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From: | Benedikt Kleinmeier |
Subject: | [gpsd-users] PPS Problem with U-blox NEO-7 GPS Under Debian 7.5 (Wheezy) |
Date: | Wed, 21 May 2014 09:59:04 +0200 |
Hi, I try to synchronize time of different computers in a Car2X scenario. I configured gpsd and nptd successfully using the official HOWTO (http://www.catb.org/gpsd/gpsd-time-service-howto.html): address@hidden:~# ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== … *SHM(0) .GPS. 0 l 39 64 377 0.000 -24.724 19.001 SHM(1) .PPS. 0 l - 64 0 0.000 0.000 0.000 I also configured ntpd to use the PPS signal, but gpsd doesn’t process the PPS signal provided by the u-blox NEO-7 GPS (see above: “reach” is 0). I’m not sure if it is a hardware or software problem. I use a slightly modified Intel Atom board. From the manual: “[…] to get exact time informations a CPLD from Lattice is connect to the timepuls pin of the NEO-7. The CPLD is connected to the computer board using the LPC bus.” Linux recognizes a PPS device (dmesg | tail): … [ 36.215407] pps_core: LinuxPPS API ver. 1 registered [ 36.215415] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <address@hidden> [ 36.217828] pps_ldisc: PPS line discipline registered [ 36.218396] pps pps0: new PPS source acm0 [ 36.218417] pps pps0: source "/dev/ttyACM0" added But using the PPS signal fails: address@hidden:~# ppstest /dev/pps0 trying PPS source "/dev/pps0" found PPS source "/dev/pps0" ok, found 1 source(s), now start fetching data... time_pps_fetch() error -1 (Connection timed out) … Running gpsd in foreground reports an error (gpsd –n –N –D 4 /dev/ttyACM0): … gpsd:INFO: KPPS checking /sys/devices/virtual/pps/pps0/path, /dev/ttyACM0 gpsd:INFO: KPPS caps 1133 gpsd:WARN: KPPS kernel PPS will be used gpsd:ERROR: PPS ioctl(TIOCMIWAIT) failed: 22 Invalid argument gpsd:PROG: PPS gpsd_ppsmonitor exited??? Maybe someone has a clue how to narrow down the problem Thank you, Benedikt |
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