OrinNX : How to check UART is working?

[sumin.lee1]

Hello,

We want to use all 3 channels uart port.
Basically, all of the uarts looks those are enabled.

We designed 3 ports of uart on the board.

It works like as follows:
UART0 - uartb -??
UART1 - uarta - /dev/ttyTHS0
UART2 – uartc - /dev/ttyTCU0

There is two questions :

1. ‘uartb’ is not working with any ttyTHS*. How to check it ?
2. Could I use 'uartc ’ as the ‘ttyTHS*’ ?

[KevinFFF]

Hi sumin.lee1,

What’s your carrier board for Orin NX?

Please refer to the following table from Jetson Orin NX Product Design Guide for UART.

and also refer to the pinmux table and tegra-soc-uart.dtsi.
You would get the following information of UART, there are 3 UART.

Module UART# => SOC UART#(used pins): <uart*>@\<address> - \<node> => Usage

• UART0 => UART2(PX04, PX05, PX06, PX07): uartb@3110000 (serial1) - Unused => To M.2 Key E
• UART1 => UART1(PR02, PR03, PR04, PR05): uarta@3100000 (serial0) - /dev/ttyTHS0 => General UART
• UART2 => UART3(PCC05, PCC06): uartc@c280000 (serial2) - /dev/ttyTCU0 => Debug

For uartb, it connect to M.2 Key E port, you need soldering by yourself to use.
For uarta, it could be simply used at /dev/ttyTHS0 node
For uartc, it is debug usage currently as you could output the serial console log. If you want to use it, you should disable the combined-uart and you would not get the debug messages.

[sumin.lee1]

Thanks for the kindly comment.

And the ‘uartb’.
We don’t use the M.2 Key E on our custom board.
And we can connect uartb pin directly.
How can I use it in this usecase?

[KevinFFF]

If you don’t use M.2 Key E, then you can use this UART connecting to your peripheral device. Just make sure you configure it correctly in pinmux table and also enable them in device tree(uartb@3110000).