gnupic: Pic A/d Weirdness.
Subject:
Re: Pic A/d Weirdness.
From:
Rogier Wolff ####@####.####
Date:
11 Nov 2002 11:22:38 -0000
Message-Id: <20021111121754.A16884@bitwizard.nl>
On Sat, Nov 09, 2002 at 07:13:01PM -0800, Scott Dattalo wrote:
> On Sat, 9 Nov 2002, Declan Moriarty wrote:
>
> > I have a little pic project goine here - e v e n t u a l l y!
> >
> > The one fly in the ointment is a temprature routine, in which my A/D doesn't
> > make sense, but returns a value of 3ff for the 10 bits :-(
>
> Try replacing the temperature transducer with a voltage source that can be
> varied. The best "voltage source" in your case may be a potentiometer. If
> you connect the two ends of the pot to Vref- and Vref+ and connect the
> wiper to your analog input, then you should be able to turn the knob on
> the pot and cover the full analog range. I'm not suggesting that this will
> fix your problem, but it can remove one of the unknowns.
Another thing I've done in the past is to measure the voltage on the
analog input to hand-calculate the expected AD conversion value.
Especially once it starts falling in range it is a good sanity check.
Roger.
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