At 11:39 PM 7/17/97 -0400, you wrote:
>I am using a '509 to read a pot and output a PWM on one of the ports for LED
>dimming.  I charge a cap then measure the discharge time through the pot for
>the A/D conversion.  It works, but my code is clunky and too slow to do the
>PWM at a high enough frequency.  Someone out there must have already done
>this.  Any code or advice would be appreciated.
>
Brian,

Some off the wall suggestions ....

a. use your pot in a _high_ frequency oscillator and measure the change in
frequency

b. cap charging to 63% of supply rail is very linear (1/RC). So use a
comparator set for 1/2 of 63% and time comparator switch point and double.

c. (tongue in cheek) throw away the pic and use a 555 and pot to vary your
led's brightness.

Regards,

Ross McKenzie
Melbourne Australia