[ntp:questions] How to debug PPS?

Steve Kostecke kostecke at ntp.org
Thu Apr 22 21:57:23 UTC 2010

On 2010-04-22, David Lord <snews at lordynet.org> wrote:

> Chaofu Chen wrote:
>> Hi all. I want to build a NTP server but PPS doen't work for the time
>> being. Status bits from "ntptime" and "ntpdc -c kern" include PLL and
>> NANO, sometimes PPSTIME and PPSFREQ, but PPSSIGNAL never appears.
> If you have a PPS signal on serial DCD, I'd suggest adding pps driver
> "server 127.127.22.(n)" which requires /dev/pps(n)

The NMEA driver (127.127.20.X) will use the PPS signal if it is present
on the DCD pin.

http://doc.ntp.org/4.2.6/drivers/driver20.html provides set-up details.

You don't need the PPS driver (127.127.22.X).

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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