[ntp:questions] Fwd: Re: NetBSD GPS/PPS using 4.2.6p3

A C agcarver+ntp at acarver.net
Thu Aug 25 20:23:01 UTC 2011

On 8/25/2011 10:35, Daniel Hagerty wrote:
> Dave Hart<hart at ntp.org>  writes:
>> On Wed, Aug 24, 2011 at 07:52, A C<agcarver+ntp at acarver.net>  wrote:
>>> So it seems like a port contention issue though I don't understand why
>> It may be specific to NetBSD.  The Windows port of ntpd has special
>> code in refclock_open() and tty_open() to duplicate rather than
>      I'm running NetBSD 4.0.x i386 with ntp 4.2.4p2 (netbsd 4's
> distributed version) using both the NMEA(20) and PPS(22) clocks on the
> same port.  No issues.  ntp.conf looks much like what others have
> suggested.
>      One thing I'm doing differently from the OP is that the
> /dev/{gps,pps}1 devices point at dtyXX, rather than ttyXX.  The
> difference between the two being that dtyX defaults to CLOCAL (ignore
> DCD state), whereas ttyX is ~CLOCAL.  Since PPS is usually on DCD,
> this might be relevant.  I have no idea if NTP adjusts CLOCAL on open.

I am willing to try anything so I gave it a shot but it didn't work.  I 
still get a "kern PPS no signal" message if NMEA and PPS are both 
enabled.  Using PPS alone with /dev/pps1 pointing to /dev/dtyb works 
fine.  So there's still some type of contention going on.

I'll still have to put a serial monitor on the line and try to figure 
out what is being transmitted towards the GPS when the PPS driver is active.

More information about the questions mailing list