I pull up the MCLR line with a 10K resistor and don't use any diode.
My answer to picky circuits that take too much power was to make my
programmer with a big huge beefy supply. That way it can properly
drive the entire circuit while programming. In cases where you've
got stuff on the PORTB programming pins (I have an interface bus)
a big old printer A/B switch is a cheap solution. I just run my I/O
lines through there, and I can disconnect the bus when I program.

Andrew

On Thu, Apr 15, 2004 at 09:36:30AM -0400, Eisermann, Phil [Ridg/CO] wrote:
> pic microcontroller discussion list wrote:
> > I added a 100nf bypass and it does seem to work perfectly now.
> > Should I still bother with the MCLR diode?  I've never used one in
> > the past, but if its supposed to be there...
>
> For ICSP, something needs to both hold MCLR high and isolate it
> from Vdd. So you need at least a resistor from Vdd to MCLR.
> some datasheets tell you to use a resistor plus diode. A
> resistor alone may be enough depending on the rest of the circuit,
> and how beefy the programmer's Vdd drive is.
>
> Since you seem to be just starting out, go the safe route and
> use both a resistor and diode. Experiment later after everything
> else is working properly. But that's just my opinion....
>
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