Searching \ for '500kHz ceramic resonator or 4MHz quartz crystal?' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/timers.htm?key=resonator
Search entire site for: '500kHz ceramic resonator or 4MHz quartz crystal?'.

Truncated match.
PICList Thread
'500kHz ceramic resonator or 4MHz quartz crystal?'
2000\04\13@142053 by briang

flavicon
face
We recently designed a board with a PIC16C72A on it which ran the chip
at 500kHz using a ceramic resonator and two 68pF capacitors on OSC1 and
OSC2.

The board seemed to run perfectly on the bench but we had major problems
with - we assume - interference crashing and corrupting the processor
when the board was installed in the machine it was designed for.

After trying everything we could think of we eventually tried modifying
the code and running the processor at 4MHz with a quartz crystal and two
22pF capacitors and magically all the problems went away!

My boss is now keen to change all ceramic resonators in our products for
quartz crystals but I think at worst we probably only need to avoid
using ceramic resonators with PIC chips.

Can anyone offer any information to help me understand this incident and
decide what our policy on ceramic resonators should be in the future?

Brian G.
spam_OUTbriangTakeThisOuTspamcix.co.uk

2000\04\13@155122 by Dan Michaels

flavicon
face
Brian wrote:
>We recently designed a board with a PIC16C72A on it which ran the chip
>at 500kHz using a ceramic resonator and two 68pF capacitors on OSC1 and
>OSC2.
>
....
>After trying everything we could think of we eventually tried modifying
>the code and running the processor at 4MHz with a quartz crystal and two
>22pF capacitors and magically all the problems went away!
>

Did you try one of the higher speed oscillator options with the res,
as some of the other threads have just mentioned? Might need a series
R to prevent overload.

2000\04\13@191234 by mike

flavicon
face
On Thu, 13 Apr 2000 19:19:00 +0100, you wrote:

{Quote hidden}

I think it was probably down to the use of a low frequency resonator
rather than a resonator as such - I've found units below 2MHz to be
rather tempramental. Higher freq ones are fine.  

More... (looser matching)
- Last day of these posts
- In 2000 , 2001 only
- Today
- New search...