Figure 236. Can Frames - ST STM32F40 Series Reference Manual

RM0090

Figure 236. CAN frames

Data Frame or
Remote Frame
End Of Frame or
Error Delimiter or
Overload Delimiter
Inter-Frame Space
Arbitration Field
32
ID
Inter-Frame Space
Arbitration Field
32
ID
Inter-Frame Space
Arbitration Field
32
ID
Error Frame
Error
Flag Echo Error Delimiter
Flag
6
6
Any Frame Inter-Frame Space
Suspend
Intermission Bus Idle
Transmission
3
8
Overload Frame
Overload Overload
Flag Echo
6
6
Doc ID 018909 Rev 4
Data Frame (Standard identifier)
44 + 8 * N
Ctrl Field Data Field CRC Field
6 8 * N
DLC
Data Frame (Extended Identifier)
64 + 8 * N
Ctrl Field Data Field
Arbitration Field
32 6 8 * N
DLC
Remote Frame
44
Ctrl Field CRC Field
6 16
DLC CRC
Inter-Frame Space
or Overload Frame
8
Data Frame or
Remote Frame
Inter-Frame Space
or Error Frame
Overload
Delimiter
8
Controller area network (bxCAN)
Inter-Frame Space
or Overload Frame
Ack Field
2
16 7
CRC EOF
Inter-Frame Space
or Overload Frame
CRC Field Ack Field
2
16 7
CRC EOF
Inter-Frame Space
or Overload Frame
Ack Field
2
7
EOF
Notes:
0 <= N <= 8
SOF = Start Of Frame
ID = Identifier
RTR = Remote Transmission Request
IDE = Identifier Extension Bit
r0 = Reserved Bit
DLC = Data Length Code
CRC = Cyclic Redundancy Code
Error flag: 6 dominant bits if node is error
active else 6 recessive bits.
Suspend transmission: applies to error
passive nodes only.
EOF = End of Frame
ACK = Acknowledge bit
Ctrl = Control
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