[ntp:questions] Using Trimble TSIP under Linux

A C agcarver+ntp at acarver.net
Sun Oct 28 20:53:36 UTC 2012

On 10/28/2012 13:50, A C wrote:
> On 10/28/2012 13:31, David Taylor wrote:
>> On 28/10/2012 16:50, Rob wrote:
>> []
>>> Sorry I have no idea how to get it to work with a raspberry pi.
>>> I think when you have to tinker with drivers anyway, it is better
>>> to adapt a driver from ntpd and leave out gpsd.
>>> (unless you want to use the positioning information from the receiver
>>> for a local app that supports gpsd)
>> Rob,
>> Thanks for your comments.  I don't /need/ gpsd, but it does seem to be
>> at least partially working.  I've made progress by looking at the
>> various Internet sources, and found someone who had recompiled my
>> version of Linux to include PPS support.  So now I can:
>> - use cgps -s to see the output from the GPS via gpsd
>> - configure NTP to use the type 28 driver and it sees the GPS time
>> - use sudo ppstest /dev/pps0 and see assert pulses coming in
>>    (the clear field is always 0 though, perhaps the 150
>>     microsecond pulse is too narrow?)

Also, you may need to investigate adding a pulse stretcher to the PPS 
signal if ppstest is having trouble with some of the pulses.  The pulse 
should be in the tens to hundreds of milliseconds in length to make sure 
the system recognizes it.  It may work as is, won't hurt to try but you 
may still have some hardware to add.

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