Both, but mostly because the micro often dies during thunderstorms.
> And here I thought a PLL losing sync when someone touches it
with their fingers was bad...
(We have some synthesizer ICs from a well-known manufacturer that exhibit spur levels anywhere from about 0 to -60dBc and we're at the point where we're about 99% convinced that we're getting bad ICs... a major part of the indictment being that, when you put the PFD's output into tri-state, the VCO runs off like a rabbit from a dog rather than just drifting away relatively slow as you'd expect...)