Take a look at http://www.bytecraft.com/addaconv.html
for a very simple A/D.

If you need more bits, just add some dither to the analog signal and then
use the average value of many samples.

For example, the average of 4 samples will add 1 bit of resolution to the
measurement. The average of 16 samples will give you 2 bits .

-Frank



----- Original Message -----
From: "juan manuel garofalo" <animacion3d@HOTPOP.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, February 04, 2002 6:08 PM
Subject: [pic]: adc


> Hi there:
>
>
> 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  ?
>
>
> Thanks in advance.
>
> jm
>
> --
> http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
>
>

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body