The LCD and the buttons/led are driven using two MCP23008 devices throught I2C bus.
The Arduino's I2C pins used are A4 and A5 (which are the ones of the Arduino UNO).
- One MCP23008 is connected to the LCD. Its address range is 0x20 to 0x23.
- The other MCP23008 is connected to the buttons/LED. Its address range is 0x24 to 0x27
A SW library has been developed to easily use the interface functions. It is based on two libraries developed by Adafruit which are
- Adafruit LiquidCrystal
- Adafruit MCP23008 library
Both are already included in the Technoshield User Interface SW Library.