On Thursday, 6 February 2014 16:35:15 UTC+5:30, Charles Elliott wrote: > The config file should have this format > > > > server 127.127.20.1 mode 65 minpoll 4 maxpoll 4 prefer > > fudge 127.127.20.1 time2 0.363352 > > fudge 127.127.20.1 flag4 0
Hi Charles Elliott, i have corrected mode 0 to mode 1 as i am using only NMEA output of gps receiver at 4800 baudrate. > > > > > > Charles Elliott > > -----Original Message----- > > From: questions-bounces+elliott.ch=verizon....@lists.ntp.org > > [mailto:questions-bounces+elliott.ch=verizon....@lists.ntp.org] On Behalf Of > > rajputaja...@gmail.com > > Sent: Thursday, February 6, 2014 4:58 AM > > To: questions@lists.ntp.org > > Subject: Re: NTP NMEA driver > > > > Dear Sir, > > > > I am trying to synchronize AM335x processor based linux 3.2 with Motorola > > GPS receiver using its Serial based NMEA frame and 1pps signal. I have > > connected nmea frame to ttyO1 port. I am using buildroot based filesystem > > for NTP configuration. NTP version used is 4.2.6p5. > > > > I have configured ntp.conf file for nmea driver 20 for nmea and 1pps > > options. (refer: > > http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver20.html) > > > > # Ajay - for nmea driver 20 > > server 127.127.20.0 mode 0 minpoll 4 maxpoll 4 prefer fudge 127.127.20.0 > > flag1 1 flag2 0 flag3 1 time2 0.500. > > > > time2 is set to 0.600 since delay between 1pps signal rising edge and end of > > nmea frame is approx 500ms. > > > > i am issuing below command for nmea driver 20 before starting ntp service: > > > > ldattach pps /dev/ttyO1. > > > > [ 94.658905] pps_core: source OMAP-SERIAL1 got cdev (253:0) > > [ 94.658935] pps pps0: new PPS source OMAP-SERIAL1 > > [ 94.663787] pps pps0: source "/dev/ttyO1" added > > > > > > > > Also, while kernel booted it already had registered pps for kernel line > > discopline as per below message: > > [ 0.181427] pps_core: LinuxPPS API ver. 1 registered > > [ 0.181427] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo > > Giometti <giome...@linux.it> > > > > > > ln -s /dev/ttyO1 /dev/gps0 (for linking ttyO1 to /dev/gps0 for nmea driver > > 20) (as per http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver20.html) > > and > > ln -s /dev/pps0 /dev/gpspps0 (for linking pps0 to /dev/gpspps0 for nmea > > driver 20) (as per > > http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver20.html) > > > > Now, when i start the ntp service, i get below output for ntpq -p command: > > > > > > remote refid st t when poll reach delay offset > > jitter > > ============================================================================ > > == > > *GPS_NMEA(0) .GPS. 0 l 4 16 377 0.000 4526.86 > > 1269.17 > > > > Problem: Though i have configured my ntp.conf file for nmea and 1pps both > > (using flag1 1), i do not see any entry for PPS in ntpq -p command. > > if kernel has registered pps0 as pps source, why there is not PPS entry. I > > have connected pps signal of 3.3v level to my dcd pin of ttyO1. > > > > Also, the offset in NMEA output continously increases insteed of reducing. > > > > Thanks & Regards, > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
