[LinuxPPS] Oncore

[clemens at dwf.com]

> On Mon, 2010-07-05 at 20:25 -0600, clemens at dwf.com wrote:
> > > I am now playing with an oncore unit. I have quite a basic problem, it
> > > doesn't appear to work (the unit that is). The PPS appears OK, my
> > > interface board drives a LED which blinks encouragingly, and I see the
> > > Asserts etc. But the data out appears mute. The pin on the oncore just
> > > sits at 5V. Is there something else I need to do? I have an interface to
> > > data in on the oncore. 
> > > 
> > > 
> > Im sure the answer is going to be 'yes', but are you trying it with ntp?
> > If the answer is yes, then I have no idea, or will at least have to think
> > about it.  Which ONCORE is this anyway?
> > 
> > If the answer is NO, then try it with ntp, there is a startup command that
> > ntp issues that might clear up the problem.
> Yes I am using it with NTP. How does ntp know to issue that command?
> >From the presence of the line in ntp.conf? I have such a line (the
> 127.127.30.0 one) and ntp.oncore.0 - do I need more? When does ntp issue
> this startup command - at startup or whenever it cannot see time data?
> Reg - I am using some very old configurations which you posted on a
> forum - are there more recent examples?
> 
> 
Let me ask this question again: Which ONCORE Receiver is this anyway?

As to your other questions, nothing of importance has really changed.
In your ntp.conf you will need a line of the form:

         server 127.127.30.0 prefer

in the ntp.oncore.0 file that goes with this line, really the only thing
that is necessary is a line that says either

        ASSERT
or 
        CLEAR

depending on how the support board for your ONCORE is wired.

If you look at the timestamps with one of the programs that prints them,
the timestamps will not be spaced evenly (ASSERT-CLEAR-ASSERT-CLEAR)
but rather one pair will be about 20ms apart, the other 80ms.  It is this first
pulse that you want to specify, be it ASSERT or CLEAR, it is the PPS signal
that the ONCORE is producing, the 2nd is just a 'return to original state' 
based on a RC circuit.

You can say other things, but these are for later, Your Position (lat,long,ht),
the keyword  HARDPPS if you are trying to use the GORDEEV kernel changes,
and possibly MASK to only use satellites that are a specific amount above the
horizon (I use MASK 10).

[[ Note that if you DONT give your position, its going to take the ONCORE driver
a couple hours to really get started (10000sec), you should be watching the
clockstats file to see what is going on, you need the following three lines in
your ntp.conf to get it:

statsdir    /var/log/ntpstats/  # directory for statistics files
statistics clockstats
filegen clockstats file clockstats type day enable

You also need the symbolic links (in /dev)

        oncore.pps.0 -> /dev/pps0
        oncore.serial.0 -> /dev/ttyS0

which you get with the lines:

        ln -s /dev/ttyS0 /dev/oncore.serial.0
        ln -s /dev/pps0  /dev/oncore.pps.0

And you need to run ldattach (or one of the equivalent programs)
on /dev/ttyS0 to get linuxPPS to actually create the /dev/pps0

And I like to walk thru the /sys file to verify that it was /dev/pps0 that
was created,- if you have been playing with things for a long time, you
might just be creating a /dev/pps1 or 2, and not see any signal on /dev/pps0

I think that answers all your questions, give it another shot, and let me know
how it goes.

As for your other question, NTP can only do its ONCORE startup when IT starts,
so restart ntp.
    
Just for reference, here are my /etc/ntp/ntp.conf file (I start ntp with 'ntpd -c /etc/ntp/ntp.conf')
and my /etc/ntp/ntp.oncore.0

---# NTP configuration file (ntp.conf)
###### NTP V4 ####

# Miscellaneous stuff
driftfile   /etc/ntp/ntp.drift  # path for drift file
logfile     /var/log/ntpstats/xntpd
statsdir    /var/log/ntpstats/  # directory for statistics files

statistics loopstats peerstats clockstats sysstats rawstats
filegen loopstats  file loopstats  type day enable
filegen peerstats  file peerstats  type day enable
filegen clockstats file clockstats type day enable
filegen sysstats   file sysstats   type day enable
filegen rawstats   file rawstats   type day enable

### Kernel PPS Selection
enable kernel

### Configuration section ###

server 127.127.1.0                      # Local clock
fudge  127.127.1.0 stratum 8            # Local stratum

server 127.127.30.0 prefer              # ONCORE #1

# server 127.127.30.1 prefer              # ONCORE #2

## server 127.127.28.0                     # SHM/WWVB
## fudge  127.127.28.0  time1 0.0251750

# Peer Section

peer clemens-fw.dwf.com
peer mythtv.dwf.com
peer mythtv-fe.dwf.com
peer orion.dwf.com

# External Servers

# server time.nist.gov
# server tock.usno.navy.mil

---


#
# this is a sample ONCORE Data File.
#

Mode  1

lat 35 9 0.126
lon -106 34 36.225
# ht 5115.71 ft
ht 1589.748 m

delay = 65 ns

offset = 100 us

# ONCORE VP   Triggers on ASSERT
# ONCORE M12  Triggers on CLEAR (dead)
# ONCORE M12T Triggers on ASSERT

ASSERT
# CLEAR
  HARDPPS

MASK 10

SHMEM  /var/log/ntpstats/ONCORE.0
Posn3D

# TRAIM   off

---

note that there are a lot of lines commented out, that are there
for historical reasons...

-- 
                                        Reg.Clemens
                                        reg at dwf.com