I'm baaaaaaack!  Quick revival, I've been searching high and low for
appropriate crystals at appropriate prices(!), and the major issue is that
most "cheap" ones aren't listing a load capacitance!

Is there any way of determining the load capacitance, or more accurately
what the appropriate load capacitor values should be?  Or is the "standard
22pf caps" "close enough"?

As an example, the cheapest I can source small quantities (5x,10x,50x) of
a 3225 crystal (or similar size +/- a few mm) with a KNOWN load
capacitance, is about $1.30 each.  If I source those with UNKNOWN load
capacitance (and no known brand), then it is more like $0.40 each.
As an aside, the likes of Digikey/Mouser/Farnell want to charge in the
order of $30+ to ship a couple of crystals!  RS, on the other hand, have a
local office with free pickup.

I'm primarily doing 8bit sound playback, interrupting @ 16kHz, with some
I2C to an accelerometer and SPI (or nearly-SPI) to other devices; the
RS232 comms is primarily for debugging and development, obtaining raw
accel data for analysis for future function incorporation, so comms
doesn't need to be the fastest available (code will also be stripped back
to bare basics at this time).

I do prefer the idea of having an external crystal or resonator, I can't
remember why off-hand but there was some valid reasoning...

Lee

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