thomashenauer/chargemaster-protocol

USB protocol for Chargemaster 2 compatible battery chargers

chargemaster-protocol's Issues

Transaction type decoding

Hey Thomas,
great work so far! Also having a SkyRc Charger I too thought about decoding that protocol.

Well, I think I've got news for you:
The byte before the End Sequence is the modulo 0x100 checksum of the data block, beginning at type, ending at length-1:
Example: 05-Transaction:

0000    0f  16  05  00  00  02  01  08  98  07  d0  0c  76  10  5e  00
0010    00  00  00  00  00  00  00  6f  ff  ff  00  00  00  00  00  00

(5 + 2 + 1 + 8 + 98 + 7 + d0 + c + 76 + 10 + 5e) mod 100 = 26f mod 100 = 6f (Tadaaa!)

I checked that for EVERY transaction you documented, so I think that's it.

Hope that helped!