In many cases, circuits are required to use several digital signals as input or output. In these cases we need to know what they are expecting and handle it appropriately. This usually takes the form of a driver.

In this section we will be exploring briefly some of those cases, such as a DC motor controller that allows us to select the direction of two motors and a stepper motor controller.

We will also take a look at other non standard uses of GPIO that require special handling, such as an ultrasonic distance sensor and an LCD numeric display.

With all these, you will get a general idea of the type of peripherals that can be controlled using GPIO and the different ways they work.