Incremental rotary encoder with 128 PPR? For MIDI CC

[ShermanP]

@MarkT

True, but its a mechanical switch turned by a human, there is negligible overhead even if it bounces a dozen times per transistion. If that worries you can poll regularly to limit the overhead.

I agree that it may not matter if there are lots of interrupts per transition. I just wanted a way to reduce the interrupts in case it does matter in a particular situation. And I would say that polling hardly reduces overhead. If the encoder is idle, the polling still cranks along.

@MarkT

Hysteresis means having a dead-band, for instance of 1 count - so that oscillating a count back and forth is hidden from the user. One way to code that is record the last two distinct count values (which will differ by 1), and only updating when the actual count becomes larger or smaller than both the last two reported positions - this will hide bounce.

With a standard encoder you would have to accumulate 4 transitions in one direction or the other before reporting an actual detent change. Or for the other type of encoder it would be +2 or -2. So one switch oscillating back and forth shouldn't cause a problem in the first place.

But if you had an encoder without detents, and were counting every transition of either switch as a reportable tick, you'd have to do something to prevent flutter, and your method would do that. The only downside is you would have that dead spot when you change direction, but that's not a major problem.