[ntp:questions] Re: why difference about 200ms with time.nist.gov

Richard B. Gilbert rgilbert88 at comcast.net
Wed Mar 29 13:10:28 UTC 2006


flyfatpig at gmail.com wrote:

> pps /dev/oncore.pps.0 assert hardpps
> 
> 
> I don't know "assert" is raise or drop ?
> 

Why do you have that at all?????  What version of ntpd are you running?

The Version 4.2 driver says:
" * This code uses the two devices
  *      /dev/oncore.serial.n
  *      /dev/oncore.pps.n
  * which may be linked to the same device."

Create soft links pointing these "devices" to the serial port you 
connected the Oncore to.

Your driver configuration file should look something like this:
# /etc/ntp.oncore0
#
# Reference Clock configuration for Motorola Oncore M12
#
# Five Choices for MODE
#    (0) ONCORE is preinitialized, don't do anything to change it.
#          nb, DON'T set 0D mode, DON'T set Delay, position...
#    (1) NO RESET, Read Position, delays from data file, lock it in, go 
to 0D mode.
#    (2) NO RESET, Read Delays from data file, do SITE SURVEY to get 
position,
#                  lock this in, go to 0D mode.
#    (3) HARD RESET, Read Position, delays from data file, lock it in, 
go to 0D mode.
#    (4) HARD RESET, Read Delays from data file, do SITE SURVEY to get 
position,
MODE 3
#     NB. If a POSITION is specified in the config file with mode=(2,4) 
[SITE SURVEY]
#         then this position is set as the INITIAL position of the ONCORE.
#         This can reduce the time to first fix.
LAT 39 45.3782          # Positive is North.
LONG -75 04.2738        # Negative is West
HTGPS 19.61394          # Height in meters.
SHMEM  /var/log/ntpstats/ONCORE.0
TRAIM YES               #
DELAY 50 NS             # Cable delay.
MASK 10                 # Satellite mask angle in degrees.
ntp.oncore0: END

Be sure to change the DELAY, LAT, LONG, and HTGPS to values appropriate 
for your location.





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