Re: [gpsd-users] PPS to gpsd from Pi GPIO pin

[Gary E. Miller]

Yo Pete!

On Wed, 9 Mar 2016 11:10:23 +0000
Pete Nevill <address@hidden> wrote:


> source 0 - assert 1457520371.538039843, sequence: 180814 - clear 
> 0.000000000, sequence: 0
> 
> Yes... we are cooking.

Uh, not really, your clear is always 0.  That is a known kernel bug with
a known kernel patch.

> It appears to look in the right place "pps0" but then ignores it,

I see no evidence in your log that gpsd found your /dev/pps0.  Why
do you think it did?

Also, what is the command line taht started your gpsd?  Did the command
line include /dev/pps0?


> I guess I do not understand the
> link with ttyUSB0 and PPS.

Usually, not on RasPi, the serial device (ttyUSB0) and the pps device
are the same, since the PPS is coming in on the same serial port.

the RasPi leaves out the serial control lines, which is why you had to 
use the GPIO pin, and why there is no obvious conenction between the USB0
and the pps0, unless you tell gpsd how to make that connection.


> It then creates its own pps device
> on /dev/pps1 which is linked to ttyUSB0

Yup, becuase in 99% of cases that is the right thing to do.  Just not
on the RasPi in your configuration.

> but we know that PPS is

What you mean 'we' white man?  Unless you told gpsd on the command line to
look at pps0 it has no idea it should.


> I tried to trick gpsd by creating a symlink to pps0 from pps1 "sudo
> ln -fs /dev/pps0 /dev/pps1". The ppstest worked on pps1 as it is now
> linked to pps0 but when I run gpsmon again still empty pps section, I
> guess gpsd has no knowledge of either as it sort of failed during
> initialisation.

The kernel is prolly letting gpsd create a pps2 then.

> Any suggestion or am I asking too much?

Fix your command line?

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

pgpcZqN6_mG6k.pgp
Description: OpenPGP digital signature