National Semiconductor CP3BT26 User Manual page 113

A CAN data frame consists of the following fields:
Start of Frame (SOF)
Arbitration Field + Extended Arbitration
Control Field
Data Field
Cyclic Redundancy Check Field (CRC)
d
Note:
d = dominant
r = recessive
11
d
IDENTIFIER
28 ... 18
Note:
d = dominant
r = recessive
A remote frame is comprised of the following fields, which is
the same as a data frame (see CAN Frame Fields on page
111) except for the data field, which is not present.
Start of Frame (SOF)
Arbitration Field + Extended Arbitration
Control Field
Cyclic Redundancy Check Field (CRC)
Acknowledgment field (ACK)
End of Frame (EOF)
Note that the DLC must have the same value as the corre-
sponding data frame to prevent contention on the bus. The
RTR bit is "recessive".
STANDARD REMOTE FRAME (number of bits = 44)
Arbitration Field Control Field
11 4
d d d
IDENTIFIER
DATA
10 ... 0
LENGTH CODE
Figure 38. Standard Remote Frame
EXTENDED REMOTE FRAME (number of bits = 64)
Arbitration Field
18
r r
IDENTIFIER
17 ... 0
Figure 39. Extended Remote Frame
Acknowledgment Field (ACK)
End of Frame (EOF)
Remote Frame
Figure 38 shows the structure of a standard remote frame.
Figure 39 shows the structure of an extended remote frame.
16
CRC Field
15
CRC
r r r
16
Control Field CRC Field
4 15
CRC
r d d
DATA
LENGTH CODE
113
END OF
FRAME
r r r r r r
DS022
END OF
FRAME
r r r r r r r r r
DS023
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