[ntp:questions] Using PPS

Joshua Small JSmall at daraco.com.au
Fri Dec 28 00:15:01 UTC 2012


Hi David,

Thank you for this. I guess this leads me to the question of "how do I debug this", since I seem to have neither of those features listed.

I do note that your example uses the ATOM driver 22, whereas several pages have referred me to using the driver 20 as a "better" option - was this a bad move?

I did have to compile my own kernel as I added other modules not present in the precompiled kernels featuring the PPS

pi at raspberrypi ~ $ ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*GPS_NMEA(0)     .GPS.            0 l    4    8    1    0.000  -27.038   0.004
+wombat.osoal.or .GPS.            1 u    1   64    1   43.639  144.936   1.213
 warrane.connect 130.95.179.80    2 u    1   64    1    5.842  144.114   0.574
+203.192.179.98  223.252.32.9     2 u    2   64    1   21.483  103.720   1.765

pi at raspberrypi ~ $ ntpq -c rv

associd=0 status=0415 leap_none, sync_uhf_radio, 1 event, clock_sync,
version="ntpd 4.2.7p334 at 1.2483-o Mon Dec 17 22:19:03 UTC 2012 (1)",
processor="armv6l", system="Linux/3.2.27+", leap=00, stratum=1,
precision=-18, rootdelay=0.000, rootdisp=1028.296, refid=GPS,
reftime=d4875ebc.1c973e69  Fri, Dec 28 2012 10:56:44.111,
clock=d4875ebd.51aa5e49  Fri, Dec 28 2012 10:56:45.319, peer=1115, tc=3,
mintc=3, offset=-36.735257, frequency=-14.904, sys_jitter=47.867458,
clk_jitter=58.208, clk_wander=0.000

(the somewhat large offset is due to the fact I only turned this on two seconds before running the command.. they do level out)

I'm running dev version 4.2.7p334, I also tried stable 4.2.6p5 with no difference.




-----Original Message-----
From: questions-bounces+jsmall=daraco.com.au at lists.ntp.org [mailto:questions-bounces+jsmall=daraco.com.au at lists.ntp.org] On Behalf Of David Taylor
Sent: Friday, 28 December 2012 1:37 AM
To: questions at lists.ntp.org
Subject: Re: [ntp:questions] Using PPS

On 27/12/2012 10:55, Joshua Small wrote:
Josh,

My own notes on the Raspberry Pi are here:

   http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#pps

I hope there is some useful diagnostic information there.  You should a "o" against the PPS source in the "ntpq -p" output, and a "kern" entry in the "ntpq -c rv" output.

Here are the results from my Raspberry Pi:

C:\Users\David>ntpq -c rv 192.168.0.14
associd=0 status=011d leap_none, sync_pps, 1 event, kern, version="ntpd 4.2.7p329 at 1.2483 Sun Dec  2 09:10:46 UTC 2012 (1)", processor="armv6l", system="Linux/3.2.27-pps-g965b922-dirty", leap=00, stratum=1, precision=-19, rootdelay=0.000, rootdisp=1.135, refid=PPS, reftime=d486da8e.004dd4ef  Thu, Dec 27 2012 14:32:46.001, clock=d486da97.0dff9b5b  Thu, Dec 27 2012 14:32:55.054, peer=2679, tc=4, mintc=3, offset=0.001799, frequency=-41.199, sys_jitter=0.002386, clk_jitter=0.000, clk_wander=0.000

C:\Users\David>ntpq -p 192.168.0.14
      remote           refid      st t when poll reach   delay   offset 
  jitter
==============================================================================
oPPS(0)          .PPS.            0 l    8   16  377    0.000    0.002 
  0.002
*pixie           .PPS.            1 u   14   32  377    0.511   -0.012 
  0.031
+FEENIX          .PPS.            1 u   17   32  377    0.605    0.028 
  0.028
+Stamsund        .PPS.            1 u    6   32  377    0.601   -0.039 
  0.135
  uk.pool.ntp.org .POOL.          16 p    - 1024    0    0.000    0.000 
   0.002
-time.mhd.uk.as4 213.229.82.130   3 u  396 1024  377   24.654   13.474 
  5.664
-dawn.rt.uk.eu.o 193.79.237.14    2 u 1066 1024  377   19.163    2.598 
  3.815
-cadmium.cloudfa 195.66.241.2     2 u  103 1024  377   26.394    2.699 
  3.609
-time.dan.me.uk  82.148.230.254   2 u  787 1024  377   17.598    0.409 
  3.568
--
Cheers,
David
Web: http://www.satsignal.eu

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