From: "Scott Dattalo"


> On Thu, 13 Feb 2003, Russell McMahon wrote:

> > 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.

I just did something like this using the 628.  I only wanted 8 bits of
resolution, and it worked quite well.  It is slow though.  :-(  Dave
Tweed is "pretty good" at this stuff.  ;-)

michael brown

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