> Does it make sense to build an ADC using a PWM output, low pass filtered
and
> a comparator from a 16f627 ?
> My idea is to conect the voltage i want to measure to one input of the
> comparator and the pic's PWM output to the other input. Then i sweep the
> duty cycle from 0 to the point  at wich the comparator changes. My guess
is
> that it's not a very fast ADC, but that's not a concern. Is this a
workable
> solution or are there any gotchas i should be aware of  ?

Nice idea, instead of sweeping though, think about doing a binary search by
starting at
50% and playing the higher or lower game, then to 25% or 75% etc.. would
increase
the speed- even though you say its not a concern now, you may want to use
this design in
a more time critical application later.

Jon Baker
( who used vitrually the same technique to build an analog joystick
interface not-so-long ago)

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