How to Use Serial Redirection on the LattePanda 3 Delta

Overview

LattePanda's serial redirection function allows for "headless" operation, letting you control and manage the LattePanda board without needing a connected monitor, keyboard, or mouse.

Specifically, you can:

1. Use a standard laptop or desktop computer; 
2. Connect to the LattePanda board via an RS232 serial cable; 
3. Run simple terminal software, like PuTTY, on your computer; 

This enables you to:

1. Directly view and modify LattePanda's BIOS settings;
2. Install a Linux OS as if you were directly operating on the board;
3. Perform various management tasks without physically touch the LattePanda board;

This method is particularly beneficial for managing multiple LattePanda boards, greatly enhancing efficiency, especially during batch deployment and management of devices.

This article uses the LattePanda 3 Delta as an example to explain in detail how to enable the serial redirection function and view BIOS settings using the terminal software PuTTY.

Preparation

Hardware

- LattePanda 3 Delta

- USB to RS232 Converter

- DB9 to Pin Header Cable

Software

- Terminal Software, e.g.PuTTY(https://www.putty.org/)

- BIOS Firmware (https://docs.lattepanda.com/content/3rd_delta_edition/BIOS_Firmware_3_delta/)

The BIOS firmware must be at least the LP-BS-7-S70JR120-CN51G-E version to support the serial redirection function. For instructions on how to update the BIOS firmware, please refer to: https://docs.lattepanda.com/content/3rd_delta_edition/bios_update_BIOS_firmware/

Wiring

The RS232 DB9 has male and female connectors, and their pin definitions are shown in the diagram below:

The LattePanda 3 Delta uses the pinout of a male connector, and its pin positions and sequence are shown in the diagram below:

For RS232 DB9, usually only three pins are needed: TX, RX, and GND. Connect the TX, RX, and GND pins of the USB to RS232 Converter's DB9 interface to the RX, TX, and GND pins of the LattePanda 3 Delta's RS232 pin headers, respectively. Essentially, the TX and RX pins of the two connectors are cross-connected, as shown in the table below.

Of course, you can also use a DB9 to pin header cable to convert the RS232 pins of the LattePanda 3 Delta to a DB9 connector for easier wiring.

Specific Steps

- Ensure that the BIOS firmware version is supported; if not, please update the BIOS firmware.

- Follow the steps in the previous section to complete the Wirings.

- Connect the monitor and keyboard to the Lattepanda board. After powering on, repeatedly press the DEL key to enter the BIOS setup.

- Enable the serial redirection function in the BIOS.

 1. After booting the LattePanda 3 Delta, repeatedly press the DEL key to enter the BIOS setup.

 2. Navigate to Advanced -> Serial Port Console Redirection

 3. Set the Console Redirection option to Enabled

 4. Go to Console Redirection Setting

5. It is recommended to set Terminal Type to VT100+; set Bits Per second to 115200 for smoother display in terminal software

 6. Go to Save & Exit -> Save Changes and Exit, to save the settings and exit.

- Insert the USB to RS232 Converter into your computer, then run a terminal software like PuTTY to view and modify BIOS settings.

 1. Select Serial, input the port number of the USB to RS232 Converter (which can be checked in Device Manager) under Serial Line; set Speed to 115200; click Open.

 2. Restart your LattePanda 3 Delta board. Continuously press the DEL key on the keyboard (which is connected to the LattePanda board) to enter the BIOS setup.

 3.You will be able to see the full BIOS interface in the terminal of PuTTY. Use the arrow keys on your computer keyboard to navigate, and the BIOS interface in the terminal will change correspondingly.