> This came up in a beginner thread, but I'd like to get a definitive
> answer. Can I use VCC for the "ground" side of the crystal's
> phase shift caps? Theory says VCC is equivilent to ground from
> an AC perspective, and it would certainly make most PCB layouts
> a bit cleaner, but I'd like to hear from someone who has done this
> regularly and thinks that it actually
> works!
>
> Thanks
> Bill W

The easy way would be to try it and see what happens. I don't recall
ever seeing a micro or (parallel) oscillator that used caps to Vcc,
apart from that one Microchip circuit. Microchip's own guide to PIC
oscillators

http://www.microchip.com/download/appnote/rfpic/00826a.pdf

has no mention that I can see of caps to Vcc, and all diagrams show
caps to ground. So does the Mid-range Manual, and several other MC
pdfs I looked through. Maybe caps to Vcc is acceptable, but putting
them to ground is certainly the prevailing method. Mention is made in
the M-RM of the quiescent charging of caps during SLEEP and how
that can make oscillator start-up difficult. Perhaps that's a clue

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