BAT32G1x9 user manual | Chapter 22 CAN control
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Rev.1.02
< 4> data farm
The data farm contains the amount of data, in bytes, that controls the field settings. Up to 8 data
units can be set.
Figure 22-9. Data farm
(control fields)
(Data fields)
(CRC fields)
Data 0
(8 bit)
Data 7
(8 bit)
Note D: Dominant
=0
R: Recessive = 1
<5>CRCfield
A CRC field is a 16-bit field that detects errors in data transmission.
Figure 22-10. CRC field
(Data fields or
control fields)
(CRC fields)
(ACK fields)
CRC delimiter
CRC Sequence
(15 bit)
(1 bit)
Note D: Dominant = 0
R: Recessive = 1
- The polynomial P(X) used to generate a 15-bit CRC sequence is represented as follows:
- P(X)=X
15
+X
14
+X
10
+X
8
+X
7
+X
4
+X
3
+1
- Send Node:
Sends a sequence of CRC calculations for data from the start frame, arbitration field, control
field, and data farm (before bit population
).
- Receive Node:
Compares the computed CRC sequence with the data bit in the CRC field using the
data bits that exclude the padding bits in the received data. If the two CRC sequences do not
match, the node issues an error frame.
