Re: [chrony-users] Debugging PPS messages in chrony

[Rob Janssen <chrony-users@xxxxxxxxx>]

Morten

You cannot have only a PPS source, because that does not give you absolute time information, only modulo-1-second information.
So when you use PPS you always need to add another source.
That can be a network source (NTP) with server or pool, or you can use a serial port (NMEA) to the GPS device.
When you have internet or the PPS source provides NTP, it is preferable to use that.
It is also possible to use SHM for that, but you need another program that puts the time info into SHM.
Furthermore, when you start things using systemd it is tricky because systemd provides no sequence of starting
daemons, and you have to start the program for SHM and the pps (ldattach) BEFORE starting chrony!

Rob

On 2024-07-08 10:07, Morten Nissov wrote:
> Hi all,
>
> I am looking at setting up a relatively custom thing for timekeeping, which attempts to function as a GPS (in terms of PPS + unix stamp) using an RTC and microcontroller.
>

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