Editing Microcontroller (section)

{{Short description|Small computer on a single integrated circuit}}
{{for|a small computer on a printed circuit board|Microcomputer}}
[[File:Intel 8742 153056995.jpg|right|thumb|230px|The [[die (integrated circuit)|die]] from an [[Intel]] 8742, an 8-bit microcontroller that includes a [[Central processing unit|CPU]] running at {{nowrap|12 MHz,}} {{nowrap|128 bytes}} of [[Random-access memory|RAM]], {{nowrap|2048 bytes}} of [[EPROM]], and [[Input/output|I/O]] in the same chip]]
[[Image:Microcontrollers Atmega32 Atmega8.jpg|thumbnail|Two ATmega microcontrollers]]

A '''microcontroller''' ('''MC''', '''uC''', or '''μC''') or '''microcontroller unit''' ('''MCU''') is a small [[computer]] on a single [[integrated circuit]]. A microcontroller contains one or more [[Central processing unit|CPUs]] ([[processor core]]s) along with [[Computer memory|memory]] and programmable [[input/output]] peripherals. Program memory in the form of [[Flash memory#NOR flash|NOR flash]], [[Programmable read-only memory|OTP ROM]], or [[ferroelectric RAM]] is also often included on the chip, as well as a small amount of [[random-access memory|RAM]]. Microcontrollers are designed for [[Embedded system|embedded]] applications, in contrast to the [[microprocessor]]s used in [[personal computer]]s or other general-purpose applications consisting of various discrete chips.

In modern terminology, a microcontroller is similar to, but less sophisticated than, a [[system on a chip]] (SoC). A SoC may include a microcontroller as one of its components but usually integrates it with advanced peripherals like a [[graphics processing unit]] (GPU), a [[Wi-Fi]] module, or one or more [[coprocessor]]s.

Microcontrollers are used in [[Control system|automatically controlled]] products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, appliances, power tools, toys, and other [[embedded system]]s. By reducing the size and cost compared to a design that uses a separate [[microprocessor]], memory, and input/output devices, microcontrollers make digital control of more devices and processes practical. [[Mixed-signal integrated circuit|Mixed-signal]] microcontrollers are common, integrating analog components needed to control non-digital electronic systems. In the context of the [[internet of things|Internet of Things]], microcontrollers are an economical and popular means of [[data collection]], [[Sensor|sensing]] and [[Actuator|actuating]] the physical world as [[edge device]]s.

Some microcontrollers may use four-bit [[Word (computer architecture)|words]] and operate at frequencies as low as {{nowrap|4 kHz}} for low [[Electric energy consumption|power consumption]] (single-digit [[Watt|milliwatts]] or microwatts). They generally have the ability to retain functionality while [[Wait state|waiting]] for an [[Event-driven architecture|event]] such as a button press or other [[interrupt]]; power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts, making many of them well suited for long lasting battery applications. Other microcontrollers may serve performance-critical roles, where they may need to act more like a [[digital signal processor]] (DSP), with higher clock speeds and power consumption.