[time-nuts] What's the easiest way to divide by 10 forThunderbolt reference output?

Tom Van Baak tvb at LeapSecond.com
Tue Jul 24 18:50:29 UTC 2012


> John,
> 
> That's interesting to me. What exactly are the actual structural limitations of [that] pic?
> 
> -CH

The PIC has a 4:1 external clock / internal instruction cycle ratio so a software-based divider can't divide by a low number like 10. See www.LeapSecond.com/picdiv for details, and source code.

Although initially intended as a 1 PPS divider, the [re]programmable PIC and TAPR T2-Mini make a compact frequency divider solution for frequencies from once a day to 100 kHz.

As far as frequencies close to 10 MHz -- I assumed that division by 2 (e.g., 10 MHz -> 5 MHz) or division by 10 (e.g., 10 MHz -> 1 MHz) were simple to implement using a single IC (one flip-flop or decade counter). The '7490 or '390 come to mind.

/tvb




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