Clock - Internal RC 8 MHz oscillator
Where could we see the schematics? Preferably in Eagle format.And where can we buy this?
for low-power have a look at this development too :http://news.jeelabs.org/2010/09/03/jeenode-goes-solar/http://news.jeelabs.org/2010/09/02/sending-packets-without-battery/and http://news.jeelabs.org/2010/09/06/running-off-a-single-aa-battery/
I'm quite sure it needs calibration
If you decide to try your hand at calibrating I would certainly like to hear how you get on.
Hmm, the processor has a 32kHz crystal, so it should be able to automatically calibrate. I think there exists an application note that describes this process but I seem to be able to find it with Google right now.
It includes interchangeable power shields for various sources (solar/battery, piezo, peltier, RF), but nothing explicitly for charging LiIon yet.
Did you get a chance to measure the sleep current on this design?
Do you need the 22pF caps on the watch xtal, or is that in case you can't find a 6pF xtal.
Higher load capacitance implies less pullability. Thus in doubt better precision.
If you go for lower load you will get more pullability and thus less precision / stability.