Russell McMahon wrote:
>
> Has anyone implemented a Sigma Delta converter in software, whether
> with a PIC or otherwise.
> I haven't but I am probably about to.
>
> For those who haven't met them, in their simplest form a sigma-delta
> converter is an integrator followed by a comparator (effectively a 1
> bit A2D) which tracks the signal. The mean output (digital) signal is
> the input signal. This can be measured by averaging o=r by using a
> digital filter. Essentially any desired sensible level of accuracy
> can be achieved given enough conversion time.

Walter has a full explanation and pictures too :
http://www.bytecraft.com/addaconv.html

If you pick Ri, Rf, and the sample times wisely, you
have zero maths to do, and the code becomes :
PinA := !PinB

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