Re: gpsd + chrony + pps

[Dan Williams]

> I found the chrony.pps0.sock trick here:

1.

First off, there is also the official gpsd howto on this -- https://gpsd.gitlab.io/gpsd/gpsd-time-service-howto.html -- it's not without issue, but it tends to be up-to-date.

2. 

It's important to distinguish between the input socket (is GPSD receiving the PPS signal?) and the output  (is gpsd communicating PPS signal to chrony?)

"chrony.pps0.sock" is the latter.  It's an output signal from gpsd to chrony.

What steps have you progressed through, to verify that the PPS signal is being received by the OS?

Daniel Williams  |  Software Engineer

dwilliams@nextdroid.com

On Sat, Jun 13, 2020 at 3:31 AM Stéphane Péneau <stephane.peneau@wanadoo.fr> wrote:

Hi !

Le 12/06/2020 à 14:54, Dan Williams a écrit :

For reference:

1. What OS brand & version are you using? 

armbian (debian buster based)

2. Are you running this on a RPi, or a x86 computer?

Orange pi zero (arm). PPS is on gpio.

I just set this up last week with a serial/pps line + intel computer + gpsd- (3.20 / master) + chrony (2.11).   So, it definitely _CAN_ be done, but the setup can be finicky.

It's a very different setup, your timepulse is on the tty

I found the chrony.pps0.sock trick here:

https://medium.com/@srfilipek/chronos-a-stratum-1-time-server-e7a89cd808bc

(beaglebone and timepulse on gpio)

Stéphane

Daniel Williams  |  Software Engineer

dwilliams@nextdroid.com

On Fri, Jun 12, 2020 at 6:03 AM Stéphane Péneau <stephane.peneau@wanadoo.fr> wrote:

Hi!

I've made many tests to use the timepulse output on my U-blox ZED-F9P
with gpsd and chrony to get an accurate time.

I've never had a working solution if I try to use a socket like
chrony.ttyXX.sock.

But if I replace 'ttyXX' with my 'pps', it works.

refclock SOCK /var/run/chrony.pps0.sock refid PPS2 lock GNSS <== OK

refclock SOCK /var/run/chrony.ttyACM0.sock refid PPS2 lock GNSS <== NOK


Is there a mistake in the documentation ?

Stéphane