Re: anyone have any nmea(4) stories?
On 10/7/06, Henning Brauer [EMAIL PROTECTED] wrote: inserts USB GPS device uplcom0 at uhub1 port 4 uplcom0: Prolific Technology PL2303 Serial, rev 1.10/2.02, addr 4 ucom0 at uplcom0 # nmeaattach cuaU0 # sysctl hw.sensors.30 hw.sensors.30=nmea0, GPS, 0.77 secs, OK, Fri Oct 6 21:23:53.453 # echo 'sensor nmea0' /etc/ntpd.conf # date Fri Oct 6 21:29:29 EDT 2006 # date 35 Fri Oct 6 21:35:00 EDT 2006 # sysctl hw.sensors.30 hw.sensors.30=nmea0, GPS, 281.16 secs, OK, Fri Oct 6 21:35:28.815 # ntpd -ds ntp engine ready sensor nmea0 added sensor nmea0: offset -280.827497 no reply received in time, skipping initial time setting sensor nmea0: offset -280.817099 sensor nmea0: offset -280.817388 sensor nmea0: offset -280.841698 sensor nmea0: offset -280.843981 sensor nmea0: offset -280.829276 sensor nmea0: offset -280.840579 snip This goes on forever and the time is never actually adjusted according to the timedelta. The timedelta seems to be working quite well, but ntpd isn't adjusting according to it. What am I doing wrong? you never get a adjusting local clock by ... message?!? Correct. I just keep getting this message forever: sensor nmea0: offset -280.800595. My ntpd.conf has no servers defined in it it only has this one sensor. I ran it for a few hours and it never adjusted my time at all (no messages in /var/log/daemon either about it adjusting either. I'm running a box a week or so away from -current and it doesn't seem like any of that code has been touched in a while. # uname -a [EMAIL PROTECTED]:6$ uname -a OpenBSD pi.local 4.0 GENERIC#3 i386 Any ideas...? -Sam
Re: anyone have any nmea(4) stories?
On 10/7/06, Chris Kuethe [EMAIL PROTECTED] wrote: usb gps receivers don't usually have any sort of PPS signal which is what this code depends on. CK As I understand it, ntpd uses a timedelta sensor to make adjustments to the clock. If nmeaattach properly creates a timedelta sensor (and it does because I have one that properly shows my offset) then this should work. ntpd doesn't know anything about my gps receiver it only knows that there is a timedelta sensor on my computer. That's at least how I understand it. -Sam
Re: anyone have any nmea(4) stories?
On 10/7/06, Chris Kuethe [EMAIL PROTECTED] wrote: usb gps receivers don't usually have any sort of PPS signal which is what this code depends on. CK As I understand it, ntpd uses a timedelta sensor to make adjustments to the clock. If nmeaattach properly creates a timedelta sensor (and it does because I have one that properly shows my offset) then this should work. ntpd doesn't know anything about my gps receiver it only knows that there is a timedelta sensor on my computer. That's at least how I understand it. That is correct. You plug a GPS receiver into a serial port, or into a USB port which makes it come up as a serial port. But it is just some random device on a serial port. We don't know that there is a GPS on that particular serial port. But you do -- so you run the nmeaattach, indicating the serial port that the GPS is on. nmeaattach tells the kernel to 'intercept' the data on that particular serial port. If the kernel code notices that the little bytes flowing by look like the GPS NMEA protocol, then the kernel creates a timedelta sensor. Every once in a while, ntpd checks to see if any new timedelta sensors have showed up (or, likewise, if any have gone away). And ntpd uses their value as an offset against true time.
anyone have any nmea(4) stories?
Has anyone set up a GPS to serve as a ntp source yet? Care to share any insights gained? Thanks. j
Re: anyone have any nmea(4) stories?
On 10/6/06, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Has anyone set up a GPS to serve as a ntp source yet? Care to share any insights gained? Thanks. j inserts USB GPS device uplcom0 at uhub1 port 4 uplcom0: Prolific Technology PL2303 Serial, rev 1.10/2.02, addr 4 ucom0 at uplcom0 # nmeaattach cuaU0 # sysctl hw.sensors.30 hw.sensors.30=nmea0, GPS, 0.77 secs, OK, Fri Oct 6 21:23:53.453 # echo 'sensor nmea0' /etc/ntpd.conf # date Fri Oct 6 21:29:29 EDT 2006 # date 35 Fri Oct 6 21:35:00 EDT 2006 # sysctl hw.sensors.30 hw.sensors.30=nmea0, GPS, 281.16 secs, OK, Fri Oct 6 21:35:28.815 # ntpd -ds ntp engine ready sensor nmea0 added sensor nmea0: offset -280.827497 no reply received in time, skipping initial time setting sensor nmea0: offset -280.817099 sensor nmea0: offset -280.817388 sensor nmea0: offset -280.841698 sensor nmea0: offset -280.843981 sensor nmea0: offset -280.829276 sensor nmea0: offset -280.840579 snip This goes on forever and the time is never actually adjusted according to the timedelta. The timedelta seems to be working quite well, but ntpd isn't adjusting according to it. What am I doing wrong? I think it would be very useful to make a note about nmeaattach(8) in nmea(4) I almost couldn't find the darn thing. Index: nmea.4 === RCS file: /cvs/src/share/man/man4/nmea.4,v retrieving revision 1.9 diff -u -r1.9 nmea.4 --- nmea.4 3 Sep 2006 18:26:05 - 1.9 +++ nmea.4 7 Oct 2006 01:22:36 - @@ -67,6 +67,7 @@ .El .Sh SEE ALSO .Xr tty 4 , +.Xr nmeaattach 8 , .Xr ntpd 8 , .Xr sysctl 8 .Sh HISTORY -Sam
