GM ALDL interface

[Terryk]

The only thing my C code has different is that it is processor speed
independent. But that could be added to the Basic code easily.

TK

----------
> From: Frederic Breitwieser <frederic.breitwieser at mcione.com>
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: Re: GM ALDL interface
> Date: Tuesday, December 09, 1997 1:54 PM
> 
> >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 just went out yesterday and bought all the parts to build the
interface
> too!
> 
> I did as well, they've been sitting in the box with the packing slip in
my
> garage, complete with the Maxim chip.  While there is nothing wrong with
a
> complex circuit that converts to a serial port, this solution is just
more
> software based.  There's merit for both actually.
> 
> I prefer the software method only because I can shove the teeny-tiny
> interface into the cable end rather than having a box hanging off the
> notebook.  Who knows, maybe I'll start a business making opto-isolated
ALDL
> cables.  NOT!!!
> 
> 
> Frederic Breitwieser
> Homebrew Automotive Mailing List
> Bridgeport, CT 06606
> http://www.geocities.com/MotorCity/Downs/4605/index.html
> (Portable Webserver Link Address)
> 
> 1989 AG Hummer 4-Door
> 1993 Supercharged Lincoln Continental
> 2000 Mid-Engine Sports Car <smile>
> 
> ---