Code: Select all
#include "Adafruit_MCP23017.h"
The example sketches from the Adafruit_MCP23017 library show you how to handle the basic object creation and initialization:
https://github.com/adafruit/Adafruit-MC ... button.pde
WRT the physical connections, I just looked for a tutorial and only found one for the Raspberry Pi. Post a photo of how you have things hooked up and we'll make sure that part is correct.