[ntp:questions] Getting PPS to work with Oncore ref clock

Chris Albertson albertson.chris at gmail.com
Fri Feb 18 06:52:02 UTC 2011


On Thu, Feb 17, 2011 at 4:40 AM, Mike S <mikes at flatsurface.com> wrote:
> At 01:16 AM 2/17/2011, Chris Albertson wrote...

> Get your source working with ppstest working before you try NTP. When your
> PPS source is set up and working, you should get something like:
>
> locke:/usr/src/pps-tools# ./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 1297945532.000064855, sequence: 1967640 - clear
>  0.000000000, sequence: 0
> source 0 - assert 1297945533.000045499, sequence: 1967641 - clear
>  0.000000000, sequence: 0

I stopped ntpd then ran ppstest.  It produces the following:

sudo /usr/src/pps-tools/ppstest /dev/oncore.pps.0
trying PPS source "/dev/oncore.pps.0"
found PPS source "/dev/oncore.pps.0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1298011155.999464502, sequence: 64785 - clear
1297840243.197985597, sequence: 36
source 0 - assert 1298011156.999460038, sequence: 64786 - clear
1297840243.197985597, sequence: 36
source 0 - assert 1298011157.999458883, sequence: 64787 - clear
1297840243.197985597, sequence: 36
source 0 - assert 1298011158.999457012, sequence: 64788 - clear
1297840243.197985597, sequence: 36

I don't know what all of this means but I see the time increment by
about 1 second every second

Here is the ntp.conf file.  I've tried to keep it small and simple for now

$ cat /etc/ntp.conf
driftfile /var/lib/ntp/ntp.drift
# Enable this if you want statistics to be logged.
statsdir /var/log/ntpstats/
logconfig =all
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
disable auth
# Connect to Oncore UT+ GPS
server 127.127.30.0
server 0.us.pool.ntp.org
server 1.us.pool.ntp.org
server 2.us.pool.ntp.org

And the the ntp.oncore.0 file
$ cat ntp.oncore.0
MODE 2
SHMEM /var/log/ntpstats/ONCORE
POSN3D

I doubt the SHMEM line is correct but I'll worry about that later

-- 
=====
Chris Albertson
Redondo Beach, California



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