AT32UC3L064-D3HES ATMEL [ATMEL Corporation], AT32UC3L064-D3HES Datasheet - Page 762

• Manufacturer Part Number: AT32UC3L064-D3HES
• Manufacturer: ATMEL [ATMEL Corporation]

Table 31-31. aWire Packet Format
32099D–06/2010
Field
LENGTH
DATA
CRC
Number of bytes
2
LENGTH
2
CRC calculation
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 31-9. Example Command
Example response
Below is an example response from the slave with additional data.
Figure 31-10. Example Response
baud_rate_clk
data_pin
field
...
baud_rate_clk
data_pin
field
...
Description
The number of bytes in the DATA
field.
Data according to command/
response.
CRC calculated with the FCS16
polynomial.
sync(0x55)
data(MSB)
sync(0x55)
data(MSB)
command(0x81)
data(LSB)
response(0xC1)
data(LSB)
Comment
CRC value of 0x0000 makes the aWire
disregard the CRC if the master does not
support it.
length(MSB)
CRC(MSB)
length(MSB)
CRC(MSB)
AT32UC3L016/32/64
length(lsb)
CRC(lsb)
length(lsb)
CRC(lsb)
Optional
Yes
Yes
No
...
...
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