Re: [ntp:questions] More than one PPS source on Raspberry Pi?
The answer is no and yes (and also maybe).. no because the current pps-gpio driver only loads a single pin (though it could be extended to load more than one, but i dont think anyones done that). yes because the other way it could be achieved is to create a second module called pps-gpio2 and then init that with a different pin config, and that wouldn't be overly hard and possibly easier than trying to extend the existing driver (depending on knowledge of kernel drivers). Lastly, maybe because im unaware of what hardware limits the rpi might have which might get in the way of doing something like that (from what i've read, every pin is capable of being configured for interrupts, so it sounds like it should be possible) On 05/12/17 03:35, Frank Wayne wrote: Has anyone tried to use more than one PPS source at the same time on a Raspberry Pi? The device tree overlay pps-gpio does not seem to support more than one instance. That is, if my config.txt specifies two instances of pps-gpio for different GPIO pins, only /dev/pps0 is created. The documentation for pps_gpio is limited or missing, and the Raspberry Pi forum and the LinuxPPS list have not helped. If pps-gpio cannot do it, is there another way to get PPS devices for Raspbian or another OS that will run on a Pi? Frank Wayne ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Atheros AR9331 w/GPS + PPS
On 8/09/2015 5:44 pm, Gabs Ricalde wrote: On Tue, Sep 1, 2015 at 3:22 AM, Paul J R <m...@pjr.cc> wrote: Hi All, Thought I might share my experiences. Got given a little AR9331 based router some months ago (gl.inet 6416a) and spun up pps on one of its gpio lines. Its been running for about 2 months and so far the performance of it has been quite impressive from a client perspective. Havent seen many references to anyone using an Atheros chipset for pps and ntp so far but im curious if anyone else has had any experiences? Regards, Paul I've been running two devices (TPLink WR703N, MR3020) for more than 2 years with almost no issue. Also impressed on what these devices could do. Does the new OpenWRT versions have the PPS driver for AR9331? I had to use this for Attitude Adjustment: https://code.google.com/p/openwrt-stratum1/ The GL.iNet looks like it's made for hacking, wish it's sold locally. Yeah, i did stumble onto the code on the google, but i ended up writing a new driver myself as that one was polling based. There was a patch (https://github.com/GBert/openwrt-misc/tree/master/gpio-test/src) which adds interrupt based gpio support, so i wrote a patch to add pps-gpio on top of that (https://dl.dropboxusercontent.com/u/49959760/970-pps-gpio-ar9331.patch). Its an openwrt patch specifically for the gl.inet board, but the code is pretty straight forward (though a bit messy) and should work on any ar9331 based box. It'll work on 14.07 and above (though i've only tested compiling it against 14.07 and the current trunk code) I've also tested it with a som9331 openembed board and it seems to work quite well on that as well. Not sure what locally would be for you, but if your in the US, there is a 1-day shipping option (i believe) for that particular box on amazon. To give an idea on size though (which is perhaps what impressed me most), here it is next to an RPI2 https://dl.dropboxusercontent.com/u/49959760/IMG_20150904_014715_w.jpg and im very tempted to make a little waterproof box for it, a poe splitter and stick it to the roof somewhere as the components i've looked at in it all have fairly extreme environment ratings. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] Atheros AR9331 w/GPS + PPS
Hi All, Thought I might share my experiences. Got given a little AR9331 based router some months ago (gl.inet 6416a) and spun up pps on one of its gpio lines. Its been running for about 2 months and so far the performance of it has been quite impressive from a client perspective. Havent seen many references to anyone using an Atheros chipset for pps and ntp so far but im curious if anyone else has had any experiences? Regards, Paul ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp on ubuntu 12.10 with gps and pps.
Im running an intel atom also (old one, d945gclf2 board), and its only doing ntp at the moment with a fairly minimal 64bit ubuntu 12.10 server. after 24 hours its now looking like this: remote refid st t when poll reach delay offset jitter == +203.0.178.191 43.128.117.842 u 38 64 3778.960 -11.714 0.169 *27.54.95.12 218.100.43.702 u 31 64 377 61.301 -1.256 0.246 -202.6.248.7 130.102.128.23 3 u 46 64 3779.529 -0.273 0.160 -116.66.162.4130.234.255.83 2 u 52 64 377 20.386 15.747 1.988 +121.0.0.41 204.152.184.72 2 u 59 64 377 25.295 -4.202 3.760 o127.127.20.0.GPS.0 l18 3770.000 -0.001 0.001 I've just tuned the gps so that its only outputing a single nmea sentence (GPZDA) and increased the speed to 9600 and now its no longer needing the fudge factor. Ultimately though, i'll want to try get it running from a geode based machine (which has some seriously low specs, but it'll be amusing to see how it performs). Something else i've noticed as well when im watching it, when it adjusts the system time it seems to impact the jitter calculation quite considerably and with the other ntp servers in there, it doesnt always seem to want to choose the gps as the absolute truth. On 07/04/13 23:46, David Taylor wrote: On 07/04/2013 11:14, Paul J R wrote: Hi All, I've got a SiRF star 3 GPS with a PPS line which im trying to get running on a machine with ubuntu 12.10 and a serial port using the DCD line for pps signalling. [] o127.127.20.0.GPS.0 l 48 3770.000 -0.065 0.003 [] Seems like a pretty decent little gps unit, assuming i've got it functioning and configured correctly? Just for comparison: Intel Atom PC running FreeBSD 8.2 (Pixie): o127.127.20.1.PPS. offset/jitter -0.001 0.002 Two Raspberry Pis running Linux 3.2.27+ o127.127.22.0.PPS. offset/jitter 0.002 0.002 o127.127.22.0.PPS. offset/jitter 0.001 0.002 Raspberry Pi running Linux 3.36.11 o127.127.22.0.PPS. offset/jitter 0.000 0.002 65 microseconds offset seems a little high to me, but the PCs I've just quoted are all (mostly) /only/ serving NTP. I have been doing a little installation work on Raspberry Pi #3 today, and it now has a steady CPU and network I/O load. Its PPS was only configured yesterday. Performance graphs are here: http://www.satsignal.eu/mrtg/performance_ntp.php I hope that helps your comparisons. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] ntp on ubuntu 12.10 with gps and pps.
