[time-nuts] Re: Microcontroller based frequency divider

[Gilles Clement]

I use « AVR-DIV » with ATTiny13a.
Interest is that it works with one clock cycle instructions (instead of 4 clock cycles for PIC). So any integer divider can be used.

Seems to work as well as PIC although I did’nt formally verify.

Gilles.


> Le 30 avr. 2022 à 23:55, Simon Merrett <smerrett79 at hotmail.com> a écrit :
> 
> 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
> 
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
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