[ntp:questions] Getting PPS to work with Oncore ref clock

Mike S mikes at flatsurface.com
Thu Feb 17 12:40:09 UTC 2011


At 01:16 AM 2/17/2011, Chris Albertson wrote...
>  My guess is I
>need to somehow set this up before I try to get it to work with NTP.

Yes, NTP messages aren't very informative. Do you have the 
pps-tools(ppstest specifically)? Info at 
http://wiki.enneenne.com/index.php/LinuxPPS_installation#The_userland_tools

Get your source working with ppstest working before you try NTP. When 
your PPS source is set up and working, you should get something like:

locke:/usr/src/pps-tools# ./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 1297945532.000064855, sequence: 1967640 - 
clear  0.000000000, sequence: 0
source 0 - assert 1297945533.000045499, sequence: 1967641 - 
clear  0.000000000, sequence: 0
...

PPS should be connected to the DCD input. With my source (Trimble 
Thunderbolt, has a 10-20 us PPS pulse), I had to change the signal 
polarity. The RS-232 port would not "see" a positive going PPS pulse, 
but a negative going one is fine. The Thunderbolt has a command to 
change polarity. 




More information about the questions mailing list