William,

 Try putting a 10 Meg resistor across the crystal leads.
 What this does is when the part is powered up, current
 flow causes a voltage drop across the resistor. This
 difference in voltage causes an out of balance condition.
 This out of balance condition causes the oscillator to start
 more reliably.  As a matter of fact, it should start every
 time.

 Hope this helps.


                                       Regards,

                                         Jim

>Greetings ALL:
>
>Does anyone out there have practical experience (I've already read all
>the app-notes, talked to the FAI's, the factory techs, etc. etc ad
>nauseum.) with getting 32.768 KHz watch crystals to start reliably with
>the PIC's?
>
>
>I'm working primarily with 508/9's and 54's.  In the case of the 509's
>and '54's, I have a circuit in production that works perfectly,
>repeatably, and starts every time--HOWEVER when I plug in a
>509<bold>B</bold> the oscillator doesn't.  Ditto with the 54's--a stock
>54 or 54A seems to work fine, the 54B's refuse to oscillate in the same
>circuit.
>
>
>I am using standard C type crystals from Digikey SE3202 (Epson C-002RX
>32Khz 20PPM, 12.5 pF 30KOhms typ. series resistance)
>
>with 12 pF load caps in the standard two caps to ground configuration
>straight out of the data books and tech notes.
>
>
>QUESTION:  has anyone else encountered this behavior?  What did you do to
>fix it?
>
>Thanks,
>
>Kelly
>
>
>
>*******************************************************************************
*****

>
>All legitimate attachments to this email will be clearly identified in the
text.
>
>William K. Borsum, P.E.
>
>OEM Dataloggers and Instrumentation Systems
>
><<borsum@dascor.com> & <<www.dascor.com>
>