[ntp:questions] NMEA driver using common PPSAPI code

Venu Gopal neo.venu at gmail.com
Tue Oct 26 08:37:07 UTC 2010


Hello Dave,

Following are few observations with NMEA driver using common PPSAPI:

1. flag1 0, flag2 0, flag3 0, time1 0 and time2 0 : Normal behavior
2. flag1 1, flag2 0, flag3 0, time1 0 and time2 0: Clock is stepped on
startup and on clock_sync event
3. flag1 1, flag2 0, flag3 1, time1 0 and time2 0: Clock is stepped on
startup and on clock_sync event
4. flag1 1, flag2 0, flag3 0, time1 0 and time2 x: Clock doesn't step
(Normal behavior)
5. flag1 1, flag2 0, flag3 1, time1 0 and time2 x: Clock doesn't step
(Normal behavior)

I've tested with uBlox GPS receiver (which of course doesn't spit ZDG
sentences).
The moment I use Accord's GPS Clock, which generates ZDG, the clock steps
randomly
sometimes from few milli-seconds to 14.5 seconds. The biggest problem here
is that the step
size if not constant :-).

Any clues of why this is happening?
If someone can hint me how to debug, I can check with the existing setup.
Somehow
this never happened with the older version.

Regards,
Venu



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