Re: Help needed to configure and compile gpsd to run on a Raspberry Pi 4 and NOT use systemd

[Frank Nicholas]

Exactly - does crony read this directly?  If not, how does the system know 
which time the “0”/start of the second is from?

How can you trust PPS, without knowing what date/time the PPS is relative to?

Thanks,
Frank

> On Nov 13, 2024, at 12:07 PM, Robert P Schaefer <rps@mit.edu> wrote:
> 
> with ublox, this would be a NMEA time message
> 
>> On Nov 13, 2024, at 12:04 PM, Frank Nicholas 
>> <frank@nicholasfamilycentral.com> wrote:
>> 
>> I believe PPS just gives you the “0”/start of each second.  How do you get 
>> the actual time it is reporting the “0”/start of?
>> 
>> Thanks,
>> Frank
>> 
>>> On Nov 13, 2024, at 11:38 AM, tangoing.mill745@aceecat.org wrote:
>>> 
>>> On Tue, Nov 12, 2024 at 09:28:31PM GMT, Mick Durkin wrote:
>>> 
>>>> My son wanted to have a timeserver on his internal network, so he
>>>> decided to go down the path of using a ublox type GPS module with a
>>>> serial interface and a PPS signal driving gpsd on a Raspberry Pi 4.
>>> 
>>> I promise this will be the last time I say this here, but clearly
>>> this is relevant to the OP situation.
>>> 
>>> gpsd is *not needed* to use a PPS source with Linux and chrony, and
>>> that includes the Raspberry OS. Just add a line like this to
>>> chrony.conf:
>>> 
>>> refclock PPS /dev/pps0 refid PPS0
>>> 
>>> I do not know if other ntp implementations like ntpsec have something
>>> similar, but I doubt it.
>>> 
>>> -- 
>>> Ian
>>> 
>> 
>> 
>