On Sat, Mar 04, 2017 at 07:41:57PM -0700, Brian Gieryk wrote: > Running latest chrony(d)(c) with a raspberry Pi 3(B) and a DS3231 (DS1307 > with temp comp) and GPS with PPS on GPIO pin 18. > > PPS and GPS work fine (thanx to the list!). > > Now I added an RTC module. > > Still have all good PPS etc. > > After restarting chronyd first then gpsd everything starts up fine. Good > data on gpsmon, ppstest. > > When doing a chronyc sources, starts out with both RTC and PPS having a ?. > After a short time, it will pick up the RTC (*) then the PPS (*) and RTC(-). > Then very shortly thereafter both (RTC and PPS) switch to falseticker (X) > status, never to recover.
If I understand it correctly, the RTC is not synchronized to anything but is used as a time source (a PPS refclock?) mixed with the GPS PPS? That won't work as the sources don't agree on what time it is. A better way would be to use it as a tempcomp input to adjust the frequency of the system clock. Dan Drown has some very interesting posts about that: http://blog.dan.drown.org/frequency-synchronization-without-phase-in-ntp/ -- Miroslav Lichvar -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.