[time-nuts] Re: Microcontroller based frequency divider

[Simon Merrett]

I know they were unavailable from one of my usual distributors when I checked last week. I also prefer surface mount parts and that narrows the availability somewhat but isn't a red line for me.

I'm very open to the idea that the PIC12F was a one-off in terms of the timing performance. But I have also heard that modern silicon processes could yield better results, based on informed conjecture. I am more familiar with eg the newer ATtiny series of chips and the Microchip Cortex M series parts. I realise that datasheet figures are often just an envelope of performance and they don't mention jitter but the PIC12F states something like a 10 ns gpio rise time and a recent ATtiny specs something like 1.5 ns. For the simpler (AVR, not Arm) parts, maybe there is a whole bunch which would be suitable. I'm happy to build some but I can't (yet) do the testing to see if they are viable. If there are other contenders I'd be happy to look at them too.

Simon
________________________________
From: Clint Jay <cjaysharp at gmail.com>
Sent: Saturday, April 30, 2022 8:33:17 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: [time-nuts] Re: Microcontroller based frequency divider

I think the reason the PICDiv is so well regarded is because of the
specific chips used and the way the timers etc. are implemented in them.

So, an alternate chip outside of the Microchip PIC range just might not be
capable of the performance.

Are they in short supply?



On Sat, 30 Apr 2022 at 20:29, Simon Merrett <smerrett79 at hotmail.com> wrote:

> Dear time nuts,
>
> I'm now on this list thanks to leapseconds.com where I went looking for
> the picDIV. A wonderful device. I have a project coming up where I plan to
> cut my time-teeth and think a picDIV will be just right for one of the
> stages.
>
> However, with components in short supply these days, I wondered if a
> similar approach could be taken on an alternate, or a few alternative,
> part(s). I have a Leo Bodnar GPSDO but only a 50 MHz bandwidth oscilloscope
> (Rigol DS1054Z), which I cannot think will be sufficient to characterise an
> alternative implementation.
>
> So I was wondering if there are any time nuts who might have the
> wherewithal to measure an alternative microcontroller frequency divider
> implementation. I would think a 10 MHz division to 1PPS. I'd like to know
> jitter and delay/offset (I'm afraid I'm still not up on all the terminology
> - feel free to educate me please!) to around 100 ps accuracy (I think I
> need nanosecond accuracy in my project). I would obviously pay for shipping
> the parts to be tested and the parts themselves (most likely with power and
> coaxial signal connectors on a PCB). Please comment, even if you aren't in
> a position to offer measurement.
>
> Thank you for this community.
>
> Yours,
>
> Simon
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--
Clint. M0UAW IO83

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