Using the ttyS0 UART located on J50

Hi - I’m trying to use the UART on J50 “Debug header” but I don’t see any data being sent on the line. I’ve tested a piece of code that uses the GPIO UART and verified it is valid but when I change the serial port settings from ttyTHS1 to ttyTHS2 there is no data on the port.

I’ve verified that the J50 debug header UART TX signal is capable of sending data by rebooting the nano and scoping the TX signal and data activity is present.

In searching for help on this topic I’ve added my user name to the dialout group:

sudo usermod -aG dialout name

This did not fix the issue.

What else am I missing? Any help would be greatly appreciated.


hello JamieBasil,

had you also update device tree configuration to change the mappings?

Hi JerryChang,

I have not updated the device tree. Sounds like this is what I’m missing.

I found the device tree mention in tegra210-porg-p3448-common.dtsi:

	serial@70006000 { /* UART-A : UART1: Debug */
		compatible = "nvidia,tegra210-uart", "nvidia,tegra114-hsuart", "nvidia,tegra20-uart";
		/delete-property/ resets;
		/delete-property/ reset-names;
		status = "okay";

Is this the correct code block to update?

What update do I make?

Thank you!

The error I was making was assuming that it was ttyTHS2 when it’s supposed to be ttyS0. I didn’t need to make any device tree changes. Just had to call the correct port. I now see serial data out of the J50 header.