Serial Communication

Hardware Setup

• Solder a second serial port on the development board
• Four female-to-female jumper wires
• RS232-to-serial data cable / male-to-male RS232 data cable
• TTL-to-RS232 chip

Wiring notes: Connect the development board to the chip with jumper wires. The short side of the board has “串口” (Serial) printed on it; on the serial side, the topmost pin is ground, the third pin from top is power, and pins 2 & 4 are data lines. If the test fails, swap the two data lines.

• Connect the chip to the PC / scale via the data cable

Serial Parameter Configuration

Before communication, confirm the serial parameters of the scale (or host) match the development board:

• Baud rate
• Data bits
• Parity
• Stop bits

In the board’s Settings → Hardware Settings, select Serial as the communication method and configure the parameters.

Data Exchange Examples

1. Configure serial parameters on the board, load and enable the corresponding Lua script
2. Insert the corresponding register into the text/barcode object
3. Host sends data frames ending with \r\n
4. When data reaches the register, the canvas object content updates

Scale Integration

1. Configure baud rate and protocol on the scale — must match the board’s serial configuration

2. Enable the weight acquisition script (e.g., getWeight.lua); if not present, install it from a USB drive

3. Determine the register number and insert it into the text/barcode object
4. When the weight data arrives, the object content changes — success

PC Integration

1. Download software that supports serial data transfer (e.g., Bittly on Linux)

2. Set serial protocol, PC serial port, and baud rate; then configure data bits, parity, stop bits
3. Send text content ending with \r\n; objects bound to registers update
4. After enabling the print feedback feature, a frame ending with \r\n containing the print counter is returned after each print