I'm delving deeper into my 1227302 ecm. The schematics off the ludis site generally give only Delco part numbers for the ecm ICs. I'm interested in more info on the ROM part. This is the part the ludis site identifies as a RAM/ROM/IO part. There are two of them shown in the schematic and the Delco part numbers are,

16050535
16050537

Are there real motorola or other manufacturer part numbers for these parts? I remember back in the day very similar peripherals for the 860x family. I can find the 8246 which had 2K ROM, 8 IOs and some timer functions but no RAM. Maybe the ecm part is similar to this?

Assuming someone wanted to burn new ROMs you would need to get blank parts or (if these are masked) otp or otherwise programable parts.

If all else failed, if there was enough info on the parts, a substitue module could be built that replaces the Delco ROM.

Thanks,

Frank

 

AFIK these parts have no open source equivalent. Best bet is to disable the ROM portion and move the ROM code into EPROM. Also known as ROMLess(tm).

Look for the ROMEN and ground it. Most of the time it has a pullup which allows that signal to be grounded. Once grounded the on-board ROMs are disabled. Now need to move the ROM code to EPROM and do whatever you want.

RBob.

 

RBob,

Yes, that's a good plan and a varient on one of the possibilities I'd considered.

If I were to go ROMLess would the ROM code go in the calibration EPROM? Use something bigger and wire the ROM decode to the additional EPROM space?

I assume that if you disable the PROM the I?O and RAM still works in the RAM/ROM/IO chip?

Can you direct ma to a thred or link on going ROMLess?

Frank

 

This thread has some good info:

https://www.thirdgen.org/techbb2/sho...hlight=ROMLess


Yes, all of the ROM code goes into the EPROM. Generally I use a 128kb EPROM in place fo the 32kb {edit: was 4kb} device. With the disabled ROM the rest of the chip functions are still active. All of the C3 TBI ECMs I use are set up this way.

IIRC the '7302 is an early MAF ECM? The '165 may be an easier upgrade.

RBob.

 

Yeah, that's perfect. Thanks for the pointer.

I had read the thread on 302 to 165 some time ago. It looked daunting. However, I just went back an reread it and now it doesn't look too bad. I think before I was just starting out coming up to speed on the ecm and also I think all the 749 stuff mixed in confused me a bit too.

I'm going to have to reread a few more times and think it over.

Frank