A microcontroller (or MCU for "microcontroller unit) is a small integrated circuit that controls an electronic device. It is similar to a microprocessor but includes memory and other integrated components.

A typical microcontroller includes the following elements:

  1. CPU - ranging from a simple 4-bit processor to a full-blown 64-bit processor
  2. RAM - high-speed volatile memory used to store data temporarily
  3. Flash memory - a type of non-volatile memory used to store data with or without electrical power
  4. I/O interface - serial ports or other connectors for peripheral devices
  5. Wireless communications - transmitters or receivers for sending and receiving wireless signals

Some MCUs are several inches long and wide. Others are extremely small, with a length and width of less than one millimeter. Because microcontrollers are integrated circuits, most are relatively flat. Below are examples of different types of microcontrollers:

  1. an image processor on a digital camera
  2. a digital-to-analog converter (DAC) in a powered speaker
  3. a temperature sensor in a washing machine or dryer
  4. a Wi-Fi transmitter in a smart appliance
  5. a motion tracker in a smartwatch

Nearly all electronic devices include microcontrollers. Many include multiple MCUs that operate in tandem. An automobile, for example, may contain dozens of microcontrollers for sensors, communication, and user interface functions.

Updated August 19, 2021

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