No signal measured while echo to ttyTHS0 / ttyTHS3 / ttyTHS4

Autonomous Machines Jetson & Embedded Systems Jetson Orin NX
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1

Hi,
We use JP5.1.3 on a custom carrier board.
We configured the PINMUX and the debug UART (ttyTCU0) works fine.
When we echo into /dev/ttyTHSX (X=0/3/4) we don’t see any signal on the line.

There are some serial@Address dt nodes that currently disabled, but we don’t know how to match the /dev/ttyTHSX device (or the UART port) into the appropriate serial device tree node.

How can I know the mapping and then maybe discover that the selected UART port is disabled in the dt?

Thanks

3

Hi bsp_dev,

You can refer to the UART mapping from Jetson/L4T/peripheral/ - eLinux.org.

4

Thanks, I fear the mapping is not relevant for Orin NX?
We use Orin NX on a custom carrier board.

We don’t understand how the debug uart works since in our final DT the uartc@c280000 is disabled.
We missed something here?

5

You can refer to the one as Jetson Orin Nano devkit for Orin NX, they have the similar design.

There’re 3 physical UART interfaces for Orin NX/Nano.
One is from M.2 Key E(J10), One is from 40-pins expansion header(J12), One is from Button header(J14) for Tegra Combined Uart.

There’re many Uart address defined in device tree, but some of them are the virtual ones or reserved.
Tegra combined UART would output the debug messages from several firmwares for debug purpose.
uartc@c280000 is used when you disable it to be used as debug UART.
We don’t suggest and have not verified for this use case.
So, you can just ignore this node.

6

Thanks for the quick help

8

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