Add PPS signal from gnss reciever to xavier nx

[dinartal]

I found how to do that for jetson nano:

Enabling PPS on Jetson Nano

i have stopped on:

• Add PPS gpio support. In ~/nvidia/nvidia_sdk/JetPack_4.3_Linux_P3448/Linux_for_Tegra/sources/hardware/nvidia/soc/t210/kernel-dts/tegra210-soc edit tegra210-soc-base.dtsi and add the following lines

because there is no folder “sources” in my Linux_for_Tegra folder.
Help me please to use PPS signal with ntp and gpsd.

[linuxdev]

Depending on where your kernel source is from you might not have the out of tree content. When unpacking from the NVIDIA-supplied source code it creates this:

└── sources
    ├── hardware
    │   └── nvidia
    └── kernel
        ├── kernel-4.9
        ├── nvgpu
        └── nvidia

…where the “kernel-4.9” is the actual kernel source. The other content is sometimes accessed if an NVIDIA feature is enabled (the feature uses files which use a relative path into those other subdirectories).

Which L4T release are you using? One of either “head -n 1 /etc/nv_tegra_release” or "dpkg -l | grep 'nvidia-l4t-core' will tell you which release. Then go to that release in this list of releases (you might need to go there, log in, and go there again):
https://developer.nvidia.com/linux-tegra

Within this will be " L4T Driver Package (BSP) Sources". When unpacked you will find a sources package for the kernel, and then you’d unpack that package which was in the set of packages. This has the directory tree structure listed above with “sources/” as the first subdirectory.

[Andrey1984]

@dinartal
which gps unit do you use?
we used ardusimple with nano/AGX/nx via uart+ usb/NMEA & pps
ref:

Enabling PPS on Xavier AGX

modprobe pps-ktimer ppstest /dev/pps1 so this one won’t show the timepulse if you run it? with connected gps device? without connected gps device? what will be the output? On NX I was able to use jetson.io & dtb update in order to add the timepulse; Pin number is to be checked with reference documentation. The example below matches pin7 of NX GPIO. In my implementation I used following steps for NX: creatednew file pps.dts at /boot folder /dts-v1/; /plugin/; / { overlay-name = "Jets…

Time sensitive networking [TSN] on NX

Hi @gtj on the fresh OS from sdcard image, after patching It is staying blank with a flash _ [ as per the observatino of local person] from remote dev: “Nothing is showing except the _ flashing on the top left” [IMG_20200622_113956]

[dinartal]

thank you
now, ppstool show me timestamps of pps signal.
could you please tell me how configure gpsmon to attach pps? right now it is blank.
and how can i configure ntp?

[Andrey1984]

@dinartal

could you please tell me how configure gpsmon to attach pps? right now it is blank.

I am just curious which gps unit model did you connect
I did not have experience with gpsmon
we used ardusimple u-center on windows computer
ref : https://manpages.debian.org/testing/gpsd-clients/gpsmon.1.en.html
http://manpages.ubuntu.com/manpages/bionic/man1/gpsmon.1.html

[dinartal]

I have small progress on my task, but i still need help:
i have launched gpsd ( sudo gpsd -N -D3 -F /run/gpsd.sock /dev/ttyTHS0 /dev/pps0 ):

gpsmon:

cgps:

if i launch gpsd as deamon, gpsmon show PPS also, but ntp not recieve PPS.

service statuses show running green without errors

ntp.conf contain:
server 127.127.28.1 prefer
fudge 127.127.28.1 refid PPS

How can i fix that?

[dinartal]

The problem is solved. Correct address is 127.127.28.2