crankshaft/flywheel encoder patterns

[Mazda Ebrahimi]

> Have you thought of using the flywheel or flex plate teeth for the source of
> timing pulses?   This would give more resoultion if accurate pickup can be
> made.  I was thinking of using a single counter and decoders for each
> injector and spark plug.  The cam pulse resets the counter and each set of
> decoders would be loaded with the start and stop count.   This may take more
> hardware but allows for positioning and duration control.  Once loaded the
> system requires no CPU action under steady state conditions.  me

That's exactly what I'm going to do.  I basically use the crank sensor input for three 
purposes: 1-To increment my degree count, 2-To trigger my counters for injectors and 
coils, and 3- to calculate RPM based on period of the pulse.  I use the cam sensor to 
reset the degree count to zero.

I'm using separate counters for each device right now.  I didn't design the board 
myself, but I'm pretty sure there is a decoder that I write to, which inturn loads the 
proper counter.  The counters then count down based on the crank pulse.

Best Regards,
Mazda

Currently, I'm using a 180 tooth wheel fixed to the harmonic balancer.