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.
As a result I cannot use gpsd, my intention was to supply the PPS on a GPIO pin and transfer the corresponding timestamp to the SHM location. The PPS signal is routed corrected, as can be seen by $ sudo ppstest /dev/pps0 trying PPS source "/dev/pps0" found PPS source "/dev/pps0" ok, found 1 source(s), now start fetching data... source 0 - assert 1720367204.484611266, sequence: 415 - clear 0.000000000, sequence: 0 source 0 - assert 1720367205.484547142, sequence: 416 - clear 0.000000000, sequence: 0 source 0 - assert 1720367206.484646017, sequence: 417 - clear 0.000000000, sequence: 0 But it seems like this is not seen by chrony at all, as far as I know it wants the SHM update to actually synchronize, but when I added that it wasn't working so I'm trying to peel back the layers. Can I see confirmation anywhere that chrony registers the PPS by itself? My chrony config is loosely based on the default: $ cat /etc/chrony/chrony.conf # Welcome to the chrony configuration file. See chrony.conf(5) for more # information about usuable directives. # This will use (up to): # - 4 sources from ntp.ubuntu.com which some are ipv6 enabled # - 2 sources from 2.ubuntu.pool.ntp.org which is ipv6 enabled as well # - 1 source from [01].ubuntu.pool.ntp.org each (ipv4 only atm) # This means by default, up to 6 dual-stack and up to 2 additional IPv4-only # sources will be used. # At the same time it retains some protection against one of the entries being # down (compare to just using one of the lines). See (LP: #1754358) for the # discussion. # # About using servers from the NTP Pool Project in general see (LP: #104525). # Approved by Ubuntu Technical Board on 2011-02-08. # See http://www.pool.ntp.org/join.html for more information. #pool ntp.ubuntu.com iburst maxsources 4 #pool 0.ubuntu.pool.ntp.org iburst maxsources 1 #pool 1.ubuntu.pool.ntp.org iburst maxsources 1 #pool 2.ubuntu.pool.ntp.org iburst maxsources 2 refclock PPS /dev/pps0 refid PPS trust prefer #refclock SHM 2:perm=0666 delay 0.5 refid GPS noselect # This directive specify the location of the file containing ID/key pairs for # NTP authentication. keyfile /etc/chrony/chrony.keys # This directive specify the file into which chronyd will store the rate # information. #driftfile /var/lib/chrony/chrony.drift # Uncomment the following line to turn logging on. log tracking measurements statistics refclocks # Log files location. logdir /var/log/chrony # Stop bad estimates upsetting machine clock. maxupdateskew 100.0 # This directive enables kernel synchronisation (every 11 minutes) of the # real-time clock. Note that it can’t be used along with the 'rtcfile' directive. rtcsync # Step the system clock instead of slewing it if the adjustment is larger than # one second, but only in the first three clock updates. makestep 1 3 Systemctl status also shows some difficulty opening the log file, I'm not 100% sure the cause for this as the directory exists $ systemctl status chrony ● chrony.service - chrony, an NTP client/server Loaded: loaded (/lib/systemd/system/chrony.service; enabled; vendor preset: enabled) Active: active (running) since Sun 2024-07-07 17:45:20 CEST; 4min 5s ago Docs: man:chronyd(8) man:chronyc(1) man:chrony.conf(5) Process: 1191 ExecStart=/usr/lib/systemd/scripts/chronyd-starter.sh $DAEMON_OPTS (code=exited, status=0/SUCCESS) Process: 1198 ExecStartPost=/usr/lib/chrony/chrony-helper update-daemon (code=exited, status=0/SUCCESS) Main PID: 1196 (chronyd) Tasks: 2 (limit: 7967) Memory: 984.0K CGroup: /system.slice/chrony.service ├─1196 /usr/sbin/chronyd -F -1 └─1197 /usr/sbin/chronyd -F -1 Jul 07 17:45:20 Khadas systemd[1]: Starting chrony, an NTP client/server... Jul 07 17:45:20 Khadas chronyd[1196]: chronyd version 3.5 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SIGND +A> Jul 07 17:45:20 Khadas chronyd[1196]: Could not open log file /var/log/chrony/tracking.log Jul 07 17:45:20 Khadas chronyd[1196]: Loaded seccomp filter Jul 07 17:45:20 Khadas systemd[1]: Started chrony, an NTP client/server. But the directory is forever empty: $ ls /var/log -al | grep chrony drwxr-xr-x 2 119 129 4096 Aug 25 2020 chrony Sorry this became quite a long message, I wanted to be sure I captured everything. Best regards, Morten
