Dave Alger wrote:
>
> Hi all,
>
> Wonder if anyone can help.
>
> I designed a product using the PIC 16F84... we use a surface mount part and
> program it on the board. I had to introduce a jumper to allow me to isolate
> MCLR from the POR circuitry during programming and it worked fine.
>
> Recently we've had to switch to the F84A... for some reason that won't
> program on the board. I tried programming it on a bare board (just the PIC
> and connector pins) and it worked, but with other components it seemed to be
> useless.
>
> Strangely a guy here has found that by adding capacitance to the MCLR line
> during programming it can be made to work... but we're not sure why.
>
> Anyone got any ideas at all?


Yep, try a series resistor of about 1k on your
programmer wiring to MCLR. :o)
-Roman

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics