Problem with crystal for PIC16F876

V

vthach

New Member

• Mar 30, 2010

• #1

Hello,
I am a final year student in electronic engineering, I have a problem with the oscillation in my circuit, when i want to set the oscialltion frequency using a 4MHz crystal and associate with 2 15pF capacitors.
I don't get any oscillation.
Can anyone help me please

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Mar 30, 2010

• #2

Have you set the config fuses correctly?, if you have then you're probably connecting it wrongly - check my tutorial hardware.

 

V

vthach

New Member

• Mar 30, 2010

• #3

Thank you for your fast reply.
Hmmm, well what do you mean by the config fuses, sorry as I am french we do not really use the same technical vocabulary, is it possible to get the link of your tutorial hardware?

 

V

vthach

New Member

• Mar 30, 2010

• #4

Well, I just found out your tutoral hardware and i Config my hardware the same way as yours.

 

V

vthach

New Member

• Mar 30, 2010

• #5

All the connection looks ok, but I still don't get anything

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Mar 30, 2010

• #6

How do you know you don't get anything?.

 

V

vthach

New Member

• Mar 30, 2010

• #7

I am using a probe with an oscilloscope to check the crystal, but I finally solve my problem.
It was due to the pp3v program which I am using to load the program into the PIC, the default mode is RC and I didn't change it to Xtal.
Thanks for your help anyway

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Mar 30, 2010

• #8

Be aware that you MUST use a x10 probe when scoping the crystal, a normal x1 probe often stops it.