[ntp:questions] SHM driver as a PPS source

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Thu Nov 24 21:00:51 UTC 2016

On 2016-11-24 05:49, folkert wrote:
> How can I tell NTPd that an SHM time source is actually a PPS and
> that it thus should combine it with some other sources? (an '*' +
> 'o' combination so to say)

Seems to be implied for paired gpsd SHM regions e.g.

server    minpoll 4 maxpoll 4
fudge    refid GPS time1 0.###

server    minpoll 4 maxpoll 4 prefer
fudge    refid PPS

Unit 0 is coarse time and output must *follow* closely *after*
unit 1 precise time output to get the correct seconds label.

Seems gpsd may connect /dev/gps0 interrupts to kernel pps and use
that, as it says the system must support kernel pps.

Use ntpshmmon to check SHM contents.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

More information about the questions mailing list