[ts-7000] GPSD with PPS on COM1 DCD

["jywmpg" <>]

Has anyone got GPSD running using the PPS (Pulse Per Second) signal to
synchronize NTP?

I have a Garmin 18LVC connected to COM1 on a 7260, with the PPS line
connected to the DCD pin of COM1.   Using a scope, I can tell that the
Garmin is supplying a 100 ms pulse to DCD once a second.

GPSD is supposed to detect the transitions on DCD and use that
information to provide a clock to NTP, via shared memory.

Unfortunately, running GPSD at a high debug level shows no indication
that GPSD sees the PPS transitions on DCD.  If the transitions are
detected, debug messages should be generated

I have removed /dev/ttyAM0 from /etc/inittab, and redirected the
console output to COM2 via JP4 and JP2.

I have downloaded the GPSD 2.34 and built from scratch, making sure
that both SHM and PPS are enabled, and that PPS is input on DCD.

GPSD is capable of producing both a low resolution clock (derived fro
m characters arriving on the serial line) and a high resolution clock
(derived from the PPS signal).  The low precision clock works, but the
high precision one does not.

This is demonstrated in the following:

# ntpq -p
     remote           refid      st t when poll reach   delay   offset
 jitter
==============================================================================
*SHM(0)          .GPSa.           0 l    7   16  377    0.000  -198.66
 37.583
 SHM(1)          .PPSa.           0 l    -   16    0    0.000    0.000
  0.061
 tss1            .STEP.          16 u    -   64    0    0.000    0.000
  0.000
 tss6            .STEP.          16 u    -   64    0    0.000    0.000
  0.000
 LOCAL(0)        .LOCL.          10 l    8   64  377    0.000    0.000
  0.061


Questions:

1. Does anyone have this setup working?
2. Is there some other way to monitor the DCD line to see if it is
actually getting into the 7260?

Any suggestions would be appreciated.


jw





 
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