Now what?

[Roger Heflin]

On Tue, 25 May 1999, Bruce Plecan wrote:

> 
> OK, for grins lets make believe I got something that says what the ALDL code
> looks like, ie the list of erroe codes first, how does that get me from
> where I am?, to reading code?.
> Grumpy
> 

Then you need to find the area of code that drives the ALDL port, and
decode it.  ANd it is really ugly code, because of how it needs to
work.   The way I found my code was I figured out the two possible
pieces of hardware that could could have been driving the ALDL port,
and deocded the code driving them (the interrupts for those pieces of
hardware).   To figure out the hardwware you would need to have enough
info to make an educated guess of which 68hc11 series variant is being
used for the vehicle in question.  Now if you knew where some of the
data in the ECM is, that is also outputted to the ALDL you might be
able to find the proper table listing the addresses to the ALDL port
without completely understanding the assembly code.   

			Roger