Interrupts based quadrature encoder counter

[Demon]

I keep this comment in my code that uses encoders:

'  Wiper Chart:
'  ============
'     A   B
'    --- ---
'     0   0
'     1   0  /\ CCW
'     1   1
'     0   1  \/ CW
'     0   0

You can check position by reading the Port, and you can check rotation by checking previous position of the two wipers.


I suggest you keep a log of the two Port pins (send a HSEROUT to your PC if you don't have tools like the Saleae Logic probe), and see if your encoder sends the same pulses.

Note that "some" encoders send pulses between the clicks that you feel on the shaft, so don't trust your fingertips.