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by Paul Kennedy
Tue Aug 28, 2012 9:54 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Good. It looks like it is now taking hold of the ZDA. You are really close. I need to think why on earth it is not happy. Maybe remove the fudge 0.400?
by Paul Kennedy
Tue Aug 28, 2012 9:33 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, my bad. I gave the the incorrect bit field. This snippet is from our standard conf file... ####RS232 BASED REFERENCE CLOCKS#################################### #The mode field is a bitwise value which is the combination of DATAGRAM+BAUD #e.g. if you have a DATAGRAM=ZDA, BAUD=38400 the mode is 8+...
by Paul Kennedy
Tue Aug 28, 2012 1:19 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, thanks for the debug dump. This helps. I can see your GPS is talking multiple sentences. At present, I see GGA, GSV, ZDA, PGTOP being output. I believe the NMEA clock driver only holds the current sentence in memory. As you have not told NTP to decode any specific message, it is probably rotatin...
by Paul Kennedy
Mon Aug 27, 2012 4:04 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

btw what version of ntp are you running? i saw some chatter about a custom build above. looks like you are getting close now. i would have thought it would have kicked in by now, so something must be up. i would keep the polling fast. there are a couple more things to chase down if it does not settl...
by Paul Kennedy
Mon Aug 27, 2012 3:55 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

ok, this is progress. now lets speed it all up. as you have a local clock source, you can poll quicker than 64 secs. on my boxes we poll at a solid 8 secs. do this with minpoll and maxpoll (it is a pwr 2 thing). also set iburst, which polls quickly at startup and settles things faster i remember som...
by Paul Kennedy
Mon Aug 27, 2012 2:40 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, this x86 box looks very much like it is using the shared mem driver not the kernel disciplined PPS. GPSD is taking in both the NMEA and PPS pulse from pin1, and populating the shared memory segment. NTP picks them up as sources. you need to specify the prefer keyword to the 127.127.28.1 so NTP k...
by Paul Kennedy
Mon Aug 27, 2012 1:09 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, I think I can see your issue. PPS provides a nice pulse, but it does NOT provide the actual time. NTP needs to get that from elsewhere (ie another refclock). you control this with the 'prefer' keyword. ie server 127.127.20.0 mode 16 prefer fudge 127.127.20.0 flag1 1 time2 0.400 server 127.127.22...
by Paul Kennedy
Sun Aug 26, 2012 3:37 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

any chance you can outline the model of the GPS from sparkfun? I saw the entry for the sure electronics board, but it does not appear to be a positing from yourself, so I am a little confused right now. many thanks I'm not sure who you are addressing as several people have posted to this thread... ...
by Paul Kennedy
Sun Aug 26, 2012 12:24 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

oops, my isp just changed the IP to http://120.145.202.235
I just tested this and it is working fine. I also enabled port 123, and tested this from a different box.
I need to get with my isp and get a static IP (US$10 extra per month!)
by Paul Kennedy
Sun Aug 26, 2012 9:34 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi Aquarat, NTP often gets a little narky if multiple ref clocks with similar stratums suggest vastly different times (vast means 10s of millisecs). It simply does not know who to believe, especially if the delay to your local ref clocks (pps and NMEA) are extremely low. NMEA is always a troublesome...
by Paul Kennedy
Sat Aug 25, 2012 4:59 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, I have just popped my pi on the web. I do not yet have a GPS, but it is on the way. I already made a small website to expose some internals such as offset, freq and CPU load, and a realtime plot to boot. http://121.221.94.250/ At present, I only have internet ref clocks, so less than ideal, but ...
by Paul Kennedy
Sat Aug 11, 2012 3:27 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi
any chance you can outline the model of the GPS from sparkfun? I saw the entry for the sure electronics board, but it does not appear to be a positing from yourself, so I am a little confused right now. many thanks
by Paul Kennedy
Tue Aug 07, 2012 12:16 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 136927

Re: NTP PPS

Hi, A very interesting project. Well done. I had a look at Spark fun, but it was not clear which GPS unit you are hooking up to the Pi. Coule you please let me know so I get the same unit?

many thanks

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