I have a 18F252, programmed for HS, that works fine with a 20mhz xtal, bu=
t I
have tried two different 40mhz xtals without success. One won=92t oscilla=
tor
(I tried series resistors from 1-330k and caps from 10pF-47pf) and the ot=
her
oscillates at 13.3mhz (1/3 of 40) (also tried all the various res and cap
values).  What makes an oscillator work at 1/3 the rated frequency?

P.S. I thought for sure I had seen a similar issue discussed in the past,
but I was unable find anything relevant in the archives (I found mostly
stuff on driving multiple pics from one xtal).  And I read the oscillator
section of the beginner=92s checklist.  So sorry if this is a common
situation.

--BobG

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics