jani12
Advanced Member level 4
Camera ECU sends External Steering Request (XSR) J1939 message to the steering ECU. The PGN of this message is 0xF341. There is 4-bit checksum within the 8 byte data field. The SPN of this checksum is 21095.
This 4-bit checksum is used to verify the signal path from the demanding device to the active steering system. It is calculated using the first 7 data bytes, the 4 bit message counter and the bytes of the message identifier.
Since there is 16 Bit CRC Field in the J1939 frame (please see attached), why does J1939 specification include 4-bit checksum within the Data Field?
This 4-bit checksum is used to verify the signal path from the demanding device to the active steering system. It is calculated using the first 7 data bytes, the 4 bit message counter and the bytes of the message identifier.
Since there is 16 Bit CRC Field in the J1939 frame (please see attached), why does J1939 specification include 4-bit checksum within the Data Field?