Old 486 Board for ECU? Why?

[Diehl, Jeffrey]

Yes, the PC form factor is bad.  However, it can be improved.  I can get a
Baby AT motherboard which is about the size of my present ECU chassis.
Instead of an ISA card, how about an ISA ribbon cable connected to another
motherboard-sized card mounted in pancake fashion.  Power conditioning could
(probably) be done with a few regulators and some discrete components.  If
not, put it all in the engine compartment.

Then you get a case for this beast at your local RadioShack, say 3x8x8.  I'm
nost sure of the size off hand, but mount it on rubber feet.

My main interest in this subject is because I understand the hardware and
software involved.  I also see so much more that can be done with a general
computer as opposed to a tailored computer.  However, I'm just a newbie and
have much to learn.  I'll keep listening. ;^)

Mike Diehl,
MR-2, '87na

-----Original Message-----
From: Jim Tyler [mailto:toplessdatsun at ga.prestige.net]
Sent: May 01, 2000 2:24 PM
To: DIY_EFI-Digest at lists.diy-efi.org
Subject: Re: Old 486 Board for ECU? Why?


   


This topic sure seems to be using alot of bandwidth!

I have used PC motherboards on several embedded controller projects.
I don't think there is really a speed issue if you code in assembly or 
c/assembly and yes the development tools are great buuuuut,

on a practical note, think about what you would have when you were
finished:

1) A pc old motherboard 
2) an ISA card for IO, ADC's, current drivers, etc
3) another card ( or maybe physically part of the ISA) to 
do power conditioning, watchdog, etc., to try to get the PC to be
happy in the auto electric environment (i.e not reset every time junior
flips the power door locks)

Now you put it in a case the size of a small briefcase and try to ruggedize
it.
(you could go the industrial route but the costs gets out of hand quick)

The motherboard just wasn't designed as an engine controller.  (It would
make 
a good teller machine controller however)

A suggestion:

Why not take all that great JAVA pc development stuff and write a general 
purpose programmer for the most common and powerful GM ecm.  Sort of like
the SY/Ty editor but for something more common than the 749 ecm.

You could even start with a basic ground up general purpose ecm application,
specify number of cylinders, dis or hei ignition,turbo or non, map or maf 
etc.  Something pretty generic.

I realize someone would have to know HC11 code well to do this, but it would
be super useful to be able to go to any junkyard or parts place and get a
ecm (a 165 for example) and program it for whatever application you like.

At the end, we would have code of our own design on a ecm unit designed to
be
a ecm, not a rigged up pc.

Jim
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