[time-nuts] RTC DS3231: how well can it be regulated?

[ASSI]

I've got another batch of DS3231 RTC and this time they were DS3231M (not 
entirely unexpected).  These behave quite differently from the DS3231SN, which 
the datasheet says, but omits some of the details of:

- the TCXO tuning runs every second (not every 64s) and takes about 73ms
- the TCXO start is ~24ms after the PPS gets asserted
- there is quite a bit of jitter both on the PPS and the TCXO Start
- the mean / median of the TCXO start is not indicative of the PPS position
- the steps of the aging values is almost exactly the 0.12ppm datasheet value

Attached is a plot of the last 7 weeks of almost continuously monitoring it 
(and adjusting the aging values by hand to mostly keep it within ±5ms).


Regards,
Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Wavetables for the Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#BlofeldUserWavetables
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