1. Install CH9102X Driver

If you are doing system development and testing, the USB-to-serial TTL adapter is very useful for checking the system startup log and functional test results, especially when there is no graphical desktop display. The following shows how to use USB serial adapter CH9102X.

Signal	Function	Description
RXD	Receive	Connect to TX pin of the board
TXD	Transmit	Connect to RX pin of the board
GND	Ground	Connect to GND pin of the board
3V3	3.3V Power	No need to connect

Plug the CH9102X module to the PC, unzip CH9102X.zip on Windows, then click setup.exe to install.

Now the device will be listed under Device Manager -> Ports with unique serial port assigned.