I use Trimble Resolution SMT to sync time for a Ubuntu 12.04 server (kernel 3.2.0).
Trimble send NMEA to /dev/ttyUSB1(9600 8N1) on Ubuntu server PPS signal connect ACK pin on /dev/parport0 . Ubuntu load Linux-PPS module( PPS_parport clear_wait=0) to create PPS device /dev/pps0 I use verify the /dev/pps0 using rising edge by "ppstest /dev/pps0" -------------------------------------------------------------------------------------------- trying PPS source "/dev/pps0" found PPS source "/dev/pps0" ok, found 1 source(s), now start fetching data... source 0 - assert 1332775909.500413150, sequence: 249302 - clear 0.000000000, sequence: 0 source 0 - assert 1332775910.500456132, sequence: 249303 - clear 0.000000000, sequence: 0 source 0 - assert 1332775911.500499213, sequence: 249304 - clear 0.000000000, sequence: 0 ----------------------------------------------------------------------------------------------- To verify the NMEA message , I link /dev/ttyUSB1 to /dev/gps1 ----------------------------------------------------------------------------------------------- #cat /dev/gps1 $GPRMC,153343.000,A,4529.904930,N,07343.904831,W,0.241,325,260312,,,A*6F $GPGGA,153344.000,4529.905010,N,07343.904879,W,1,3,3.17,12.368,M,-32.087,M,,*5E --------------------------------------------------------------------------------------------------- I create the /etc/ntp.conf: ------------------------------------------------------------------------- server 127.127.20.1 mode 17 prefer # NMEA RMC/GGA 9600bps fudge 127.127.20.1 time2 0.01 server 127.127.22.0 minpoll 4 maxpoll 4 # PPS ATOM fudge 127.127.22.0 flag2 0 flag3 1 driftfile /var/lib/ntp/ntp.drift ------------------------------------------------------------------------------ after ntpd run 48hours, ntpq -p: remote refid st t when poll reach delay offset jitter ============================================================================== xGPS_NMEA(1) .GPS. 0 l 44 64 377 0.000 -214.54 25.464 xPPS(0) .PPS. 0 l 11 16 377 0.000 -174.60 4.981 I have no idea why I got this result . what do I miss for config? by the way , I compile ntpd from source , not using ntpd from Ubuntu. Thanks for your time to read my question. give me some light please. regards, geng _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
