CONTROLLER AREA NETWORK (bxCAN)
CONTROLLER AREA NETWORK (Cont’d)
Figure 153. CAN Frames
Inter-Frame Space
or Overload Frame
Inter-Frame Space
Data Frame (Standard identifier)
44 + 8 * N
Ack Field
2
Control Field Data Field
CRC Field
16
Arbitration Field
12
ID
6
8 * N
7
CRC
EOF
DLC
Inter-Frame Space
or Overload Frame
Inter-Frame Space
Data Frame (Extended Identifier)
64 + 8 * N
Std Arbitr. Field
12
Ext Arbitr. Field
20
Ack Field
2
Ctrl Field Data Field CRC Field
6
8 * N
16
7
ID
CRC
EOF
DLC
Inter-Frame Space
or Overload Frame
Inter-Frame Space
Remote Frame
44
Ack Field End Of Frame
Control Field
CRC Field
Arbitration Field
12
2
6
16
7
ID
CRC
DLC
Data Frame or
Remote Frame
Inter-Frame Space
or Overload Frame
Notes:
Error Frame
Flag Echo Error Delimiter
• 0 <= N <= 8
Error Flag
• SOF = Start Of Frame
• ID = Identifier
≤ 6
8
6
• RTR = Remote Transmission Request
• IDE = Identifier Extension Bit
• r0 = Reserved Bit
Data Frame or
Remote Frame
Any Frame
Intermission
Inter-Frame Space
Suspend
• 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.
Bus Idle
Transmission
8
3
End Of Frame or
Error Delimiter or
Overload Delimiter
Inter-Frame Space
or Error Frame
Overload Frame
• EOF = End of Frame
Overload Flag Overload Delimiter
• ACK = Acknowledge bit
6
8
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STMICROELECTRONICS [ ST ]
