On 17 Jan 2014, at 19:01, Sergey Dryga wrote: > 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, the= n > increment count, if R is low - decrement. =20 If I understand your suggestion correctly then surely that halves the resol= ution of my counter? It only adjusts the counter when channel A changes sta= te, whereas the dual interrupt solution gets a count every state change. Of course, if your code is less cycles then i could use an encoder with dou= ble the output rate. > 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 I don=92t believe that I need debouncing with the encoder i=92m using thanks for your help! --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .