[time-nuts] How to get 32.768KHz from 10MHz.
pico.2008 at sbcglobal.net
Sat Oct 25 19:30:25 UTC 2008
For those still interested in the 10 MHz to 32 KHz divider issue, I
offer the PIC source to a tested divider that runs in an 8-pin DIP
Tom Van Baak wrote:
> Since synchronization is more important than jitter in this
> application it's easy to generate 32 kHz from 10 MHz.
> A 10 MHz clock into a PIC gives a 400 ns/instruction time.
> To produce 32.768 kHz you flip an output pin put every 38
> instructions, except that 9632 times per second you make
> it 39 instructions instead.
> The result is 65536 bit flips per second (giving a frequency
> of exactly 32768 Hz) consuming 2 500 000 instructions per
> second. The output accuracy equals the input accuracy.
> The output jitter is as most 400 ns.
More information about the time-nuts