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Re: [ts-7000] GPSD with PPS on COM1 DCD

To:
Subject: Re: [ts-7000] GPSD with PPS on COM1 DCD
From:
Date: Fri, 3 Aug 2007 21:08:06 -0500
Don't know anything about GPSD, did you try removing ttyAM0 from the  
kernal msgs?

Then Kernal msgs need to be changed.  So in redboot edit the script  
via fconfig, have it point to ttyAM1 instead of ttyAM0: exec -c  
"console=ttyAM1 ..."

Just an idea, helped me on a device I was working on.



Quoting 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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