AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 130

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

20.3.4
20.3.4.1
130
AT91SAM7X512/256/128 Preliminary
Device Operations
Flash Read Command
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 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 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.
Several commands on the Flash memory are available. These commands are summarized in
Table 20-3 on page
is reading and writing the Debug Comms Registers.
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
• Debug Comms Control Register: DCCR
• Debug Comms Data Register: DCDR
• The address of the Debug Comms Control Register is 0x04.
• The address of the Debug Comms Data Register is 0x05.
TDI
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
– Bit 0 (R): Denotes whether the programmer can send data from the Debug Comms
Comms Data Register. If the device is busy W = 0, then the programmer must poll
until W = 1.
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.
r/w
4
Address
Address
Decoder
121. Commands are run by the programmer through the serial interface that
5
0
31
Debug Comms Control Register
Debug Comms Data Register
Data
32
6120H–ATARM–17-Feb-09
0
TDO