Lpc2000

From: "microbit" <microbit@...>
> Crystals that are driven too hard age fast, will excessively drift in
frequency much quicker
> (not such an issue w/ MCU in general I guess), can also go in overtone
over Vcc
> and even just break.

Literally - I've seen it happen before my eyes, with the old Statek crystals
in a ceramic case with glass lid. They were $10 back then   :-(

About the biasing resistor:
> Can be as low as 1 Mohm though :-)

Only if needed when the input has leakage - a lower value also lowers the
change of oscillation (impedance of the inverting feedback path through the
crystal should be lower than that though this resistor, and if they are
close together the oscillator stage needs more gain).

Regards,
Arie de Muynck