Corvette CCM Reverse Engineering Anyone?

[spfautsch]

While mode 5 is active 02 requests stop working, and mode 5 seems to timeout after about 1 second. Mode 6 requests inside that timeframe (and outside it) give no reply.

Let me correct this one. It appears that mode 5 will stay active without keeping the bus active.

What I've found is that if I upload a routine that doesn't end with an RTS instruction, the processor resets. Also sending anything other than 05 and 06 commands while in mode 5 resets the processor as kur4o noted.

I'm pretty sure what I'm sending is working, but have no way to know other than the fact that mode 5 stays active as long as I don't send anything other than 05 or 06. I know this because the reman pin only needs to be shorted momentarily and responses to 05 remain AA until it resets whether the pin is shorted or not. I'd try turning on an output like the courtesy lamp pin, but I think the processor has to send commands over spi to handle this and that's way outside of my machine language skillset.

I'm tempted to try my hand at disassembly, but thus far that's never ended well. Otherwise I'm at your mercy guys - any ideas on the entry point for the eeprom routine?