repair an 8051 PCM

[steveo]

ok, I was finally able to get my pcm working again. Not sure if positional or the chip but the last iteration flashed both sides without a single error so I'm going to leave it alone as long as I can.

i feel your pain. i think my socketed ECM behaved best with two folded business card chunks under the chip. it's some real voodoo getting that thing right.

honestly i think someone just needs to bust out an ohmmeter and trace the address lines back to the ECM's processor. we have data sheets for the processor pins and eeprom laying around. descrambling it iteratively proved really annoying but i could try that way again too...

[space387]

i feel your pain. i think my socketed ECM behaved best with two folded business card chunks under the chip. it's some real voodoo getting that thing right.

honestly i think someone just needs to bust out an ohmmeter and trace the address lines back to the ECM's processor. we have data sheets for the processor pins and eeprom laying around. descrambling it iteratively proved really annoying but i could try that way again too...

I'm off this weekend, I'll see if I can get a record of the order each address is accessed during a write and we can match it to the order transmitted to the ecm.

[steveo]

that’d be cool. i have a new ecm in the mail so if that fails i’ll do a hard trace of the address lines to the ecm and see whats going on there. the possible permutations for arranging 16 address lines is totally insane. it’s basically encrypted.