Hi All, I've got a SiRF star 3 GPS with a PPS line which im trying to get running on a machine with ubuntu 12.10 and a serial port using the DCD line for pps signalling. Took quite a while as the ntpd that ships with ubuntu 12.10 appears to be compiled without pps support (please correct me if im wrong here - but no matter what I do, the shipped version never tries to open /dev/pps0, gpspps0, etc etc and i've checked permissions and apparmor) - also theres alot of contradictory info on the net about how you get pps and gps operating this way (took some time to find that i needed flag1 1 in the gps settings - which alot of articles dont mention). But, once it was up and running it appeared to work very well, after a few hours the jitter was down to below 0.01. Next I added in a few external time sources, and i ended up with this: remote refid st t when poll reach delay offset jitter == 203.0.178.191 216.218.254.202 2 u 14 6438.704 990.003 0.189 (my isp) 203.82.209.217 18.26.4.105 2 u 18 643 62.372 997.624 0.466 (pool server) 202.127.210.36 223.255.185.22 u 19 643 22.454 1067.75 1.747 (pool server) 130.102.2.123 130.102.132.164 2 u 17 643 22.947 1000.23 0.392 (pool server) 202.125.45.77 223.252.32.9 2 u 17 643 24.810 1001.95 0.849 (pool server) *127.127.20.0.GPS.0 l78 3770.000 0.467 0.209 (GPS) Everythings almost exactly 1 second out. Reading around about this, it appears that this occurs cause theres possibly too many sentences coming across the 4800 baud serial line, is that correct? After adjusting fudge time2, i ended up with with this: remote refid st t when poll reach delay offset jitter == -203.0.178.191 216.218.254.202 2 u 51 64 3779.070 -5.518 1.423 -202.127.210.36 223.255.185.22 u 53 64 377 21.729 74.408 4.701 *203.192.179.99 223.252.32.9 2 u 48 64 377 22.956 17.581 3.551 +119.148.67.183 203.12.160.2 3 u 51 64 377 21.200 4.094 1.439 +203.192.179.98 203.35.83.2422 u 50 64 377 22.735 17.913 27.315 o127.127.20.0.GPS.0 l38 3770.000 5.080 0.193 and a few hours later: remote refid st t when poll reach delay offset jitter == +203.0.178.191 216.218.254.202 2 u 44 64 3779.041 -10.309 0.356 +202.127.210.36 223.255.185.22 u 50 64 377 21.547 64.812 6.039 +203.192.179.99 210.9.192.50 2 u 35 64 377 23.000 -0.256 2.525 -119.148.67.183 203.12.160.2 3 u 48 64 377 21.006 -15.580 4.364 -203.192.179.98 203.35.83.2422 u 49 64 377 23.130 74.392 26.231 o127.127.20.0.GPS.0 l48 3770.000 -0.065 0.003 and the config i've ended up with is: server 127.127.20.0 mode 1 minpoll 2 maxpoll 4 prefer fudge 127.127.20.0 flag1 1 flag2 0 flag3 1 time2 1.0 Seems like a pretty decent little gps unit, assuming i've got it functioning and configured correctly? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] lots of GPS modules and info at SparkFun
Figure I might chime in with the gps unit I got and if your in Aust i think its probably about the best deals i've seen that has a pps line (theres also another one they have if you can do smd soldering thats cheaper again). http://www.twig.com.au/store/product_info.php?products_id=108osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4 http://www.twig.com.au/store/product_info.php?products_id=108osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4 I was looking to put together the dirt-cheapest ntpd machine with pps i could, and that was the cheapest i could find (though i havent had the time to put mine together as yet because the pps line does need some soldering). I also happened to have a wyse terminal (x86 based) http://www.wyse.com/products/hardware/thinclients/S10/index.asp that i picked up for around 30$ (currently running ubuntu 10.10 server without too much drama). On 13/02/12 13:00, Dave Hart wrote: On Sat, Feb 11, 2012 at 10:20, Terje Mathisen wrote: unruh wrote: GEt the manual from Mediatex MTK NMEA Packet User Manual, which gives a far far more extensive set of nmea programming instructions for the chipset that Sure uses. Does that one have more info than my current program? C:\c2\nmea-mtkRelease\nmea-mtk.exe -? nmea-mtk (c) 2011 Terje Mathisen Syntax: nmea-mtk [options] The SURE electronics unit people have been buying as an affordable refclock for those with soldering skills and time is the reference design for the SkyNet SKG16AH chip known as SKG16B [1]. Unruh and Terje are talking about a MTK (I or II?) chipset. Does anyone know the relationship between the two? I'm wondering if there's a way to refer to both unambiguously, or if they're subtly different beasts. After a little more digging I came across a nice comparison table of chipsets [2] which suggests to me the SKG16AH is derived from or clones the interface of a MTk design. If you have additional insight or can correct me, I'd appreciate it. [1] http://www.skylab.com.cn/datasheet/SkyNav_SKG16AH_DS.pdf [2] http://wiki.openstreetmap.org/wiki/GPS_Chipset Cheers, Dave Hart ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
