On 7/14/05, Wouter van Ooijen <wouter@voti.nl> wrote:
> > BTW, running those numbers with the *maximum* Rs of Mark's 
> > crystal (taken
> > from the datasheet) and a calculated load capacitance with 33pF caps
> > (calculated CL = 22pF) yields an estimated maximum drive 
> > power of 3.8mW, well
> > above the datasheet 1mW maximum rating of the crystal. That's 
> > the problem,
> > Euros to donuts.
> 
> OK Sherlock, you convinced me, thats the problem. But what's the
> solution?

  There are three solutions and both are nasty:
1. use a bigger crystal, bigger as dimension and as disipated power
2. use a low power cmos circuit to make it oscillate, other than the
PIC has inside
3. compensate a part of a crystal dissipated power on to a series
resitor (but do not try this without measurements, so buy a good scope
with real probes)

haven't you left yet into holiday ?
:)
cheers,
Vasile

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