[ntp:questions] Using Trimble TSIP under Linux
P.Kennedy at fugro.com.au
Mon Oct 29 09:44:21 UTC 2012
ntpd will be in /usr/bin or /usr/sbin. On my pi the /usr/sbin is the
one in use. Just copy across your newly built binary and restart with a
"sudo /etc/init.d/ntp restart"
you can always kill the ntpd process (with a "sudo ps -e | grep ntpd"
followed by "sudo kill -9 <processname>"), then run the one you bult
interactively to make sure all is well. The debug offerings are really
handy in the interactive mode.
From: questions-bounces+p.kennedy=fugro.com.au at lists.ntp.org
[mailto:questions-bounces+p.kennedy=fugro.com.au at lists.ntp.org] On
Behalf Of David Taylor
Sent: Monday, 29 October 2012 5:11 PM
To: questions at lists.ntp.org
Subject: Re: [ntp:questions] Using Trimble TSIP under Linux
On 29/10/2012 08:38, Rob wrote:
> David Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
>> - 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?)
> That is a problem!
> Now I remember...
> I tried different GPS receivers when writing the code for the PPS
> support in gpsd, and there was a receiver for which it would not work
> because the pulse is too narrow for the technique used in gpsd.
> It was the Trimble, I remember now.
> You need to add a circuit to stretch the narrow pulse into a 100ms
> pulse. The exact duration is not important. Just arrange for a
> monostable multivibrator that gets triggered by the rising edge of the
> pulse and extends the pulse by R/C time. Make sure the pulse is
> shorter than 500ms or the autodetection logic will focus on the wrong
> edge of the pulse.
Thanks, Rob. For the moment I have decided to use the pps-gpio code
which has been written for the Raspberry Pi, rather than the gpsd route.
This is producing valid data when running the ppstest (although the
entries of "0" in the clear values worry me slightly), and from the NTP
log I believe that the version I have may not have ATOM support. I've
recompiled NTP, and am thinking about installing it....
I really would prefer not to have to add extra hardware at this point.
questions mailing list
questions at lists.ntp.org
More information about the questions