At 06:00 PM 6/18/96 EST, you wrote:

>4% is awfully bad for an xtal.  They are usually spec'd to within 100ppm
>(0.01%) if correct loading is used.  Try a different xtal.  Note that there
>are 2 basic types of xtal: series and parallel resonant.  I can't remember
>which, but one should be in an inverting loop and the other in a non-inverting
>loop.  Don't know which type the PIC is expecting.
>
>>
That's where  I think I shot my self in the foot.
I order the crystals and by mistake, I just double checked,
got series cut for the 4 mhz ones.  Thanks for a quick answer!


>If used correctly, the xtal will be within 0.01%.  Try adding a series resistor
>since the xtal may be being grossly overdriven.  Perhaps the seal is broken
>(although I would expect moisture on the quartz would slow it down not
>speed it up as you state).
>
>>
>> I really thought I could just grab a 4mhz rock and a couple caps ant it would
>> be at least as close as I need. Should I consider using a canned dip
> oscillator?
>>
>
>That would certainly work.

I believe my 10mhz crystals are the right cut and I will redo the delay loops
and try it out again
>
>>
>> Another question is can you use a solder less breadboard (I just got one of
> the
>> E.N.D. unit's) and a 20mhz clock on a 16c65 windowed part. I have concerns
> that
>> the oscillator will go nuts with all the stray coupling, and I will need 0.1%
>> accuracy on that unit too.
>>
>
>I have had no problems with 4MHz logic (was a Z80 system) done up on a
>breadboard.  Using a frequency meter and changing loading capacitance by
>a few 10's of pF produced only a few 100Hz difference at 4MHz.
>
>Regards,
>SJH
>Canberra, Australia
>

Thanks again for the reply.

I am sorry I wasted the list's time on this, but a quick look in the book
showed
nice charts for RC oscillators and resonators, but only a more careful reading
spotted the series cut warning. Its near the start of section 13 of the
16c6x book.