Adam,

questions
1. are you using water soluble solder?
2. what value caps your resonator have?
3. does it work with resonator middle pin disconnected?
4. did you try crystal?

what I recommend.
1. remove the resonator and use external oscillator connecting
   to osc in and see if your pic is running ok.
2. make sure you do not have any resistance.
3. clean the board
4. change the pic just in case

Andre 



-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
Of Adam stambler
Sent: Friday, December 08, 2006 9:04 AM
To: Microcontroller discussion list - Public.
Subject: [PIC] Oscilator Problem


Hi, I was wondering if anyone could provide some oscillator guidance.  I am
trying to run a 16f690 off a 20 mgherz ceramic resonator with built in
capacitors.

I think i have all my my programming correct, but when I go to turn it on,
it does not work.  The oscillator does not start up.  However, if I try to
measure the voltage with my multimeter and touch the Clock input pin, the
PIC starts to work.  There is about 2.3V on the clock output and input pin
.

Right now i have a 1 mega Ohm resistor across the input and output leads of
the resonator like the datasheet said for it to have. I am running the
resonator in HS mode.

My guess is that my programming is correct but there is not enough drive to
get the oscillator going.  Unfortunately, I have no idea about how to fix
the problem.  This is my first oscillator circuit which I am using for a
school project.

Anyone have any ideas?

Thanks,
Adam Stambler
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