On 10/13/09, Robert Rolf <Robert.Rolf@ualberta.ca> wrote:
> William Couture wrote:
>
> > I know that you can use a ADC input and a series of resistors in place of
> > jumpers (if you are short on input pins).
> >
> > My questions are
> >    * how many "jumpers" can you reliable read with a 10-bit ADC?
>
> LOTS. Depends on the precision of your resistors and the contact
> resistance. 8 if you can get 0.1% precision Rs. (256 states)

  Depends by the noise on your board (AKA driving motors, relays,
triacs or other noisy stuff). I've seen situations when 8 bit AD (from
a 10 bit converter) can't be safetly used unless everything driven is
OFF.

Vasile
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