Flashing the Jetson to configurate the GPIO pin for PPS purpose

Products & Technology
#1

Hey community,

for my Project I’m trying to enable my Jetson on J401 carrier board to receive a PPS signal from GPS-Reciever. From my understanding what I have to do:

  1. Recompile kernel with configuration in .config:

#PPS support

CONFIG_PPS=y
CONFIG_PPS_DEBUG=y

#PPS clients support

CONFIG_PPS_CLIENT_KTIMER=y
CONFIG_PPS_CLIENT_LDISC=y
CONFIG_PPS_CLIENT_GPIO=y

  1. Add to the dtsi file with (I want to use GPIO09 pin 7):
pps {
gpios = <&gpio TEGRA234_MAIN_GPIO(AC, 6) GPIO_ACTIVE_HIGH>;
compatible = "pps-gpio";
status = "okay";
};

  1. Build the kernel

  2. Copy Image to the kernel folder of my installation and device tree files into dtb folder

  3. and simply flash the Jetson

My problem is that the pin that I set, does not work and Jetson sees it not like PPS-In. I can start

ppstest dev/pps0/

and get the kernel-PPS, but the

ppstest dev/pps1

comes with

time_pps_fetch() error -1 (Connection timed out)

I checked the generated device tree file in boot/dtb/…dtb, and the PPS-device with the configurated pin is there.

Am I doing something wrong? And how can fix/debug it?