How does the ais1120sx work?

[unternehmen]

About which bits is the CRC for AIS1120sx formed? 8 to 31?

[Eleon BORLINI]

Hi @unternehmen​ , AIS1120sx CRC is derived by the value of 32 bits (0 to 31) and results in a 8-bit value that evaluates the transmitted/received data are OK. The 32 CRC-related bits are described at p. 48 and 49 of the datasheet . Basically, the input of the CRC procedure is the 32-bit value previously described, that is divided by the polynomial function described in the datasheet p.48 and, if no error, the output of this division will be an 8-bit value equals to 00h. Regards

[unternehmen]

Hi Eleon,

that means I have to make a cyclic redundancy check over bit 0 to 7? What does it make sense if I form a crc over eight zeros? Can I not start immediately from bit 8?

[Eleon BORLINI]

Hi @unternehmen​ , this is the required standard for automotive grade. 32 bits are required to check a series of registers, but the final check can be done on 8-bit. Regards