Introduction to MCU GPIO Interface

Microcontrollers (MCUs) are widely used to control all types of electronic devices. MCUs consist of a CPU (central processing unit), memory, and additional circuits that implement various peripheral support functions.

    The CPU operates by reading programs and following instructions: reading data, performing calculations and comparisons, generating other operations based on the comparison results, etc. The role of memory is not only to store data, but also the program itself.

    MCUs also include circuits that implement various peripheral functions, making it easier to deploy in a variety of settings. For example, an MCU typically includes a variety of I/O (input and output) ports to facilitate the flow of signals between the CPU and external sensors and switches. It also typically includes one or more ADCs (analog/digital converters) to convert incoming analog signals to digital values, and one or more DACs (digital/analog converters) to convert digital values ​​to output analog signals. These I/O ports and converters support the use of a variety of signal types.

    One of the most commonly used peripherals of microcontrollers is the RTC (Real Time Clock), which is used to achieve accurate time measurement and time monitoring and is widely used by processes that reference or depend on time. Another common peripheral is the UART (Universal Asynchronous Receiver Transmitter), which is used to convert parallel signals to serial signals and serial signals to parallel signals.

    Important peripherals: GPIO interface

    GPIO (General Purpose Input/Output) ports handle incoming and outgoing digital signals. As an input port, it can be used to communicate ON/OFF signals received from switches or digital readings received from sensors to the CPU. As an output port, it can drive external operations based on CPU instructions and calculation results - for example, driving an LED display based on calculation results, or outputting drive signals to a motor.

    GPIO is also called a "general purpose interface" because each pin can be freely set to be used as an input or output. In early MCUs, each port was either exclusively input or exclusively output. However, GPIO is flexible. If it has 8 pins, you can set them to best suit your needs: 4 inputs and 4 outputs, or 7 inputs and 1 output, or any other combination.

    It is important to note that when programs read, write, and manipulate digital values ​​(0s and 1s), external devices typically use signal levels: low voltage and high voltage.