Microcontrollers, or MCUs, are small integrated circuits used in embedded applications. These chips serve as the brain of a system or sub-system and typically contain integrated memory to run their application code and peripherals like serial ports, timers, and PWM digital outputs. Many variations also include non-volatile storage to store code when they’re unpowered.
Microcontrollers tend to have lower processing capability and use 8, 16, of 32-bit instruction sets. Their primary purpose is to automate and control devices.