Patrick J wrote:
>
> I am wondering, have anyone tested max speed for a polled program
> decoding an rotary encoder ? Would an interrupt driven program
> do better ?
>
> PIC16F877 @ 20 MHz. Approx 50 instuctions in the active loop
> Encoder is 100 pulses/rotation, quadrature decoding (400 flanks/rotation)
> I have reached around 2000-2500 rpm. 3000 rpm gives overspeed error.

A suggestion, why not get some black paint
and with a fine brush fill in every second
hole, giving you 5000 rpm straight away,
at small cost of losing a bit of positioning
accuracy? VCR repairers always have a little
jar of black paint near their bench. :o)
-Roman

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