SERVICE NO. 1227277 1.8L AUT TBI 16059788 BZY

[Ludis Langens]

Peter Gargano wrote:
> 
> I looked at your '7748 info. again and realised that this ECM
> must be very similar to the '7165/'7808 etc. series ECMs.

Yup, same chip set.  GM has had several part numbers for most of the
chips.  I think they are just software compatible revisions.  The only
unique chip in the '7165/etc. is the 44188.  It is _not_ the same as the
14 pin DIP in a lot of other ECMs.

> Where did you get the pin designations for, say, U14 on the P4
> schematic? This is presumably the Motorola's 68HC11 variant.
> It has the right package for a HC11 but the pinouts are not right
> for, say, the 68HC11A0. Has anyone documented/investigated this
> and published their results?

Some of the pin functions are obvious once the circuit is traced out. 
For some of the I/O pins, I wrote a program that wiggled just one bit -
and then went and found which pin was wiggling.  Currently, the only
pins I'm not 100% certain about are pins 13 & 14, and the port 4 pins. 
Port 4 (@ $4004) appears to be three output only bits, but the other 5
bits in the control register might affect how they operate.  BTW, port 2
is a plain bidirectional port with a data direction register.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/