On Wed, Apr 14, 2004 at 10:57:48PM -0400, Ken Pergola wrote:
> Robert B. wrote:
>
> > The MCLR pin is just attached to the ICSP header, so I guess it
> > is floating.
> > I was under the impression that it needed about 13v on it to affect
> > anything, though... is this not true?
>
>
> Hi Robert,
>
> If the /MCLR  pin is indeed floating, that is a problem since the PIC will
> be resetting when you don't want it to. Ideally, when /MCLR is not asserted,
> you want it to be as close (in voltage) to the PICmicro's Vdd as possible.
> Read up on the data sheet about /MCLR and reset circuits.

I usually use a 1k pullup from MCLR to +5V. Don't use a capacitor in the
circuit because if you slow the rise time too much, it starts to get flaky.

Once you've done this then you can add a reset button simply by tying a
pushbutton switch between MCLR and ground.

BAJ

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu