I wanted to have a communication with Xsense-670 IMU over UART. How should i start? Are there any examples available specifically for Xavier uart interfacing?
Jetson UARTs are more or less the same as any PC’s UART, or small device. Mainly the question is knowing which UART you will use and making sure the voltage level is compatible with your device. Also keep in mind that one UART is already in use by the serial console.
The default serial devices on a Jetson will have a file designation of either “/dev/ttyS0” format, or “/dev/ttyTHS0” format (the “0” varies, it is the “S” or “THS” to beware of). The ttyS0 is the same UART as the ttyTHS0, but one does not use DMA, and the other does use DMA. You would use only one driver at a time on a given UART, e.g., you might do everything with “/dev/ttyTHS1”, and never touch “/dev/ttyS1”, or the reverse (ttyTHS1 and ttyS1 are the same physical hardware).
You might be interested in this listing of the 40-pin header:
https://www.jetsonhacks.com/nvidia-jetson-agx-xavier-gpio-header-pinout/
The micro-B USB cable also provides some serial devices, and the first listed serial device is serial console (and thus you would not be able to use that). Note that the 40-pin header uses a 3.3V logic level. A typical use might run at speed 115200, 8-bit, no parity, and 1 stop bit (115200 8N1).