Let me try this again.

PGC and PGD are RB6 and RB7 respectively.  In your schematic you show the
PGC and PGD pins going to the OSC1 and OSC2 pins.
This is why there is no ICD functionality with your circuit.

If you connect the ICD pins to OSC1 and 2, you effectively disable the
oscillator.

Try moving the ICD PGC and PGD pins to RB6 and RB7.  You should be able to
use the ICD then.

Regards,

Jim

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
jana1972@centrum.cz
Sent: Saturday, November 05, 2011 9:45 AM
To: Microcontroller discussion list - Public.
Subject: Re: [PIC] IS this faulty?

Thanks ALL who replied.
I do use capacitors in the schematic.
Please see the schematic here
http://www.dilynamobily.cz/Media/Uploaded/Normal/Problem.jpg
( the link is case sensitive)

My problem is that I can not debug any program using PIC16f648A - ICD=20

Please check and let me  know if you can see any problem
Thanks
L.


> OK, whatever.
>=20
> We don't know for sure if there are any capacitors or not.
> And if not, isn't it a possible "problem" ?
> I think it is.
>=20
>=20
> jim wrote 2011-11-05 14:53:
> >
> > The main reason for the capacitors in a crystal circuit is to provide a=
n
> > intentional imbalance between the input of the oscillator and output pi=
n
of
> > the oscillator so that when power is applied, the imbalance causess
current
> > to flow, and thereby guarantees the oscillator will start oscillating.
> >
> > Jim
> >
> > -----Original Message-----
> > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behal=
f
Of
> > Isaac Marino Bavaresco
> > Sent: Saturday, November 05, 2011 7:45 AM
> > To: Microcontroller discussion list - Public.
> > Subject: Re: [PIC] IS this faulty?
> >
> > Em 5/11/2011 10:57, Jan-Erik Soderholm escreveu:
> >>>> I *think* that the header is useless without a target circuit.
> >>> But what is the smallest target circuit?I thought adding only crystal
is
> >>> OK for starting debugging
> >> Right, but a crystal is useless without capacitors. And it is
> >> a bit unclear how the header is powered.
> >
> >
> > Not exactly. It may become unstable, or not to oscillate at all, but it
may.
> >
> >
> >>> Sorry, I have just only  started with microchips  - so a lot  of new
> >>> knowledge for me to learn.
> >> It's not about learing PICs, it's about telling everything and
> >> not hiding details. :-)
> >
> >
> > By my experience with teaching newbies in electronics and
> > microcontrollers, it takes time to notice that there's missing
information.
> > Because of this, I generally take it easy with them.
> >
> >
> > Isaac
> >
> --=20
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist


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