Elapsed Timer Demo

[sayzer]

Hi crematory,

That depends on the accuracy of the crystal being used, and the ambient temperature.
And, you'd probably need to have some kind of backup battery, to keep it going during any power outages.

I think I calculated it at around +/- 4 minutes per year with a standard 20mhz crystal. It was around 20 seconds/year with one of those temperature compensated TTL Oscillators.
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Hi Darrel,

Could you suggest a good "one of those temperature compensated TTL Oscillators" please ?

Also, if aging for an oscillator is stated, say, +/-5ppm a year or +/- 100ppm a year, what would it mean in your elapsed timer application?

Last question, if I modify your routine to work for 100years, forget about power failures etc., and use a good osc as you may suggest, what would be a possible problem as years pass by?

Thanks.


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