JeremyW wrote:weber wrote:In case anyone still cares about the 8-bit CRC in the Leaf's ID 0x1D4 CAN packets, my colleague Coulomb and I have reverse-engineered it. We used the excellent method described in New Zealander Greg Ewing's awesome paper, "Reverse-Engineering a CRC Algorithm".
The polynomial is 0x85 using left shifts. It takes the bytes in little-endian order and the initial value and final XOR are both zero. The only place that I can find that this polynomial has been used before is in a Nintendo game controller.
We'd be very interested to know if anyone has any evidence that this actually contains a torque command from VCM to TMI. It looks to us like telemetry going the other way. We'd also be interested if anyone has any theories about what ID packet does contain the torque command.
Thank you so much for this. Seriously. I'm going to use it to "tune" my leaf. Oh yes.
Sweet! Nice job!