Add PPS signal from gnss reciever to xavier nx

I found how to do that for 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.

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.

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


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?

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

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?

The problem is solved. Correct address is 127.127.28.2

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