As we discussed in Chapter 1, Getting Started with BeagleBone, BeagleBone boards have GPIO pin headers on either side of the board. In this section, we will be discussing what these GPIOs are and how we can use them to interface external electronic components to the board.

The following figure shows the GPIOs available and the pin mapping of each of them. This pin mapping or, in general, the names assigned to these pins will be helpful for us while accessing them from the software running on the operating system. You will see this in detail at the end of the chapter, when we will be accessing the GPIO from python:

So, these GPIOs are ports which can act either as input or output from our definition from software running on the operating system. There are several methods to define these pins as input and output, as well as to change the state of these pins when defined as outputs and read the state when defined as inputs. In this book, as we will be using python as the primary programming...