[ntp:questions] ntp.conf file setup in netbsd

Runa Dahal anur55 at gmail.com
Fri Jul 10 15:46:27 UTC 2009


I am using NetBSD 5.0 operating system in a low powered embedded computer
used solely for the purpose of NTP. I have enabled options PPS_SYNC option
in the kernel and rebuilt it. My ntp.conf file has the following set up:

server 127.127.20.1

fudge 127.127.20.1 flag3 1 refid NMEA

server 127.127.22.1

fudge 127.127.22.1 refid PPS


 I am using com2 to receive data throught the serial sevice. I have also
created symbolic links as follow to point to the serial device.


 ln -s /dev/tty01 /dev/gps1

ln -s /dev/tty01 /dev/pps1


 I have also tried using flag1 1 to enable the PPSAPI as fudge 127.127.20.1
flag1 1 flag3 1 refid NMEA


 But still my ntp machine is not synchronizing , the delay, offset , jitter
values are still zero. When I run the minicom i am still able to receive
GPZDA string . I know the NMEA/PPS signals are working, because I already
have the GPS connected to a machine running fedora core 4, using gpsd to
populate NMEA and PPS values to shared memory. I have this new low power
system, and would like to move away from gpsd to maximize accuracy. So, I
know the hardware is working, and that the problem is all
software/configuration issues.I have read about using ntpd with PPS signal,
and that NetBSD does not require any patching, just recompiling kernel with
PPS_SYNC to enable kernel PPS discipline. I have see several examples
online, and I do not seem to be missing anything, and yet my system still
refuses to work. I am looking for guidance on this issue.

When i ran the ntpd in debug mode my output was as follows

addto_syslog: Listening on interface #0 wildcard, 0.0.0.0#123 Disabled

addto_syslog: Listening on interface #1 wildcard, ::#123 Disabled

addto_syslog: Listening on interface #2 re0, 192.168.0.15#123 Enabled

addto_syslog: Listening on interface #3 re0, fe80::260:e0ff:fe46:c1f1#123
Enabled

addto_syslog: Listening on interface #4 lo0, 127.0.0.1#123 Enabled

addto_syslog: Listening on interface #5 lo0, ::1#123 Enabled

addto_syslog: Listening on interface #6 lo0, fe80::1#123 Enabled

addto_syslog: Listening on routing socket on fd #27 for interface updates

local_clock: time 0 offset 0.000000 freq 0.000 state 0

addto_syslog: kernel time sync status
0x2140<UNSYNC,PPSSIGNAL,NANO,MODE=0x0=PLL,CLK=0x0=A>

peer_crypto_clear: at 0 next 0 assoc ID 49312

key_expire: at 0

peer_clear: at 0 next 1 assoc ID 49312 refid INIT

refclock_setup fd 5 modem status: 0x7

refclock_ioctl: fd 5 flags 0x1

refclock_ppsapi: capability 0x1033 version 1 mode 0x1001 kern 0

newpeer: 127.0.0.1->127.127.20.1 mode 3 vers 4 poll 6 10 flags 0x1021 0x1
ttl 0 key 00000000

refclock_ppsapi: capability 0x1033 version 1 mode 0x1001 kern 4

peer_crypto_clear: at 0 next 0 assoc ID 49313

key_expire: at 0

peer_clear: at 0 next 2 assoc ID 49313 refid INIT

refclock_ppsapi: fd 6 capability 0x1033 version 1 mode 0x1001

newpeer: 127.0.0.1->127.127.22.0 mode 3 vers 4 poll 6 10 flags 0x1021 0x1
ttl 0 key 00000000

refclock_ppsapi: fd 6 capability 0x1033 version 1 mode 0x1001

addto_syslog: frequency initialized 20.291 PPM from /var/db/ntpd.drift

local_clock: time 0 offset 0.000000 freq 20.291 state 1

report_event: system event 'event_restart' (0x01) status 'sync_alarm,
sync_unspec, 1 event, event_unspec' (0xc010)

nmea: gpsread 33 $GPZDA,211347.000,09,07,2009,,*51

refclock_transmit: at 1 127.127.20.1

auth_agekeys: at 1 keys 1 expired 0

timer: refresh ts 0

timer: interface update

nmea: gpsread 33 $GPZDA,211348.000,09,07,2009,,*5E

refclock_transmit: at 2 127.127.22.0

peer PPS(0) event 'event_peer_clock' (0x85) status 'unreach, conf, 1 event,
event_peer_clock' (0x8015)

nmea: gpsread 33 $GPZDA,211349.000,09,07,2009,,*5F

nmea: gpsread 33 $GPZDA,211350.000,09,07,2009,,*57

nmea: gpsread 33 $GPZDA,211351.000,09,07,2009,,*56


I have a couple questions regarding NMEA PPS. If I am using kernel PPS
discipline, then do I not need to specify ntpd atom pps(22) driver? I know I
need to have flag3 1 flag. Can I use ntpd PPS driver instead of kernel PPS
even with NetBSD being compiled PPS_SYNC, so, that I could easily switch
being either for testing. Do I always need to specify flag1 1 since I need
PPS ?

It would be very helpful if anyone could suggest possible reasons for this.
Thank you.

Runa



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