[LinuxPPS] Kernel configuration and more ......

[Paul]

My GPS unit generates MNEA data and PPS output.
I have checked that the PPS signal appears on the DCD pin (it causes the
meter needle to kick every second).

The pulse from this unit is short (25 mS.), but this has worked on a PPS
kernel from before the big changes (i.e 2.6.19 or so).

I know NMEA data is being generated because I see it using minicom.

I know the DCD pin is being pulsed because I use Statserial. This is a
command line program which gives the levels on all the control pins for
the serial port. So usually it gives a 0 on the DCD pin, but sometimes
it gives a 1 (which is what you would expect from a short pulse.)

PPS and the 8250 are compiled in, so when I boot up the
directory /sys/class/pps is generated, but is empty.

When I ppsctl the /dev/ttyS0, the files in /sys/class/pps/pps0 are
generated, exactly as I would expect.
# cat /sys/class/pps/pps0/assert
1193688471.903089607#599
every time I try it
which tells me the PPS pulses are not being registered

The next bit is interesting
ktimer is as a module so
# modprobe ktimer
new PPS source ktimer at ID 1
ktimer PPS source registered at 1
#    (now the data starts)
PPS event at 19570298
PPS event at 19570548
PPS event at 19571048
PPS event at 19571298
PPS event at 19571548
PPS event at 19571798
and it just goes on and on

But
# tree /sys/class/pps  (Difficult when the events keep writing on top)
shows another PPS, PPS1
which looks like PPS0 except there is no device line (with only one
serial line active in the BIOS)

# rrmod ktimer (difficult when you can't see what you are typing.)
stops the event output.

I think the events are NMEA data as these come at about this rate.

What more can I try?

Paul

On Mon, 2007-10-29 at 16:57 +0100, Rodolfo Giometti wrote:
> On Mon, Oct 29, 2007 at 03:17:54PM +0000, Paul wrote:
> > On Mon, 2007-10-29 at 15:04 +0100, Rodolfo Giometti wrote:
> > > On Mon, Oct 29, 2007 at 01:39:10PM +0000, Paul wrote:
> > > > First of all I compiled with the debugging messages. I got 4 events
> > per
> > > > second to the screen (this is why I need to know if debugging is for
> > the
> > > > PPS and/or GPS NMEA data).
> > > 
> > > Debugging are for both.
> > 
> > So I think the events I see are NMEA data, I can get the same if I
> > modprobe ktimer (and then rmmod ktimer before it sends me crazy)
> 
> Can you please post them?
> 
> > > > I compiled exactly the same with no debugging.
> > > > The /sys/class/pps/pps0/{assert/clear} remain at 0.000
> > > > I checked the voltages on the serial plug and I saw the PPS pulses
> > on
> > > > the DCD pin. I checked with statserial (which actually looks at
> > voltages
> > > > on the serial pins) just to be sure I did not have a hardware
> > problem.
> > > 
> > > Looking at /proc/interrupts, do you see increments on the IRQ counter
> > > for the serial line?
> > > 
> > 
> > No the serial stays the same.
> 
> So your system doesn't see any interrupt from the serial line... then
> you can't see PPS events. Verify if your hardware is correctly setup.
> 
> > > Rodolfo
> > > 
> > 
> > I also tried ./ppsfind ktimer which does not do anything.
> 
> Did you load ktimer module?
> 
> > ./ppstest /dev/pps0 just errors with timeouts.
> 
> Which error? Please, post it.
> 
> Ciao,
> 
> Rodolfo
>