[volt-nuts] 1PPS to 32.768 khz

Mark Sims holrum at hotmail.com
Wed Oct 19 22:46:46 EDT 2016

Yep,  a single 8-pin chip with 4 pins used (VCC, GND, in, out).   I did something very similar to this in an ATTINY-13 (OK I used a TINY85, but the code was less than 200 bytes long).   I can't share it since somebody paid for the thing and it is not directly applicable,  but it is rather trivial to do.   

If you want to get fancy,  you can have the thing self-calibrate the pulse generation loop to optimize the output pulse timing to minimize the "dead time" between the last pulse out and the next 1PPS pulse and compensate for RC oscillator drift/variation... but that is an unnecessary complication for a wall clock display.  Just hard-code it and leave enough margin for device variation/drift.


>  Some of them come with builtin R-C  oscillators so the parts count would be really low.

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