Ah... that explains it then.

It might well be dragging up/down the PGC and PGD pins but I don't need
them yet so haven't checked.

Now I know, I will make provision at the programmer end to isolate the
cable when the programming cycle is complete. That will be no hassle.

New USB programmer? I couldn't see that on your site.

When will that be available?

Thanks for all your help with this.
Joe.


-----Original Message-----
From: Olin Lathrop [mailto:olin_piclist@embedinc.com] 
Sent: 10 January 2006 19:31
To: Joe Farr
Subject: Re: [PIC]: Embedinc's EasyProg and 18F4550

Joe Farr wrote:
> However, to get the circuit to run, I have to disconnect the link from
> the PIC's MCLR pin to the programmer cable (I can leave all the other
> signals connected). It looks like the programmer is dragging this
signal
> to GND.

Yes it does.  The EasyProg was originally designed as a in-socket
programmer
and does not have the capability of releasing the lines to let the
target
run.  The ProProg and the new USB programmer are designed for ICSP and
do
have this capability, but I know that's not much help in your case.

All I can suggest is to put a switch in the Vpp line.  I'm actually
surprised that the EasyProg isn't also interfering with PGC and PGD.


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