Microcontrollers also referred to as MCUs (microcontroller units), are embedded semiconductor devices used in circuit board design. They are essentially a computer within an integrated circuit (IC). Microcontrollers are mostly used in single-function ’embedded’ applications, unlike microprocessors which are designed for general-purpose work in Personal Computers, Tablets and Smartphones. Microcontrollers are limited in their clock speed compared to microprocessors by the relative slowness of their non-volatile Flash program memory.
Microcontrollers contain single or multiple processors (sometimes referred to as CPUs), plus memory and I/O peripherals. These peripherals include timers, ADCs (analogue-to-digital converters) and DACs (digital-to-analogue converters).
Microcontrollers have a data bus width which describes the amount of data the MCU can process at a time. For example, an 8-bit microcontroller can process 8 bits at one time. Popular data bus widths include 8-bit, 16-bit and 32-bit MCUs.
MCUs come in standard chip packages with various pin counts. Package types include:
Microcontrollers often contain an ARM microprocessor core. ARM represents an architecture developed by ARM Holdings, which is used by other companies to manufacture microprocessors and other devices such as System-on-Chip (SoCs).