FreeBSD with Garmin GPS 18 LVC - NTP

This is a discussion on FreeBSD with Garmin GPS 18 LVC - NTP ; I'm trying to set up a server on a FreeBSD 6.2 system with the Garmin GPS 18 LVC as the PPS source. The system works fine using pool servers (PPS not enabled), but as soon as I try to use ...

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  1. FreeBSD with Garmin GPS 18 LVC

    I'm trying to set up a server on a FreeBSD 6.2 system with the Garmin
    GPS 18 LVC as the PPS source.

    The system works fine using pool servers (PPS not enabled), but as
    soon as I try to use the PPS signal, it acts as if ntpd is not
    running (I get a "localhost: timed out, nothing received" error on
    ntpq queries).

    I'm seeing good data from the GPS using minicom to look at the data
    stream and I have 4 - 6 satellites locked.

    My ntp.conf file contains:

    driftfile /etc/ntp.drift
    server 0.us.pool.ntp.org iburst
    server 1.us.pool.ntp.org iburst
    server 2.us.pool.ntp.org iburst
    #
    server 127.127.20.1 mode 1 prefer
    fudge 127.127.20.1 time1 0.000 flag3 1 refid PPS

    (when I comment out the last two lines, it works - obviously without
    the PPS ref)

    Suggestions?

    Keith

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    LtCol Keith E. Brandt, MD, MPH
    USAF-NASA Aerospace Medicine Liaison Officer
    Johnson Space Center, Houston, Texas
    wd9get@amsat.org

    Goodbye cruel world that was my home-
    there's cleaner space out here to roam
    Put my feet up on the moons of Mars-
    sit back, relax, and count the stars

    *This message transmitted with 100% recycled electrons

    _______________________________________________
    questions mailing list
    questions@lists.ntp.isc.org
    https://lists.ntp.isc.org/mailman/listinfo/questions


  2. Re: FreeBSD with Garmin GPS 18 LVC

    Keith,

    You have seen http://ntp.isc.org/Support/ConfiguringGarminRefclocks, right?

    You have built and installed a PPS-aware kernel, right?

    Are there any messages in /var/log/messages within a few minutes' time of
    ntpd starting?

    H

  3. Re: FreeBSD with Garmin GPS 18 LVC

    Keith E. Brandt, M.D. wrote:
    > I'm trying to set up a server on a FreeBSD 6.2 system with the Garmin
    > GPS 18 LVC as the PPS source.
    >
    > The system works fine using pool servers (PPS not enabled), but as
    > soon as I try to use the PPS signal, it acts as if ntpd is not
    > running (I get a "localhost: timed out, nothing received" error on
    > ntpq queries).

    []

    > Suggestions?
    >
    > Keith


    If it helps, my own experiences with FreeBSD 5.4 are here:

    http://www.david-taylor.myby.co.uk/n...SD-GPS-PPS.htm

    Cheers,
    David



  4. Re: FreeBSD with Garmin GPS 18 LVC

    David J Taylor wrote:
    > Keith E. Brandt, M.D. wrote:
    >> I'm trying to set up a server on a FreeBSD 6.2 system with the Garmin
    >> GPS 18 LVC as the PPS source.
    >>
    >> The system works fine using pool servers (PPS not enabled), but as
    >> soon as I try to use the PPS signal, it acts as if ntpd is not
    >> running (I get a "localhost: timed out, nothing received" error on
    >> ntpq queries).

    > []
    >
    >> Suggestions?
    >>
    >> Keith

    >
    > If it helps, my own experiences with FreeBSD 5.4 are here:
    >
    > http://www.david-taylor.myby.co.uk/n...SD-GPS-PPS.htm


    I have had such a system running on FreeBSD 6.1 for about a year.
    Nothing fancy about getting it to run except the need for dynamically
    re-creating the symlink to the /dev/gps0 device after each reboot.

    Terje

    --
    -
    "almost all programming can be viewed as an exercise in caching"

  5. Re: FreeBSD with Garmin GPS 18 LVC

    Keith E. Brandt, M.D. wrote:
    > I'm trying to set up a server on a FreeBSD 6.2 system with the Garmin
    > GPS 18 LVC as the PPS source.
    >
    > The system works fine using pool servers (PPS not enabled), but as
    > soon as I try to use the PPS signal, it acts as if ntpd is not
    > running (I get a "localhost: timed out, nothing received" error on
    > ntpq queries).
    >
    > I'm seeing good data from the GPS using minicom to look at the data
    > stream and I have 4 - 6 satellites locked.
    >
    > My ntp.conf file contains:
    >
    > driftfile /etc/ntp.drift
    > server 0.us.pool.ntp.org iburst
    > server 1.us.pool.ntp.org iburst
    > server 2.us.pool.ntp.org iburst
    > #
    > server 127.127.20.1 mode 1 prefer
    > fudge 127.127.20.1 time1 0.000 flag3 1 refid PPS
    >
    > (when I comment out the last two lines, it works - obviously without
    > the PPS ref)
    >
    > Suggestions?
    >
    > Keith


    Read David's page and take Harlan's advice from this thread. If you are
    running a stock kernel and haven't set PPS_SYNC as outlined in David's
    page, leave the "flag3 1" out of the fudge line. The stock kernel
    doesn't support hardpps, but the kernel does support PPSAPI so that ntpd
    can still use the PPS.

