This project is a very simple sketch that dumps information from selected CAN bus messages to internal Arduino EEPROM memory
Here it listens for Audi cylinder retards values stored in messages
7E8 05 62 20 cyl ret1 ret2
where
cyl 0x0A - cylinder 1 0x0B - cylinder 2 0x0C - cylinder 3 0x0D - cylinder 4
ret1 ret2 - negative hex number. To get angle in degrees, divide value by 100
Memory map 0-1000 - last 500 retards different from 0 1023-1024 - pointer to current saved value
Inspect EEPROM to get last dumps