UART 0 can't be accessed on Auvidea J90 with Jetson TX-2

Hello ,everyone!

I am having troubles with the UART 0 port of Auvidea J90 carrier board with Jetson TX-2. That port doesn’t react at all using write/read operations on it. Within the dev directory ttyTHS1, ttyTHS2 and ttyTHS3 are available. On UART 2 interface I attached another serial device and it works perfectly through the ttyTHS1. But UART 0 can’t be accessed with the current firmware version 1.5 (kernel and patches) for J90/J100/J106/J120/J130/J140 and JetPack 3.2 with L4T 28.1.

Within the Auvidea J90 documentation I found this:

On the J90-LC the UART 0 is directly connected to connector J14. On the
J90 UART 0 is tunnelled through the on-board micro controller (MCU) and then connected to J14. This allows
the MCU to monitor the UART 0 communication for watchdog applications.

Do I need to control the MCU functionality in order to access UART 0?

Any ideas for resolving that issue will be highly appreciated.

Thank you.


hello it_engineer,

since you’re able to access other UART port directly, you may also contact Auvidea team to help dig into this issue.
BTW, we already update JetPack release, could you please verify this issue with latest JetPack release.

Hi Jerry Chang,

I’ve already started a ticket at the Auvidea support team but still no any reasonable reply.

I’m gonna test and see what will be the situation with the newer JetPack ver. 3.3

Thank you

Hi it_engineer,

Have you made any progress in regards to accessing UART 0? I am currently using UART 2 as well, but would like to have both available. I have not spent much time on this yet, but will be over the next week or so. Keep me updated as to what progress you have made and let me know if you would like me to do any testing on my end. I have both j90 and j90_LC versions I can work with.


Hi austin70i2l,

Following the Nvidia moderator JerryChang advice for finding any solution for resolving of not working UART 0 port on J90 (as well as J90LC - both tested), I opened a ticket to Auvida support team but until this moment no any reply from them.

Still waiting for any ideas how to resolve it.