Your not just mating the XTAL to the CPU. The traces in between add
several pF of capacitance as well. So find an XTAL with 10-12pF
(12.5pF is common).

Eric

amerdsp wrote:
> Hello,
>   I am trying to use a surface mount crystal for the RTC clock on the
> STR912F microcontroller.  The datasheet states that the load
> capacitance is 8pF (Typ).  Unfortunately, I am unable to find an SMD
> crystal with that load capacitance.  I can, however, find 7pF and
> 9pF.  Can they be used?  Any hints or ideas?
> 
> Thank you,
> 
> A
No, Yes. Look at other crystals!
-- 
Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:

Hello,
  I am trying to use a surface mount crystal for the RTC clock on the
STR912F microcontroller.  The datasheet states that the load
capacitance is 8pF (Typ).  Unfortunately, I am unable to find an SMD
crystal with that load capacitance.  I can, however, find 7pF and
9pF.  Can they be used?  Any hints or ideas?

Thank you,

A