it's ok for small capacitors, ie: 100nF to a few uF.
even with external supply connected the icsp will work.

On Wed, 23 Jan 2002, Tim Webb wrote:

> Is it ok to have capacitance between Vcc & GND during ICSP?
>
> Or will this cause problems too?
>
> Tim
>
> -----Original Message-----
> From: x [mailto:bagameri@FREESTART.HU]
> Sent: Wednesday, January 23, 2002 5:41 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: In-Circuit programming for 16F877
>
>
> Have a look at "PICMicro MID-Range Reference Manual".
> It's on Microchip's site, in  .pdf form. You will find a whole section
> about ICSP in there. Section 28 is that.
>
> My experience is that Picstart Plus and ICSP works fine, but:
>
> - don't apply capacitance to any PIC pins when programming.
> - ensure that LVP is disabled and LVP pin is pulled down when
> programming
> - my ICSP cable has 5 conductors and 6 pins at the PIC's end. The 6th
> pin pulls down OSC1 to GND. In Your case, this 6th pin can disable the
> oscillator.
> - employ a 5W2 header. There's the PIC on one end, here you can plug the
> programming cable. when the PIC runs, put on 5 jumpers, because the
> environment is connected to the other end of the header.
>
> Sincerely:
>
> Bela
>
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