[time-nuts] Getting ntpd to work with Garmin LVC-18x and Ubuntu 16.04..

Howard Leadmon howard at leadmon.net
Sat Jul 16 14:43:52 EDT 2016

  I have been running my Garmin under FreeBSD for a few years, and it's been
working great.   So I recently had to shift to Ubuntu Linux 16.04, and
honestly thought it would be easy to plug everything in and just make it
happy.   Reading the various docs for Ubuntu 16.04 LTS, it says all of the
modules are built and loaded, and an lsmod shows this is the case.


# lsmod|grep pps

pps_ldisc              16384  1

pps_core               20480  1 pps_ldisc


So it looks ready to roll.   I then hooked up the garmin, I use the serial
line for pps, and power it from a USB port, and figured it would probably
sync up, but no such love. I have tried using the NEMA driver, enabling PPS,
and I even tried using the NEMA driver with the PPS driver (.22) added in as
well, but no love.


The ntptime command just never shows anything to do with pps:


ntp_gettime() returns code 0 (OK)

  time db34fdf6.b3f1c758  Sat, Jul 16 2016 14:39:50.702, (.702908970),

  maximum error 464140 us, estimated error 17306 us, TAI offset 0

ntp_adjtime() returns code 0 (OK)

  modes 0x0 (),

  offset 53253.096 us, frequency -6.870 ppm, interval 1 s,

  maximum error 464140 us, estimated error 17306 us,

  status 0x2001 (PLL,NANO),

  time constant 9, precision 0.001 us, tolerance 500 ppm,



Here is my current configuration, and I have even tried various iterations
as you will see from the stuff commented out:


# Try and get GPS/USB Time Going


#server mode 1 prefer

#fudge flag1 1 flag2 0 flag3 1 time2 0.800


#server mode 0 minpoll 4 maxpoll 4 prefer

#fudge flag1 1 flag2 0 flag3 1 time2 0.600


server mode 16 minpoll 3 prefer

fudge flag1 1 flag2 1 flag3 1 time1 0.0


#server                    # ATOM(PPS)

#fudge flag3 1             # enable PPS module

#pps /dev/pps0 assert hardpps



Does anyone have any ideas, or have this all working under Ubuntu 16.04 LTS?
I would sure love to get my time server back online, as I pretty much have
everything on the network sync with it..




Howard Leadmon 


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