Hi All,

I'm trying to get my arms around a problem that is probably simple but I
can't seem to come up with the best answer for.  I'm trying to use a 16F627
as an RPM encoder simulator.  The encoder I want to simulate sends 60 pulses
per shaft revolution.  I would like to simulate RPMs in the 10 to 500 range.
I would like to use 2 buttons to increment or decrement the simulated RPM by
1.  My math shows that the period of the pulse at 500 RPM is 0.00003333
seconds.  499 RPM is 0.0003340.  A spread of only .00000007.  The smallest
timer interrupt period is 0.00000040 seconds assuming a 10 Mhz clock.
Obviously not enough let alone time time to process anything in the ISR.  Am
I missing something?  Seems like this should be a cake walk for the PIC.

Assuming the first problem can be solved, would a lookup table be the
easiest way to handle feeding values to whatever method I use to vary the
pulse times or is there a simpler way?

Open to any and all ideas.

Thanks in advance,
Lance

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