[Voyage-linux] Re: PPS kernel patches

Fri Jan 18 05:07:58 HKT 2008

Could I also ask that GPSD gets updated too please?

This is especially useful when one needs not only NTP time but also NMEA
data around the lab/office.

On Thu, 2007-12-27 at 10:17 -0500, Mark Phillips wrote:
> I have to echo Clark's comments. 
> 
> I did solder the PPS output of my RX (no-name $5 board from ebay) to pin
> 1 DCD. This is pretty common on most OEM boards.
> 
> Like Clark I'm looking to build an appliance that "just works".
> 
> Thanks again for looking into this Punky!
> 
> Mark
> 
> On Wed, 2007-12-26 at 22:42 -0800, Clark Hartsock wrote:
> > I have been using Garmin GPS25 and GPS18 gps receivers, both of which
> > have rs232 compatible outputs. They also have a hard wired 1pps port
> > that I connected to the DCD pin (pin 1 on a 9 pin) of the connector.
> > Yes, I did need to do some soldering.
> > 
> > These work well on the big bells an whistles linux distros, but my
> > goal is an appliance that "just works" when you turn it on. The work
> > on Voyage is greatly appreciated by me because it is perfect for this
> > goal.
> > 
> > I haven't followed the kernel very closely to see if the pps patch has
> > been added to the source tree. But the links you show are for the
> > kernel. ntpd has the interface already built-in to accept pps and
> > serial data - you won't need to patch it.
> > 
> > Thanks!
> > 
> > Clark
> > kr6au
> > 
> > On Dec 26, 2007 5:34 PM, Kim-man 'Punky' TSE <punkytse at punknix.com> wrote:
> > > Mark and Clark,
> > >
> > > Don't get me wrong, but I spend a few minutes on the links below and I
> > > found that it is indeed for 2.0/2.2/2.4 kernel!?
> > >
> > > Luckily I find this one.
> > >     http://wiki.enneenne.com/index.php/LinuxPPS_support
> > > and patches here:
> > >     http://ftp.enneenne.com/pub/misc/linuxpps/patches/
> > >
> > > Including patch is OK, but patching ntpd may be a issue ... (for me).
> > >
> > > Instead, you need special equipment for getting PPS signal, at least you
> > > need soldering things.  What GPS device you usually uses for 1PPS?
> > >
> > > Regards,
> > > Punky
> > >
> > > Mark Phillips wrote:
> > > > You need to look at the NTP sources. These contain a kernel patch. If I
> > > > understand it correctly, GPSD and others pick up the 1PPS via the kernel
> > > > (usually connected to the DCD pin on the serial port).
> > > >
> > > > They are available here ftp://ftp.kernel.org/pub/linux/daemons/ntp/PPS/
> > > > and a rough howto is available here http://etienne.favey.ch/ntp/
> > > >
> > > > Thanks very much for looking at this!
> > > >
> > > > Mark
> > > >
> > > > On Mon, 2007-12-24 at 09:27 +0800, Kim-man 'Punky' TSE wrote:
> > > >
> > > >> Hi ,
> > > >>
> > > >> But where can I get the 1PPS patch for Linux and instruction?  As far as
> > > >> I read gpsd documentation, it indeed support 1PPS as long as you have
> > > >> the proper equipment.
> > > >>
> > > >> What is the different between gpsd support for 1PPS and the 1PPS patch
> > > >> for the time server?
> > > >>
> > > >> Regards,
> > > >> Punky
> > > >>
> > > >> Mark Phillips wrote:
> > > >>
> > > >>> Any thoughts/comments on this Punky?
> > > >>>
> > > >>>
> > > >>>
> > > >>> On Mon, 2007-12-10 at 14:33 -0500, Mark Phillips wrote:
> > > >>>
> > > >>>
> > > >>>> I have mine setup in a similar way but it is not a true time server in
> > > >>>> that because of the lack of a disciplining kick on a regular basis it is
