Serial USB to TTL cable

I made a code on Jetson nano and developer kit with python that can read and write informations and commands in other equipaments.The code has somes Threads in python for reading and writing list commands.

The “data” from other equipaments it’s like 2 alphanumerics ASCII-HEX(8bits). But when I start to read and write in Jetson, the “data” comes broken and gives me a lot of characters that ASCII does not consider. I tried to use decode and encode, but it didn’t work better.

I don’t know if this is a software issue or not, but is your UART 3.3V logic level? If not, this is a problem. Also, default of the UARTs on the Jetson is 115200 8N1. Make sure the other UART is using matching settings (no CTS/RTS). Also, make sure cables are not too long and of reasonable quality (I like testing with ethernet cable).

Note that one of the UARTs is normally running as a serial console, which means if you use that without disabling the console, then it is the same as typing random text into a terminal, and getting the terminal’s response. If you look at the serial UARTs with “ls -l”, then the console one is group “tty”, while the devices not console are group “dialout”. What do you see from your specific device if you run this command on the Jetson?
ls -l /dev/ttyS* /dev/ttyTHS*

You could replace the full list of tty’s in the above with your specific device, e.g., “/dev/ttyTHS1” would be an example.

I modified from 5v to 3v in my converter USB to TTL, the program works better ! But I have 2 types of converter USB. When I use the converter in the left of the image I don’t have problems, but when I use the converter on the right of the image the serial does not communicate with Jetson, the information is not received. I will send one image of the cable that I’m using to collect information.

hello marco.cruz,

please access Jetson Nano Product Design Guide via download center for reference,
as you can see, it’s [Jetson Nano UART Connections] show typical assignments of the three available UARTs.

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