[ntp:questions] Getting PPS to work with Oncore ref clock

David Lord snews at lordynet.org
Thu Feb 17 08:54:10 UTC 2011


Hal Murray wrote:
> In article <AANLkTikErZ-bkbwnFBQHWsNe7OUL=Sx4oeTg+9R_ujd6 at mail.gmail.com>,
>  Chris Albertson <albertson.chris at gmail.com> writes:
>> I have to admit I know nothing abut Linux serial PPS.   My guess is I
>> need to somehow set this up before I try to get it to work with NTP.
>> My clockstats file is filled with the the messages quoted below.   Is
>> there something I can read.   I've build ntpd with the required pps
>> support, have the "correct" Linux kernel and header files, made links
>> in /dev.  Hard to know what's missing.  The error messages are not
>> very helpful
>>
>> 55609 21559.296 127.127.30.0 ONCORE[0]: ONCORE: oncore_get_timestamp,
>> error serial pps
>> 55609 21589.292 127.127.30.0 ONCORE[0]: ONCORE: oncore_get_timestamp,
>> error serial pps
>> 55609 21619.312 127.127.30.0 ONCORE[0]: ONCORE: oncore_get_timestamp,
>> error serial pps
> 
> For things like this, your best bet is to look at the source code.
> 
> Usually greping for the text in the error message won't get very
> many hits.
> 
> I took a quick look.  I think it's trying to tell you that it's not
> getting a PPS pulse.
> 
> Do you have a scope?  Is the hardware making PPS pulses?  How wide are
> they? ...

or even a LED + diode + resistor will be enough to show if there is
a pulse. Radioclkd2 can be used in debug mode to confirm the single
DCD pulse and width.

David




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