Button edge Events

The repository [s2.1]{https://github.com/kf5011/s2.1} uses a falling and rising edge interrupt on each of the two buttons on the base board.

1. Run the program and examine it's behaviour. (You'll need the serial-monitor to see the output from the print statements)

2. Pay close attention to when the actions occur, when the button is pressed or released.

3. Identify the input pins related to the buttons and the 5-way joystick on the shield.

4. Each pin can have an interrupt for the rising-edge and falling-edge signal, a total of 14 possible interrupts.

5. Investigate the actions of the interrupts for the base-board switches and the 5-way switch. What differences can you see?