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?)
but NTP never connects to the PPS source. My NTP configuration looks like:
If your PPS signal is on /dev/pps0 as you describe, add the ATOM driver
(number 22) in addition to your SHM (gpsd) driver and it will be fine:
This is exactly how I have my own server running (but not on an R-pi).
PPS comes in via one port, gpsd SHM comes in from another port and two
drivers (22 and 28) take care of gluing them together.
===========================================
driftfile /var/lib/ntp/ntp.drift
server 127.127.28.0 minpoll 4 maxpoll 4
fudge 127.127.28.0 time1 +0.350 refid GPS stratum 15
server 127.127.22.0 minpoll 4 maxpoll 4
server 127.127.28.1 minpoll 4 maxpoll 4 prefer
fudge 127.127.28.1 refid PPS
server 192.168.0.3 minpoll 5 maxpoll 5 iburst prefer
server 192.168.0.2 minpoll 5 maxpoll 5 iburst
server 192.168.0.7 minpoll 5 maxpoll 5 iburst
pool uk.pool.ntp.org minpoll 10 iburst
===========================================
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