Jonathan Hayes wrote:
>
> Anne Ogborn wrote:
>

> "Relatively fast" would be someone turning a shaft.  Actually, all I
> only need is
> about 120 degrees span and about a tenth of a degree resolution.  I've
> read about the
> poorly shaped outputs of these things and am wondering if I can update a
> display fast
> enough.
What optical encoder you use? Is it an industrial rotary encoder? Then I
can't understand what you've heard about poorly shaped outputs. They got
very good square wave outputs.
Let's do numbers:
For 120 degrees @ 1/10 step is 1200 steps. Times that by 3 means you
need a 3600 step encoder, those are available.
Let's say somebody turn a shaft 360 degrees in one second (To get 1/10
resolution, I think that is still quite fast).
1/3600 gives you 277 microsecs per step. So at 4 MHz you have 277 PIC
cycles to read the two pulses of one step. At 8 Mhz, you have 554 PIC
cycles, etc.

So I would say, yes, a PIC will do what you need.

Quentin