Spehro Pefhany wrote:
>
> At 10:19 AM 6/29/01 -0600, Roy Souther wrote:
> >I added an external pullup resistor to it but it did not help.
> >
> >Looking at it on the scope in does a saw tooth wave that peaks at about 1V
> >then a sharp drop.
>
> What kind of freqency response to you have on your scope? Is there an
> optional low pass filter you can switch out? This should work, but the
> times "on" and "off" will probably not be equal, and if you are running
> at 20MHz, the times on/off will only be a microsecond or two.


Getting 20MHz at RA4 is a bit of a feat, and with
most frequencies less than than you would expect more
of a square wave I bet.

Supplying more info re the freq and what he is driving
with the PIC pin will help quite a bit. The "sawtooth"
comment seems to imply that the load is too much for
the PIC pin, maybe just reducing the ohms value of the
pullup resistor might do it, or examination of the
capacitance of the load vs the freq etc.
-Roman

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