Custom carrier board UART2 problem

Robotics & Edge Computing Jetson & Embedded Systems Jetson Orin Nano
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1

For some reason the 3.3V and sys_reset lines wont go up during boot when the usb-c debug cable isn’t connected, it works with the cable connected to the host pc as long as the serial communication is received. Meaning that just connecting it to a host pc or some other power source is not enough, you need to actually start up a minicom or similiar to listen to the output for it to boot as intended.
A temporary fix to this was to disable the UART2 txd and rxd pins using the pinmux configuration spreadsheet and reflash it so that the mb1 bootloader ignores those pins. However, I would really like to have the functionality of the debug port without having to always have it connected to the host for it to boot. Do you have any idea what goes wrong based on my attached schematics below, or possibly if I could have it enable those UART2 pins in the kernel or something (after mb1) so that the 3.3V and reset-line has already gone up before re-enabling the UART2?

EDIT:
Figured I should add some more information on what each pin is:
3V3-FDTI: 3.3V from the usb-c cable
DEBUG_TXD_1V8: The TXD signal from the jetson module
DEBUG_RXD_1V8: The TXD signal from the jetson module

uart_debug_circuit
uart_debug_circuit1472×935 39.1 KB

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Hi fredrik.tegnell1,

Are you using the devkit or custom board for Orin Nano?
What’s the Jetpack version in use?

Do you mean that you have boot issue if the USB-C port is not connected?
Or UART2 for serial console(/dev/ttyTCU0) not connected?

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Hi Kevin,

I use a custom board for Orin Nano and Jetpack version 6.0 (L4T 36.2.0).
We have a USB-C port for the UART2 debug, so when I don’t have my host PC listening to the serial console through that USB-C port then I have boot issues.

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Could you verify/develop with the latest JP6.2(r36.4.3)?

Do you mean that you have custom design to use debug UART2 from USB-C?

We don’t hit similar issue on the devkit that it should boot w/o serial console or USB-C connected.

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