[[https://www.best-microcontroller-projects.com/arduino-port-expander.html|Arduino Port扩展器]]
  * I2C Arduino 端口扩展器
  * [[https://www.best-microcontroller-projects.com/mcp23017.html|I2C MCP23017 ： Arduino Port Expander]]
  * [[https://www.best-microcontroller-projects.com/pcf8574.html|I2C PCF8574 ： Arduino Port Expander]]
  * SPI Arduino 端口扩展器
  * [[https://www.best-microcontroller-projects.com/mcp23017.html|SPI MCP23S17： Arduino Port Expander]]
  * [[https://www.best-microcontroller-projects.com/74hc595.html|SPI 74HC595 并行输出：Arduino 端口扩展器]]