slippyr4 <slippyr4 <at> gmail.com> writes:

>=20
> Hi all,
>=20
> I want to count pulses from a rotary encoder who's output is 2 channel gr=
ay
> code. I need to increment a counter when the encoder turns one way, and
> decrement it when it turns the other way.

You can use only 1 interrupt, and look at the state of the other pin.=20
Example: interrupt on L channel, then check R channel.  If R is high, then
increment count, if R is low - decrement.  You might need debouncing on L
channel (or inhibit subsequent interrupt for some time), but not on R
channel since the channels are 90 degrees out of phase, which provides
sufficient time for the contact to settle.=20

Also, some PICs have hardware quadrature decoders which might be beneficial
to use, depending on your application.

Sergey Dryga
http://beaglerobotics.com



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