ok... second post

John S Gwynne jsg
Thu May 5 03:41:53 GMT 1994

It's feeling a little used know... :)

Let me introduce myself too. I'm a electrical engineering grad student.  I
graduated back in '86 with a BS... work for a while in the defense industry
as a CPU hardware guy (I used 6809's and 68HC11's as controllers for airborne
synthetic aperture radar systems).... and then returned to grad school. For a
little over six years now I've been studying how to make low observable
(stealth) aircraft. Well, now that I'm about to graduate that market is 
gone :(. Such is life.

Anyways, my latest passion (rather resurgence) is playing with engines. Come
to think of it, most of my toys all have engines (RC planes/boats/cars, dirt
bike, Jeep,...). I liked what I read in Brian's post. If we can get a hand
full of people together that can each contribute to a portion of an EFI
project, I have no doubt that we can realize some of these dreams.

That's a good lead into what I believe should be the first order of
business. I personally believe, especially at this level of prototyping, that
our first step should be to standardize on a bus configuration that each of
us could adapt to. For instance, I have a small circuit to measure RPM that
simply plugs into the tach port of my MSD unit.  It's just a simple state
machine based in a GAL chip that controls a 82C54 (10MHZ programmable timer)
with a high speed comparator/conditioner (ok, looks like 14 components for
conditioning and surge protection). Its use is simple and does not require
CPU intervention.  For everyone interested in taking advantage of this
circuit and knowing that we will never get everyone to agree upon the same CPU,
it would be to our advantage if we could agreed upon a common bus structure
that would be compatible with each of these small sensor interface circuits.
That also gives us the flexibility to change circuits easily for upgrades and
enhancements. I'm thinking something *vary* simple that could be adapted to
by everything from a parallel port of a laptop to a single board 68HC11. In
other words a common point that we can work from since I feel its ridiculous
to expect the entire design at once. This also gives us the ability to start
small with simple "engine instrumentation" that will then expand into the
final "engine management" system.

I would like to hear comments for everyone on this as this is something that
must be decided up-front. It will be much more difficult to work together if
we all use the CPU bus directly (i.e., asynchronous 68000 type CPU bus vs the
synchronous 68HC11 vs the parallel port on a lap top). IMHO, we need a common
point between all of these approaches.

                                       John S Gwynne
                                          Gwynne.1 at osu.edu
               T h e   O h i o - S t a t e   U n i v e r s i t y
    ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA
                Telephone: (614) 292-7981 * Fax: (614) 292-7292

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