You will find working with GPIO very interesting! You already know from the first chapter that the GPIO pins are the configurable pins of a processor and if you will closely see the RasPi board, the GPIO functionality is brought out on board pin-out header from the processor in such a way that the GPIO status can be changed and also be read during the runtime. That is what we are going to do in this section. While programming, you will notice that the RasPi's GPIO has two modes: board mode and BCM mode. Board mode can be seen as the pin numbers physically seen on the board, which are internally connected to the processor. As the processor has numerous pins and GPIOs available, the processor pin number and the board header pin number will always be different. For example, the processor has internally assigned the GPIO 17 designation on its own pin, while on the RasPi board, a connector will have number 11 of the pin. Let's see the available GPIO pins and their...