On January 4, 2006 12:33 am, Jinx wrote:
> Does it matter which capacitor (the one on OSC1 or OSC2)
> is variable to trim the crystal frequency?

The input is going to be fairly sensitive to change.
A variable trimmer cap is also sensitive to change, example temp.
Therefore, you should modify the output side.

The ucontroller oscillator is not that much different from an inverter 
oscillator.
Here's an example, which appears to show output modified as well.
http://www.ee.washington.edu/circuit_archive/circuits/F_ASCII_Schem.html#ASCIISCHEM_008

> I've looked in all the 
> MChip oscillator pdfs I can find but they don't say. Maybe it
> doesn't matter or maybe they left it out

They probably aren't expecting to see the frequency modified at the 
ucontroller.... in other words, you were thinking "outside the box" ;-)
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