interfacing... Rotary Encoders

Dan Gendreau gendreau at
Thu Nov 4 21:42:44 CET 1999

> > There are a couple of algorithms read this signal. The more
> > resolution you want, the more complex the algorithm....

> I've seen descriptions of the hardware but next to nothing of
> software implementation.  Until you posted.
> Thank you for sharing this info.
> MC

Thanks, You're welcome. I figured it out mostly from scratch.

Keep in mind that for the software implimentation, its best to use an MCU
which can fire an interrupt whenever there is a transition on P1 or P2. Many
MCUs can be configured to do this for 1 or more pins of an input port.
Polling is more prone to false decodes during fast rotation.

-Dan Gendreau

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