Corvette CCM Reverse Engineering Anyone?

[steveo]

i'm working on a routine for optimized writes to the onboard 68hc11 eeprom over aldl, without any persistent programs in ram.

the logic kind of goes like this:

- read contents eeprom

- compare each byte at a bit level and determine required operation per-byte (ignore/program and erase/erase only/program only)

examples:
bin has 0xFF, eeprom has 0xEF: erase only.
bin has 0xEF, eeprom has 0xFF, program only
bin has 0xEF and eeprom has 0xEF, ignore.

- generate 'instruction list' and pack instructions in optimized fashion into maximum aldl packet size.

- send instructions

- read back altered areas and verify (or maybe i will just do a checksum run)

does this seem like a waste of time for the CCM? sure is......

but this entire thing should be able to be used to work with the internal eeprom on an ecm like EE so we can store tables both in e-side and t-side unused eeprom, which could be written very quickly with zero risk, so if someone wanted to relocate some critical table for rapid re-tuning, we'd be good with that.

if it works out, i will rework the EE flash tool so it simply compares/writes/whatever the onboard eeprom(s) right from the bin along with the main program, this should work seamlessly with the bin compare tool (you know, the one that figures out if we even need to write the t-side and e-side..), so if someone wanted to modify the onboard eeprom area in their bin, it would just reprogram that.