Re: pulse-per-second API status

["David Lord" <netbsd%lordynet.org@localhost>]

On 31 Oct 2013 at 19:52, Greg Troxel wrote:

> 
> I just got a Navisys GR601-W GPS receiver, which provides a PPS signal
> on DCD via a PL2303.  Looking into using it with ntpd and gpsd on
> NetBSD, a bit of work is needed.  This note describes my impressions of
> what's needed; please let me know if I'm off or if any of this is
> controversial.
> 
> * sys/timepps.h
> 
> NetBSD has sys/timepps.h for RFC2783 support, but the comments reference
> an older internet-draft.  So it needs to be checked for conformance and
> at least the comments updated.
> 
> * compare with FreeBSD and OpenBSD
> 
> It's likely pps support in FreeBSD is better, and this needs checking as
> it should be easy to snarf the improvements.
> 
> * ucom(4) needs pps support
> 
> On -5, trying to use pps on a 16450 serial line (i386) to which no PPS
> is connected appears to work right.  But the ioctls error on ucom(4)
> interfaces.
> 


Hi

I'm currently on NetBSD-6 i386 with a Sure GPS and ntpd 4.2.7p393
from www.ntp.org running from /usr/local/bin. Kernel is built 
with "options PPS_SYNC" and offsets are usually within +/- 5 usec
but with blips of 100 usec or more when system is under heavy 
load (eg. as just now after compile of a couple of packages). 
I've not bothered to check on any improvements there might be
with PPS from FreeBSD but would be interested. Main problem here 
is lack of temperature control of my house and I intend to make 
an add on ovened system clock source.


David

############################################
Script started on Fri Nov  1 14:40:49 2013
bash-4.2$ /usr/local/bin/ntpq -c rv -p
associd=0 status=011d leap_none, sync_pps, 1 event, kern,
version="ntpd 4.2.7p393@1.2483-o Wed Oct 30 09:50:29 UTC 2013 (1)",
processor="i386", system="NetBSD/6.1_STABLE", leap=00, stratum=1,
precision=-17, rootdelay=0.000, rootdisp=400.015, refid=PPSb,
reftime=d61e3c1b.244b6264  Fri, Nov  1 2013 14:41:31.141,
clock=d61e3c1c.cf0b29e8  Fri, Nov  1 2013 14:41:32.808, peer=55992, 
tc=4,
mintc=3, offset=-0.012560, frequency=-35.852, sys_jitter=0.007629,
clk_jitter=0.004, clk_wander=0.010, tai=35, leapsec=201207010000,
expire=201312010000

     remote           refid      st t when poll reach   delay   
offset  jitter
======================================================================
========
-GPS_NMEA(2)     .GPSb.           7 l   29   64  377    0.000   
20.659   4.820
oPPS(2)          .PPSb.           0 l    1   16  377    0.000   -
0.013   0.008
############################################