[RS232][JetsonTK1] Disabled DTR pin?

Hello community!

I’ve got a question about serial communication in Jetson TK1. It took me a lot of time to get default serial port working (ttyS0) and this link (http://unix.stackexchange.com/questions/217342/setserial-dev-ttys-uart-is-undefined) was really helpful. But now I’m facing the problem with disabled DTR line. The device I want to connect to the board needs this line to be in logic 1 state but I don’t know how to set it. I’ve read there is setserial program to manage serial port parameters but I can’t find needed option. Does anyone had similar problem? I would really appreciate any help :)

Best,
Daniel

Look at the schematic for the Jetson.

It looks like the DTR signal is looped back to the DSR signal via a resistor. The schematic also seems to indicate the resistor is a no fit.

Additionally, the TRM says that only UART1 support DTR, DSR and DCD signals.
The Jetson schematic does not show UART1 as having any of these signals connected.

The UART going to the 9pin D is UART4 according to the schematic

Thank you very much for your help, it solved my problem. :)

Best,
Daniel