pic microcontroller discussion list wrote:
>> http://www.voti.nl/blink shows ICSP circuits for
>> most flash PICs. No, an
>> xtal is not needed.
>
> Sweet, that's almost exactly how I have my circuit
> with the exception of that 1n4004 diode.  What is it
> for?  I notice it's not in the breadboard picture?
>
> http://www.voti.nl/blink/index_1.html#16F871
>

your original message mentioned PGC and PGD being
connected, but nothing is said about /MCLR and PGM.

I assume you have /MCLR connected to the programmer
and isolated from Vdd. IIRC, on the '877 you should
ground PGM (low-voltage programming) if you are not
using it. Wouter's diagram shows PGM connected to his
programmer.

i just checked www.piclist.com and there is a portion
of that page:

<quoted>
When these parts a blank (like when new) or any other time the when the LVP
config bit is programmed as a '1' the state of RB3 becomes an issue. It must
NOT be tied high as VDD rises or unpredictable results occur. I could not
get any satisfaction trying to read or program a part in this condition.
Exactly why I cannot say. It appears that the chips cannot enter either the
low or high voltage programming state. This condition is not documented in
the programming specs so we are left to wonder.

If RB3 is low there is no problem.
<end quote>

there's more, but it relates to the 16F87x parts.


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