SOLVED: How can I reduce ADC jitter

[Ioannis]

Lets clarify something Robert please.

Do you expect to have an ADC reading that will be absolutely stable on every pot position? Say that a user can set 1023 positions on the pot. Do you expect to have solid 1023 readings?

This cannot be done no matter what. On an absolutely perfect circuit you will get +/- 1 digit because of the way ADC works along with every kind of noise present (wire induced, ground loops, resistors noise, shot noise, Johnson noise and so many other kinds).

The ADC steps are 5/1023= 4.8876mV. This means that if ADC input is over that step, you get a count of 1. But if one of the above noise or more than one is present, you may get 0 or even 2 as a result, if the noise adds another 4.88mv.

Hope this is clear and helps you not chasing the impossible.

Any kind of averaging helps but because of the above, it does not eliminate the small jitter that you should accept.

Averaging with Moving average routine limits the maximum number of counts. The one Richard posted on #57 goes up to 1004 after about 30 samples. Darrels Taylor Oversampling routine does also suffer of this kind of problem. Well gives from 8bit ADC a 16bit result but you have to pay in time...

Best keep a simple average of 10 samples and get done with it.

Ioannis