Digital Input and Output

Abstract

Previous chapters focused on the inner working principles of the STM32F4 microcontroller. In order to use the microcontroller properly, it should interact with the outside world. To do so, we will introduce interfacing digital input and output (digital I/O) to and from the microcontroller in this chapter. Peripheral units dedicated for this operation are called general-purpose input and output (GPIO) pins. These will form a bridge between code-based bit values (logic level 0 or 1) and voltage levels to be fed or received from the outside world. Therefore, we will first explore the bit representation in terms of voltage values. In other words, we will show how the logic level 0 or 1 can be represented in voltage level. Afterward, we will deal with interfacing these voltage levels with the microcontroller. Here, we will handle different structures such as interfacing the microcontroller with inputs having a high voltage value or output to loads requiring high current or voltage. We will also focus on digital I/O setup within the STM32F4 microcontroller followed by its usage. We will consider C, C++, and MicroPython languages for this purpose. As the end of the chapter application, we will start with digital input and output operations in the robot vacuum cleaner to be developed throughout the book.