> Why would an ANDed oscillator be better than a simple pull-
> up/down?

The thinking being that if LED power is safely limited by an external
PWM signal, it doesn't matter if a logical drive signal gets stuck high.
Like the backplane on an LCD. Ideally you'd have a safety time-out,
for instance having to periodically pass through a particular section of
code to stop the PIC resetting via WDT or similar


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist