[ntp:questions] No PPS FreeBSD with NMEA flag1 1 ntpd Ver. 4.2.6p5

Mark C. Stephens marks at non-stop.com.au
Tue Feb 7 01:23:23 UTC 2012

 ntpd - NTP daemon program - Ver. 4.2.6p5

Feb  7 04:37:48 NTP ntpd[1033]: ntpd 4.2.6p5 at 1.2349-o Thu Feb  2 12:33:31 UTC 2012 (1)
Feb  7 04:37:48 NTP ntpd[1033]: logging to file /var/log/ntpd

 7 Feb 04:37:48 ntpd[1034]: c016 06 restart
 7 Feb 04:37:48 ntpd[1034]: c012 02 freq_set kernel 119.790 PPM
 7 Feb 04:37:48 ntpd[1096]: logging to file /var/log/ntpd
 7 Feb 04:37:49 ntpd[1034]: GPS_NMEA(0) 802b 8b clock_event clk_no_reply
 7 Feb 04:37:54 ntpd[1034]: Listen normally on 5 em0 UDP 123
 7 Feb 04:37:54 ntpd[1034]: peers refreshed
 7 Feb 04:37:54 ntpd[1034]: new interface(s) found: waking up resolver
 7 Feb 04:38:01 ntpd[1034]: 8024 84 reachable
 7 Feb 04:38:03 ntpd[1034]: c615 05 clock_sync
 7 Feb 04:38:05 ntpd[1034]: GPS_NMEA(0) 8034 84 reachable
 7 Feb 04:38:53 ntpd[1034]: GPS_NMEA(0) 904a 8a sys_peer

[root at NTP ~]# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
*GPS_NMEA(0)     .GPS.            0 l    1   16  377    0.000   -0.667   0.060
+time.non-stop.c .GPS.            1 u   25   64  377    0.390    5.796   8.888

 [root at NTP ~]# cat /etc/ntp.conf
keys /etc/ntp/keys
trustedkey <removed>
requestkey <removed>
controlkey <removed>

saveconfigdir /etc/ntpd

server mode 24 minpoll 4 maxpoll 4
fudge flag1 1 time2 -0.48

#server minpoll 4 maxpoll 4
#fudge time1 0.525 flag3 1

peer iburst

# others

logconfig =allall
driftfile       /var/db/ntpd.drift
enable stats
statsdir /var/ntp
statistics loopstats peerstats clockstats

[root at NTP ~]# ntpdc -c kerninfo
pll offset:           3.243e-05 s
pll frequency:        106.791 ppm
maximum error:        0.011957 s
estimated error:      8.8e-05 s
status:               2001  pll nano
pll time constant:    4
precision:            1e-09 s
frequency tolerance:  496 ppm
pps frequency:        119.790 ppm
pps stability:        0.000 ppm
pps jitter:           0 s
calibration interval: 4 s
calibration cycles:   0
jitter exceeded:      0
stability exceeded:   0
calibration errors:   0

AFAIK I have done everything exactly as my friend Google said, Any other information that can assist us to track down the issue?

Many thanks,

-----Original Message-----
From: Dave Hart [mailto:hart at ntp.org] 
Sent: Tuesday, 7 February 2012 1:02 AM
To: Mark C. Stephens
Cc: questions at lists.ntp.org
Subject: Re: [ntp:questions] timing issue with a HP 58534A

On Mon, Feb 6, 2012 at 13:50, Mark C. Stephens <marks at non-stop.com.au> wrote:
> This is probably the wrong question to ask, but anyway, I have flag1 1 for refclock 20 in my config.
> Under freebsd how do I verify it is using PPS timestamps?

On any platform, with flag1 1 for the NMEA driver, PPSAPI is attempted.  If it fails, you will see the driver whinge to syslog.  If it succeeds and PPS is working, you'll see 'o' tally code in the first column of ntpq -p output (PPS peer) rather than '*' (system peer).

With flag3 1 (kernel hardpps, that is, kernel sync directly to PPS without ntpd involvement) you can check for PPS indicated in one of several similar outputs:

ntpdc -c kerninfo
ntpq -c kerninfo (requires recent 4.2.7 ntpq and ntpd) ntptime

Dave Hart

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