AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 222

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

26.4.6
26.4.7
Figure 26-11. Test Modes
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:
Returns the debug communication data read register into Rd
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 gener-
ate an interrupt. This feature permits handling under interrupt a debug link between a debug monitor running on the
target system and a debugger.
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:
Debug Communication Channel Support
Chip Identifier
MRC
MCR
p14, 0, Rd, c1, c0, 0
p14, 0, Rd, c1, c0, 0
Remote Loopback
Automatic Echo
Local Loopback
Transmitter
Transmitter
Transmitter
Receiver
Receiver
Receiver
V
DD
Disabled
Disabled
Disabled
Disabled
Disabled
V
DD
SAM7S Series [DATASHEET]
RXD
TXD
RXD
TXD
TXD
RXD
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