> > > >>>> able to drift between time updates.
> > > >>>>
> > > >>>> The problem with NMEA time strings is that they tend to come in a
> > > >>>> cluster and not at all every second or 3 seconds or 5 seconds. They come
> > > >>>> along whenever the GPS processor has time to spit them out.
> > > >>>>
> > > >>>> The 1PPS pulse from the GPS system is not derived from the decoded data
> > > >>>> but rather is an inherant component of the GPS signal along with the
> > > >>>> 10KHz pulse and thus is more reliable.
> > > >>>>
> > > >>>> I'd still like to see a 1PPS patched kernel particularly as it would
> > > >>>> then allow for connections to things like Frequency Standards and LORAN
> > > >>>> RX's etc. Heck, one could even connect it up to the mains after a very
> > > >>>> simple signal divider (trick used on clock radios etc) is added.
> > > >>>>
> > > >>>> Mark
> > > >>>>
> > > >>>> On Thu, 2007-12-06 at 19:24 +0800, Kim-man 'Punky' TSE wrote:
> > > >>>>
> > > >>>>
> > > >>>>> Hi guys,
> > > >>>>>
> > > >>>>> Forget to mention, I have setup voyage attached to Garmin GPS18/USB and
> > > >>>>> get NTP time sync'd.  Of course, this device is not PPS-capable, but it
> > > >>>>> works without any patch to the kernel and NTP daemon.   See my blog article:
> > > >>>>>
> > > >>>>>     http://www.punknix.com/?q=node/116
> > > >>>>>
> > > >>>>> Regards,
> > > >>>>> Punky
> > > >>>>>
> > > >>>>> Mark Phillips wrote:
> > > >>>>>
> > > >>>>>
> > > >>>>>> Now I think about it, updating the gpsd package would also be useful for
> > > >>>>>> this purpose.
> > > >>>>>>
> > > >>>>>> FYI, my NTP server is running Voyage on a Neoware N3000 thin client
> > > >>>>>> (ebay $20). It has a 300MHz via processor in it as well as an IDE
> > > >>>>>> interface which is now running a CF card. The GPS RX plugs into ttyS0
> > > >>>>>> and I'm running gpspipe on ttyS1 to allow my Nixie tube clock to correct
> > > >>>>>> itself.
> > > >>>>>>
> > > >>>>>> Mark
> > > >>>>>>
> > > >>>>>> On Fri, 2007-11-30 at 05:10 +0000, Clark wrote:
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>> Mark Phillips <g7ltt at ...> writes:
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>> Hi all,
> > > >>>>>>>>
> > > >>>>>>>> Is there anywhere that I can register a feature request for adding PPS
> > > >>>>>>>> to the kernel for use in NTP apps? This would be really handy I think.
> > > >>>>>>>>
> > > >>>>>>>> Thanks
> > > >>>>>>>>
> > > >>>>>>>> Mark
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>> I would really like that too!
> > > >>>>>>>
> > > >>>>>>> I have been using Voyage to try to create an NTP appliance  'cause the
> > > >>>>>>> commercial ones are WAY beyond my budget!
> > > >>>>>>>
> > > >>>>>>> I appreciate the work on Voyage so far!
> > > >>>>>>>
> > > >>>>>>> Thanks!
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>> _______________________________________________
> > > >>>>>>> Voyage-linux mailing list
> > > >>>>>>> Voyage-linux at list.voyage.hk
> > > >>>>>>> http://list.voyage.hk/mailman/listinfo/voyage-linux
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>
> > > >>>>>
> > > >>
> > >
> > >
> > > --
> > > Regards,
> > > Punky
> > >
> > > Voyage Solutions (http://solution.voyage.hk)
> > > * Embedded Solutions and Systems
> > >   - Mesh Networking, Captive Portal, IP Surveillance, VoIP/PBX
> > >   - Network Engineering, Development Platform and Consultation
> > >
> > >
> > >
> > >
-- 

Mark Phillips, G7LTT/NI2O
Randolph, NJ