1

I am trying to figure out a checksum algorithm. D1 to D6 is data, D7 is a counter obviously and byte 8 must be a CRC, but I didnt have any idea on how to build it. Tried to check if it fits any standard, but no clue yet. Would be awesome if anyone had an idea :)

    D1  D2  D3  D4  D5  D6  D7  D8
    20  0E  20  00  04  FF  F0  1F
    20  0E  20  00  04  FF  00  60
    20  0E  20  00  04  FF  10  AD
    20  0E  20  00  04  FF  20  E7
    20  0E  20  00  04  FF  30  2A
    20  0E  20  00  04  FF  40  73
    20  0E  20  00  04  FF  50  BE
    20  0E  20  00  04  FF  60  F4
    20  0E  20  00  04  FF  70  39
    20  0E  20  00  04  FF  80  46
    20  0E  20  00  04  FF  90  8B
    20  0D  20  00  04  FF  A0  0B
    20  0D  20  00  04  FF  B0  C6
    20  0D  1F  FF  04  FF  C0  6A
    20  0D  1F  FF  04  FF  D0  A7
    20  0D  1F  FE  04  FF  E0  70
    20  0C  1F  FD  04  FF  F0  41
    20  0C  1F  FD  04  FF  00  3E
    20  0C  1F  FC  04  FF  10  6E
    20  0B  1F  FB  04  FF  20  1F
    20  0B  1F  FB  04  FF  30  D2
    20  0B  1F  FB  04  FF  40  8B
    20  0A  1F  FA  04  FF  50  9D
    20  0A  1F  FA  04  FF  60  D7
    20  0A  1F  F9  04  FF  70  A0
    20  09  1F  F9  04  FF  80  15
    20  09  1F  F9  04  FF  90  D8
    20  09  1F  FA  04  FF  A0  28
    20  08  1F  F9  04  FF  B0  19
    20  08  1F  FA  04  FF  C0  FA
    20  08  1F  F9  04  FF  D0  8D
    20  07  1F  F8  04  FF  E0  9F
    20  07  1F  F8  04  FF  F0  52
    20  06  1F  F8  04  FF  00  6B
    20  05  1F  F7  04  FF  10  04
    20  05  1F  F7  04  FF  20  4E
    20  04  1F  F6  04  FF  30  58
    20  03  1F  F5  04  FF  40  74
    20  03  1F  F5  04  FF  50  B9
    20  03  1F  F5  04  FF  60  F3
    20  02  1F  F5  04  FF  70  78
    20  02  1F  F6  04  FF  80  BD
    20  02  1F  F7  04  FF  90  ED
    20  02  1F  F8  04  FF  A0  CF
    20  02  1F  F9  04  FF  B0  9F
    20  02  1F  FB  04  FF  C0  E1
    20  02  1F  FC  04  FF  D0  D8
    20  02  1F  FD  04  FF  E0  0F
    20  02  1F  FE  04  FF  F0  78
    20  02  1F  FF  04  FF  00  9A
    20  02  1F  FF  04  FF  10  57
    20  02  20  00  04  FF  20  E8
    20  02  20  00  04  FF  30  25
    20  02  20  00  04  FF  40  7C
    20  02  20  00  04  FF  50  B1
    20  02  20  00  04  FF  60  FB
    20  02  20  00  04  FF  70  36
1
  • 1
    Ok, lets start from scratch! How did you capture this dump? Did you use the cantools sniffer for that?
    – perror
    Jun 28 '18 at 15:09
3

As can be demonstrated by this page:

  • CRC width: CRC-8
  • CRC parametrization: Predefined, CRC8_SAE_J1850 (Polynomial: 0x1d, Initial value: 0xff, Final xor: 0xff)
  • CRC Input Data: Bytes, D1-D7

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.