Henry Carl Ott wrote:

>  I've also connected the center pin of ceramic resonators to VCC instead of
> GND. However I've only done this with prototypes when it simplified the PCB
> design.
>  Does anybody know if there is a problem with this practice in production
> quantities? I'm wondering about stability and perhaps problems with the
> oscillator starting.

Well, I suspect that others on this list may not agree with me, but I
would advise against it. Other than the obvious issue of VDD line noise
being introduced into the oscillator circuit, the small amount of
leakage current intoduced may cause some problems during start up under
marginal conditions. Now, before someone tells me that "thats not
likely" let me relate the following: 10+ years ago the Intersil 80C35
microcontroller used to have oscillator start up problems. The
recommended solution? Tie the caps to VCC instead of GND! I had to spec
out the part as we were unwilling to rework the PCB.

--
Regards, Dana Frank Raymond