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Old 10-21-2007, 11:01 AM   #1
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Registered: Oct 2007
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NTP driver not taking PPS

I am using
Kernel :2.6.23rc2
PPS patch: ntp -pps-2.6.23rc2.diff
NTP version: ntp-4.2.4P4

I have enabled PPS support as a module.Under this I have selected PPS debugging message,UART serial support.

I am using GPS Receiver TRIMBLE ACE 3 .
PPS from GPS receiver is fed to MAX232 and output of MAX232 is fed to DCD pin of serial port.The serial port I have used is ttys3.

The relevant part of my ntp.conf is


enable stats

statsdir /var/log

statics loopstats

logconfig = all
server mode 138 prefer iburst
fudge refid TSIP flag3 1 flag2 0 time1 0.042


fudge stratum 10


These are the results after about half an hour:


ntpq -p

remote refid st t when poll reach delay offset jitter
xGENERIC(3) .TSIP. 0 1 39 64 377 0.000 -35.67 35.234

LOCAL(0) LOCAL(0) 1 20 64 377 0.000 0.000 0.004



ntp_gettime() returns code 0 (OK)
time CAC57B62.7EC56000,SUN, Oct 21 2007 12:56:43.265, (.265534),
maximum error 1061671us, estimated error 2us
ntp_adjtime() returns code 0 (OK)
modes 0x0 (),
offset 0.000 us, frequency -0.000 ppm, interval 1 s,
maximum error 1121063 us, estimated error 2 us,
status 0x1 (PLL),
time constant 6, precision 1.000 us, tolerance 512 ppm,


Information for generic driver is coming in log file.But no info regarding PPS is coming in log file.

But if I am runing the ppstest file I can see PPS data.

What could be the possible reason for PPS not being used?

Please feel free to ask if any more details is required...


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