Hi,
time the period between edges in order to calculate the engine RPM
Why dont you count pulses over a fixed time period, then calculate the RPM.
As you RPM goes up, the period goes down, you need to process faster and faster between pulses.
If you count over say 1Second, calculate( x 60), display, then go back and count again.'
Have you used a signal generator as an RPM source to check your code algorithm with a clean square-wave signal?
Tom... 