16. SERIAL PORTS

This page describes the serial port software configuration details change the protocol modes.

The serial ports on the Nano & Xavier NX are available at different device IDs. The device IDs are provided as below:

Jetson Nano

SER 1 --> J1 --> ttyTHS1

SER 2 --> J9 --> ttyTHS2

Jetson Xavier NX

SER 1 --> J1 --> ttyTHS0

SER 2 --> J9 --> ttyTHS1

From the transmitter node, it is essential to enable the RTS during transmit & disable it thereafter. Since, the auto RTS feature is not supported on Nvidia serial port drivers, the RTS signals would need to be enabled manually just before transmit & disabled right after the transmission. The following commands are used for these purposes:

On Nano:

sudo rs485_util ttyTHS2 1; // enable RTS for SER 2 (J9)     
                           // to transmit
sudo rs485_util ttyTHS2 0; // disable RTS for SER 2 (J9) 
                           // to receive

On Xavier NX:

sudo rs485_util ttyTHS0 1; // enable RTS for SER 1 (J1) 
                           // to transmit
sudo rs485_util ttyTHS0 0; // disable RTS for SER 1 (J1)
                           // to receive