    Maybe the PPS output is turned off. Neither ntpd nor FreeBSD seem all
    that happy when it's configured for a PPS and one is not present. The
    relevant sentences are these:

    "$PGRMCE*0E" to make the GPS output the current PPS and other
    settings. Field 12 is PPS output and Field 13 is PPS pulse length.

    "$PGRMC,,,,,,,,,,,,2*79" to activate the PPS output, and

    "$PGRMI,,,,,,,R*3F" to do a soft reset of the GPS.

    Other than that, check your serial ports, GPS settings, and symbolic
    links. For "server 127.127.20.1", the NMEA driver expects /dev/gps1 to
    point to your serial port, and both the serial port and the GPS should
    be set to 4800 baud. All of this can be changed later--with maybe one
    tweak to ntpd/refclock_nmea.c of the ntpd source code--but first try to
    get it running at 4800 baud.

    Michael

  6. Re: FreeBSD with Garmin GPS 18 LVC

    >>> In article , Terje Mathisen writes:

    Terje> I have had such a system running on FreeBSD 6.1 for about a
    Terje> year. Nothing fancy about getting it to run except the need for
    Terje> dynamically re-creating the symlink to the /dev/gps0 device after
    Terje> each reboot.

    Have you edited /etc/devfs.conf ?

    If you look at /etc/rc.d/ntp you will see that it will start up after devfs
    has been run.

    H

  7. Re: FreeBSD with Garmin GPS 18 LVC

    Thanks all for the help. I didn't have a link to GPS1, so fixing that
    got it running.

    However...

    It worked fine for a while, then I rebooted for other reasons and
    anytime I try to run ntpq -p or ntpdc -c peers, ntpd crashes with the
    error: "uid0: exited on signal 11 (core dumped)". If I put the pool
    servers in ntp.conf before the gps, ntpq -p lists their stats then
    dies when it gets to the gps. If I list the gps first, it dies after
    printing the headers.

    As long as I don't run ntpq -p, it seems to be doing fine. ntpdc -c
    loopinfo is reporting single-digit microsecond offsets and frequency
    stability around 50 ppm. I've been successful at using it as a server
    for machines on my lan.

    A websearch for the specific error message wasn't revealing.

    Help??

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    LtCol Keith E. Brandt, MD, MPH
    USAF-NASA Aerospace Medicine Liaison Officer
    Johnson Space Center, Houston, Texas
    wd9get@amsat.org

    Goodbye cruel world that was my home-
    there's cleaner space out here to roam
    Put my feet up on the moons of Mars-
    sit back, relax, and count the stars

    *This message transmitted with 100% recycled electrons

    _______________________________________________
    questions mailing list
    questions@lists.ntp.isc.org
    https://lists.ntp.isc.org/mailman/listinfo/questions


  8. Re: FreeBSD with Garmin GPS 18 LVC

    On 2007-03-04, Harlan Stenn wrote:

    > Terje Mathisen wrote:
    >
    >> I have had such a system running on FreeBSD 6.1 for about a year.
    >> Nothing fancy about getting it to run except the need for dynamically
    >> re-creating the symlink to the /dev/gps0 device after each reboot.

    >
    > Have you edited /etc/devfs.conf ?


    What do you put there to cause the sym-link to be generated?

    --
    Steve Kostecke
    NTP Public Services Project - http://ntp.isc.org/

  9. Re: FreeBSD with Garmin GPS 18 LVC

    >>> In article , Steve Kostecke writes:

    Steve> On 2007-03-04, Harlan Stenn wrote:
    >> Terje Mathisen wrote:
    >>> I have had such a system running on FreeBSD 6.1 for about a year.
    >>> Nothing fancy about getting it to run except the need for dynamically
    >>> re-creating the symlink to the /dev/gps0 device after each reboot.

    >> Have you edited /etc/devfs.conf ?


    Steve> What do you put there to cause the sym-link to be generated?

    I added the following 2 lines on a FreeBSD5 system:

    link ttyd1 refclock-0
    link ttyd1 pps0

    H

  10. Re: FreeBSD with Garmin GPS 18 LVC

    >>> In article <20070304221717.0108C14350A@mail8.mdx.safepages.com>, wd9get@amsat.org (Keith E. Brandt, M.D.) writes:

    Keith> It worked fine for a while, then I rebooted for other reasons and
    Keith> anytime I try to run ntpq -p or ntpdc -c peers, ntpd crashes with the
    Keith> error: "uid0: exited on signal 11 (core dumped)". If I put the pool
    Keith> servers in ntp.conf before the gps, ntpq -p lists their stats then
    Keith> dies when it gets to the gps. If I list the gps first, it dies after
    Keith> printing the headers.

    Exactly what version of ntpd are you using?

    Can you try the latest ntp-dev tarball?

    Can you get a gdb traceback of the core file?

    H

  11. Re: FreeBSD with Garmin GPS 18 LVC

    Harlan Stenn wrote:
    >>>> In article , Terje Mathisen writes:

    >
    > Terje> I have had such a system running on FreeBSD 6.1 for about a
    > Terje> year. Nothing fancy about getting it to run except the need for
    > Terje> dynamically re-creating the symlink to the /dev/gps0 device after
    > Terje> each reboot.
    >
    > Have you edited /etc/devfs.conf ?


    No, I've been using /etc/rc.local instead.
    >
    > If you look at /etc/rc.d/ntp you will see that it will start up after devfs
    > has been run.


    With such a dependency already in place, that seems like a good idea.

    Terje
    --
    -
    "almost all programming can be viewed as an exercise in caching"

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