Orin NX UART1 CTS/RTS failed on JetPack6

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

Hi Nvidia,

I used burninTest tool arm version to test the UART1 CTS/RTS on JetPack6.
The TX/RX is passed.
But if I enable CTS/RTS, the testing is always failed.
I see the CTS/RTS have some issue on JP5. Does it fixed on JP6?

LT4 36.4.3
Orin NX 16GB
Orin Nano Devkit Carrier Board

3

Hi Wilson_Lin,

We’ve verified UART with HW flow controlled enabled working on the devkit with Jetpack 6.2(r36.4.3).

Could you try to simply verify it with loopback test? (by shorting RX/TX, RTS/CTS)

$ sudo su
# stty -F /dev/ttyTHS1 115200 crtscts raw  -echo
# cat /dev/ttyTHS1 &
# echo "test" > /dev/ttyTHS1
4

Hi Kevin,

I can get the “test” result after enable crtscts.
Does it means the RTS/CTS is worked fine?
So, is it possible that this issue is caused by the BurnInTest tool itself?

5

Yes, it means that UART transaction works as expected with RTS/CTS enabled.
You can also get a scope to check the state of RTS/CTS during data transaction.

We’ve not verified that tool. I would also suggest you get a scope to check the signal.

6

Hi Kevin,

But I didn’t short the RTS/CTS pin.
The UART still can get the “test” result.
It’s weird.

7

I don’t know if this is the case, but the UART will typically remember what “mode” or state it is in; if CTS/RTS was enabled at some point, then it probably remains enabled until something changes it; conversely, if disabled, then it probably remains disabled until something re-enables it.

8

You can also try to perform the loopback test with larger file instead of just a string and get a scope to check the state of RTS/CTS.