AT32UC3C2512C Automotive Atmel Corporation, AT32UC3C2512C Automotive Datasheet - Page 1231

• Manufacturer Part Number: AT32UC3C2512C Automotive
• Manufacturer: Atmel Corporation

9166C–AVR-08/11
The CRC is calculated from the command/response, length, and data fields. The polynomial
used is the FCS16 (or CRC-16-CCIT) in reverse mode (0x8408) and the starting value is
0x0000.
Example command
Below is an example command from the master with additional data.
Figure 39-9. Example Command
Example response
Below is an example response from the slave with additional data.
Figure 39-10. Example Response
Avoiding drive contention when changing direction
The aWire debug protocol uses one dataline in both directions. To avoid both the master and the
slave to drive this line when changing direction the AW has a built in guard time before it starts to
drive the line. At reset this guard time is set to maximum (128 bit cycles), but can be lowered by
the master upon command.
The AW will release the line immediately after the stop character has been transmitted.
baud_rate_clk
data_pin
field
...
baud_rate_clk
data_pin
field
...
sync(0x55)
data(MSB)
sync(0x55)
data(MSB)
command(0x81)
data(LSB)
response(0xC1)
data(LSB)
length(MSB)
CRC(MSB)
length(MSB)
CRC(MSB)
length(lsb)
CRC(lsb)
length(lsb)
CRC(lsb)
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