What is serial communication of microcontroller?

Microcontrollers (MCUs) have serial communication capabilities, where data is arranged in a straight line and transmitted sequentially, while parallel communication transmits 8 bits of data at a time through multiple terminals. When communicating with the string "ABC", in parallel communication, each character is transmitted simultaneously, while in serial communication, it is transmitted sequentially starting from "B", "C" to "A".

Since serial communication does not depend on the number of data bits to be transmitted, the number of terminals can be small.

In serial communication, there is UART communication that does not require a synchronization signal. Data is transmitted between a "start bit" indicating the beginning and a "stop bit" indicating the end. This is called an asynchronous (synchronous) type. These are often used in interfaces such as wireless LAN modules.

USART communication is an extension of UART and also supports synchronous communication.

USART communication is built into the microcontroller as a peripheral. In addition, RS232C, RS485, RS422, etc., which are commonly used in industrial equipment, have different signal level standards but are basically similar. Usually, they can be used as external circuits by adding a level conversion IC. Clock synchronous serial communication that requires synchronization signals includes I2C and SPI communications, which are often used in interfaces such as EEPROM.

If a UART-USB converter cable is used, we can easily operate and monitor it by connecting it to a PC and creating free serial terminal software or a dedicated application. In the process of microcontroller development, USART communication has a wide range of applications, so it is one of the functions that must be learned for beginners learning microcontrollers.