🛠 Accessing the BPI-5202 RS232 Serial Console

Objectifs

This tutorial guides you through establishing a serial connection with your BPI-5202. Unlike an HDMI screen that displays a graphical interface, the serial console provides access to the operating system's command line (Loongnix, KylinOS, etc.) from boot time. It is an indispensable tool for troubleshooting, initial network configuration, and managing services in text mode.

Materials required

• BPI-5202 Loongson 2K1000LA board.
• Suitable 24V DC power supply.
• A PC (Windows, Linux, or macOS).
• A USB-to-RS232 serial connection cable (or USB-TTL adapter if necessary, although the port is isolated standard RS232).
• Serial terminal software (e.g., PuTTY, Minicom, Tera Term, or Screen on Linux).

Steps

1. Hardware Preparation: Ensure the BPI-5202 board is powered off. Identify the isolated RS232 console port on the board. Connect the serial connector of the USB-to-Serial cable to the RS232 port on the board. Check pin polarity if using a TTL adapter, although the isolated port is designed for standard RS232.
2. Connection to PC: Plug the USB end of the cable into your computer. On Windows, open Device Manager to identify the associated COM port number (e.g., COM3 or COM4). On Linux, the device will usually appear as /dev/ttyUSB0 or /dev/ttyACM0.
3. Terminal Configuration: Open your terminal software. Configure the following communication settings, which are standard for this type of industrial interface:

• Baud rate: 115200
• Data bits: 8
• Parity: None
• Stop bits: 1
• Flow control: None

1. Open Connection: Start the connection to the serial port identified in step 2. The terminal window should remain empty or display gibberish if the speed is incorrect.
2. Board Startup: Connect the 24V DC power supply to the BPI-5202. Press the power button if necessary.
3. Observe Boot: You should see the LoongArch kernel and bootloader startup messages. If nothing appears, check the COM port number and speed settings.
4. Access Command Line: Once the system loads, press Enter. You should see a login prompt. Log in with the default user (often root or a standard user provided by the system image) and the associated password.

Verification

To confirm the connection is stable and functional, type the command uname -a in the terminal. You should receive a response displaying the kernel name, version, and LoongArch architecture. Also try the free -h command to verify the system recognizes the 4GB DDR3 memory. A successful connection is characterized by the absence of weird characters (garbage) and smooth interaction between your keystrokes and the board's responses.

To go further

Once you master the console, explore hardware diagnostic commands like dmesg to read kernel messages, useful for detecting memory or SSD storage errors. You can also configure SSH access to administer the board remotely via Ethernet, once the IP address is correctly assigned via the serial console.