On Wed, Mar 10, 2010 at 7:44 AM, m...@watty <[email protected]> wrote:
> > > On Mar 10, 1:21 pm, vasile surducan <[email protected]> wrote: > > > datasheet claims minimum calibration range of +/-2.8 seconds/month. > > It will depend ENTIRELY on: > 1) Quality / Accuracy of the 32.768 crystal > 2) Having a fine adjustment "trimmer capacitor" on the approriate > crystal/CPU Osc pin > This is not necessary since there is available a calibration register. > 3) Ambient temperature and variation of it. > > With inappropriate fixed capacitors and big temperature swing, I'm > sure you can make it as bad as 3 sec a day... > > With aged quality crystal, trimmed NPO adjustable capacitor and 25 to > 35 ambient at crystal (with only a few degrees variation), it's likely > that better than 1s a month is possible. > > Watch on wrist keeps best time next to skin if never taken off and > crystal adjustable Cap was trimmed for about 30 deg C and back metal > but casing plastic :-) > Yes, that's known. > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<jallib%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > > -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
