral Clock Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
25.6 Programmable Clock Output Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
25.7 Programming Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
25.8 Clock Switching Details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
25.9 Power Management Controller (PMC) User Interface . . . . . . . . . . . . . . . . . 180
26. Debug Unit (DBGU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
26.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
26.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
26.3 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
26.4 UART Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
26.5 Debug Unit (DBGU) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
27. Parallel Input/Output Controller (PIO) . . . . . . . . . . . . . . . . . . . . . . 219
27.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
27.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
27.3 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
27.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
27.5 I/O Lines Programming Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
27.6 Parallel Input/Output Controller (PIO) User Interface . . . . . . . . . . . . . . . . . . 227
28. Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . 244
28.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
28.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
28.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
28.4 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
28.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
28.6 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
28.7 Serial Peripheral Interface (SPI) User Interface . . . . . . . . . . . . . . . . . . . . . . 256
29. Two-wire Interface (TWI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
29.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
29.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
29.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
29.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
29.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
29.6 TWI User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
30. Universal Syn chronous Asyn chronous Re ceiver Transceiver (USART)
291
30.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
30.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
30.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
30.4 I/O Lines Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
30.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
30.6 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
30.7 Universal Synchronous Asynchronous Receiver Transeiver (USART) User Inter-
660
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
face . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
31. Synchronous Serial Controller (SSC) . . . . . . . . . . . . . . . . . . . . . . 337
31.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
31.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
31.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
31.4 Pin Name List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
31.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
31.6 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
31.7 SSC Application Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
31.8 Synchronous Serial Controller (SSC) User Interface . . . . . . . . . . . . . . . . . . 351
32. Timer Counter (TC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
32.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
32.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
32.3 Pin Name List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
32.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
32.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
32.6 Timer Counter (TC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
33. Pulse Width Modulation Controller (PWM) . . . . . . . . . . . . . . . . . . 407
33.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
33.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
33.3 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
33.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
33.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
33.6 Pulse Width Modulation Controller (PWM) Us er Interface . . . . . . . . . . . . . . 415
34. USB Device Port (UDP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
34.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
34.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
34.3 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
34.4 Typical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
34.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
34.6 USB Device Port (UDP) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
35. Analog-to-Digital Converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . 463
35.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
35.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
35.3 Signal Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
35.4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
35.5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
35.6 Analog-to-Digital Conver ter (ADC) User Interface . . . . . . . . . . . . . . . . . . . . 470
36. Controller Area Network (CAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
36.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
36.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
36.3 Application Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
36.4 I/O Lines Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
36.5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
36.6 CAN Controller Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
36.7 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
661
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8 Controller Area Network (CAN) User Interface . . . . . . . . . . . . . . . . . . . . . . 506
37. Ethernet MAC 10/100 (EMAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
37.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
37.2 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
37.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
37.4 Programming Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545
37.5 Ethernet MAC 10/100 (EMAC) User Interface . . . . . . . . . . . . . . . . . . . . . . . 548
38. SAM7X512/256/128 Electrical Characteristics . . . . . . . . . . . . . . . 581
38.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
38.2 DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582
38.3 Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584
38.4 Crystal Oscillators Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586
38.5 PLL Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589
38.6 USB Transceiver Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
38.7 ADC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
38.8 AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593
39. SAM7X512/256/128 Mechanical Characteristics . . . . . . . . . . . . . . 602
39.1 Package Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
39.2 Soldering Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
40. AT91SAM7X Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . 606
41. SAM7X512/256/128 Errata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
41.1 Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
41.2 Errata Summary by Product and Revision or Manufacturing Number . . . . . 608
41.3 AT91SAM7X256/128 Errata - Rev. A Parts . . . . . . . . . . . . . . . . . . . . . . . . . 610
41.4 AT91SAM7X512 Errata - Rev. A Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
41.5 AT91SAM7X256/128 Errata - Rev. B Parts . . . . . . . . . . . . . . . . . . . . . . . . . 626
41.6 AT91SAM7X512 Errata - Rev. B Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
41.7 AT91SAM7X256/128 Errata - Rev. C Parts . . . . . . . . . . . . . . . . . . . . . . . . . 642
42. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
Atmel Corporation
1600 Techno logy Drive
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Tel: (+1) (408) 441-0311
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Atmel Asia Limit ed
Unit 01-5 & 16 , 19F
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JAPAN
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© 2014 Atmel Corporation. All rights reserved. / Rev.: 6120K–ATARM–11-Feb-14
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