I haven’t had much in the way of extra time, between work, spending my days off wiring a project car, and tending to the usual social agenda that leaves me little free time to advance my personal knowledge, so things have been a little slow lately. I don’t really mind any progress is progress, I have been most pleased in my understanding of the Subaru ECU I have been reverse engineering.. Actually it has been more like a lesson in assembler language which was a huge undertaking and months later am still at a basic understanding but it’s better than none!
One thing that I have also been working towards a better understanding of is how to use eproms in circuits. I hope to one day build a romulator but that is one item on a long list of cool gadgets. At the moment I made a DIP28 breakout board so I can test breadboard style proto-typed circuits, I have verified this on my running subaru engine using a basicstamp to listen to the rom socket for data / addresses. Works pretty slick!
The socket on top allows you to insert your original rom for eavesdropping:
Another advancement on the SVX ecu front, I ordered the adapter boards from http://www.alcyone.org.uk/ssm/index.html using the express pcb software and two electronically erasable 27f512 proms. I have since started creating my own maps but more importantly changing the ecu code! Removing the EGR code was a success but I have run into some issues with the rev limiter code and I am at a loss for what todo..
I have noticed there are two revisions of these ecus, one seems to have some type of debugging header on the front side, this ecu was out of an early 92, this was the ECU that came with an upgrade prom. Here are some snapshots:
Now compare that with the late 92 design revision:
This is something I definitely would like to investigate further into. I would expect to see an ECU project page here soon and this summer expect major advancements when it comes to using this information to reverse engineer the VW motoronic systems..