Tony's code is very clever, and just shows what can be achieved via software alone.  However, as he himself has stated, it was only designed for relatively slow reving engines.  The trouble with the software only approach is that you have to complete all calculations and keep a pretty accurate counter in between firing cycles.  The Motorola uP such as the 68HC332 have a TPU (Time Processing Unit) which is extremely powerfull.  It can actually run an engine in steady state with no CPU intervention, leaving the CPU bags of time to perfrom some very intensive maths.

I think a good compromise could be met using a PIC with the Capture/Compare units, which would at least offload a good deal of processor time.  I have been thinking about a PIC based system on and off for ages, but never seem to quite have the time to sit down and work through it.  Maybe this is a good time to put our heads together?

Your application of traction control might actually be slightly more simple.  I presume you need to reduce power once the wheelspin has started.  You only need to retard the igniton from the mechanical configured settiing to reduce power.  You might even get away with introducing fixed delays that are not proportional to engine speed, which accumulate the longer wheel spin progresses?

Regards

Mike

-----Original Message-----
From:   John Pearson [SMTP:xero@CMC.NET]
Sent:   Tuesday, May 02, 2000 4:15 PM
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Ignition timing, 2nd iteration....

Thanks everyone for all the responces and offers for help.

I think I will try to tone this down a little. Make it a bit easier.

How about taking the signal from the dist. with mechanical and/or vacume
advance working, and proccessing that signal by adding delays. Safer and
less complicated.

What I am trying to do is smooth out the power from my motor. The car is a
drag car with front engine, rear wheel drive. At well over 1hp and 1ft/lb
torque per 10lbs weight, and street radial tires, accelerating from a dead
stop is very difficult. I read that pro street stock racers use timing
computers to help with traction, and guard their curves with their life.
These computers are not cheap. I think they start at $700.00.

So, perhaps using the original curve from the dist, and tailoring that
before it goes to the ignition module would be a good compromise.

John