Re: [chrony-users] Issue with chrony dropping PPS signal

[Bill Unruh <unruh@xxxxxxxxxxxxxx>]

On some rtcs, it will issue an interrupt when the second rolls over. So it
will be like a PPS signal. Or you can run a poll loop near the second (on your
machine which should be pretty well in time ) to see exactly when the second
rolls over. A bit messy and expensive. And as I said, I do not believe that
the rtc will keep good enough time for your requirements, but you would have
to test that.

Getting GPS to be reliable is certainly a better option.

With GPS you should get microsecond accuracy.



On Mon, 8 Mar 2021, Vincenzo Miceli wrote:

> [CAUTION: Non-UBC Email] Thanks Miroslav, Bill, Hal,
>
> I'm dropping the hardware RTC as a backup precision time keeper as the one I have (DS3231) doesn't provide sub-second resolution in
> its register.... I would have to use its square wave output etc... which make the whole thing impractical. I'll be testing a better
> antenna and relocate the GPS receiver outside with better view of the southern sky (that's the intended use anyway). 
> I will read about the maxclockerror directive and see if that can be used  in case of GNSS issues.
>
> Thank you all,
>
> Enzo
>
> ______________________________________________________________________________________________________________________________________
> From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
> Sent: Monday 8 March 2021 08:30
> To: chrony-users@xxxxxxxxxxxxxxxxxxxx <chrony-users@xxxxxxxxxxxxxxxxxxxx>
> Subject: Re: [chrony-users] Issue with chrony dropping PPS signal  
> On Fri, Mar 05, 2021 at 03:59:26PM +0000, Vincenzo Miceli wrote:
> > Is there any way for chrony to stop provide time to clients if the PPS signal is lost?
>
> No, the server will just keep increasing its root dispersion reported
> to its clients, following the NTPv4 specification. The minimum rate
> can be configured with the maxclockerror directive.
>
> --
> Miroslav Lichvar
>
>
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