GM ALDL interface

[nospan at anywhere.usa]

Frederic Breitwieser wrote:
> 
> >Does this program take the place of messing with constructing the ALDL-PC
> >interface that has bounced around from Peter I believe for a while along
> >with the Fiero basic code and all that?  Does it work for both 160 and 8xxx
> 
> Actually, it does work pretty well.  I think its similar to the infamous
> "turbo link" product that the GN folk buy, desire, etc.  Of course this
> program just takes and dumps the data, nothing fancy, so I'm not comparing
> the two things...
> 
> But it is an excellent framework to build your own ALDL downlink...
> 
> I created a single-transister circuit to make the proper voltage
> adjustments (12v to 5v), however over the next day or to I'll have an
> opto-isolator circuit that's even better.  Okay, four parts instead of
> three, with a wild ballpark in cost of about $8.
> 
> >baud ECMs?  Also, what do you mean by you "slowed down" the program?
> 
> It just works with the 160 PWM ALDL stuff that GM pumped out in the 80;s.
> The 8192 serial data can be read with your PC serial port either directly,
> or with a simple UART circuit to do the serial conversion.  Timing requires
> effort, but its not a big deal I don't think, though I have a 160 bps PWM
> ECM, so I'm focusing on that.
> 
> As far as slowing down the program, or speeding it up, the timing loop is
> based on "for x=1 to delay / next x" type of software delays to capture
> data at the right speed.  The only issue with this the delay loops before
> the next byte fetch will vary depending of you have a 286 running DOS only,
> or a Pentium 166 running NT with all the multi-media crap installed.  What
> I'd ideally like to do is take the efforts Sean started, and work with him
> making a windows based ALDL reader software for Win31, 95 and NT, so its
> more universal as far as PC requirements.  Interrupt based of course.  Just
> that its been ages since I've written a line of code!
> 
> Anyway, the basic program that Sean has on his website does work, and I got
> a lot of codes out of my 1986 LeSabre ECM that's sitting on the garage
> floor.  Lots of codes.  It failed almost all the sensors, but I didn't have
> the engine attached to the harness at the time :)
> 

I haven't tried yet to run the program on Sean's page because I am still
sorting 
out the wiring harness in my basement, but does this program only dump
out the
error codes that are run during a normal self test?  Can't these be
received
by simply shorting the A and B terminals on the ALDL and then just
watching
the 'Check Engine' Light?

I was thinking that there must be someway to receive the data that the
engine
is processing - i.e. what the TPS voltage is, O2, etc etc. Just like a
Diacom.
Or is this what the program does and because it wasn't connected to
anything
it just did not have anything to report.

Also, I believe you said you added a line of code, Frederick.  What did
you 
need to add to the program?

I will volunteer to help with this Win '95 code project.  I must admit
that
I probably will not be able to help with the serial/parallel interface
coding as I have very little knowledge of writing such interface code,
but
I will gladly set up a user interface for Win '95 / NT.  I have Visual
C++
and wrote a wheelchair program for my Master's thesis so the user
interface
shouldn't be a problem (especially since it seems like there really is 
nothing for the user to do other than run the program and watch the
values
on the screen).  Any volunteers for the more difficult part of the
program?

Finally, I was wondering if anybody might know or might know where I can
find out, what the coding is on the PROMs used in '85.  I found out
that one of my friends at work has a PROM programmer and he has no
problem with me using it to burn chips for my car.  If somebody could
help me with the code I would really appreciate it.

Thanks again gang!

-Chris Bruno