[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  127.127.28.0    minpoll 4 maxpoll 4
fudge   127.127.28.0    refid GPS time1 0.###

server  127.127.28.1    minpoll 4 maxpoll 4 prefer
fudge   127.127.28.1    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