On Thu, 13 Feb 2003, Russell McMahon wrote:

<snip>

> You really want 12 bits.

<snip>

> You could consider using an OTS Sigma delta converter rated at 12 to 16
> bits. Theseare usually cheap for what they do but relatively slow. You could
> also try Scott Datallos PIC code based Sigma Delta converter. Don't know if
> it will achieve the number of bits that you need here or not (it might - see
> Scott's information on PICLIst site). (search for Delta Sigma or Sigma
> Delta)

http://www.dattalo.com/technical/software/pic/a2d.asm

The "2-pin" version does have 12-bits of dynamic range. But 1) it's slow
2) the experiment was performed under controlled conditions. I'd like to
re-try this code with the F628's internal comparators. It'd still be slow,
but at least the comparator threshold is more stable than an I/O pin.

Scott

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