Update on 93 Z28 disassembly

[Roger Heflin]

On Mon, 14 Dec 1998, steve ravet wrote:

> > Here is a question:  I have identified that two of the modes output
> > data streams similar to the 0x01 mode (different data, and fewer
> > bytes), diacom does not read these data streams at all.  One of the
> > data streams has 15 bytes, and the other I believe has 3 bytes.  I
> > know from the service manual that there should be info on the ABS
> > subsystem and maybe other subsystems available.   Does anyone know
> > if all the extra data streams go the same ALDL connector?
> 
> Excellent work, Roger.  Are you just watching what happens between
> Diacom and the ECM do determine all this?
> 
> Communication from other computers (ABS etc) does come to the same ALDL
> connector, but to different pins in it.  At least for a '91 Caprice
> 16156965, which is the service manual I've looked at.
> 
> --steve
> 
Flowcharting, and reverse engineering the prom code.  I have found
flowcharts are very very helpful.   So far I am doing all of this work
without actually tracing out (or actual physical testing) of the
computer.  It is all from carefully determining what the code is
doing.   And having the list of the ALDL data stream goes a long ways
to getting a pretty good start.


The different pins tells me that it may not be in this computer except
that this computer seems to have two serial interfaces, and the other
once sounds like a higher speed computer to computer interface for
talking to another computer.

				Roger