What’s the Difference Between Microprocessors and Microcontrollers?

Microprocessors and microcontrollers are centralized computer chips that provide intelligence to personal computers and electronic devices. They're built with semiconductor integrated circuits and share certain internal parts. 

Integrated circuit

Both microprocessors and microcontrollers are semiconductor components built on an integrated circuit. An integrated circuit is a very tiny square or rectangular chip that contains thousands or even millions of electronic components. Integrated circuits allow engineers to reduce the size of electronic circuits.

CPU

Both microprocessors and microcontrollers have a CPU. A CPU is the centralized part of the computer chip that processes instructions provided by applications or firmware. The CPU also has a special arithmetic-logic unit (ALU) module. An ALU calculates mathematical values and evaluates logic problems based on computer instructions. 

Registers

Registers are memory modules that the CPU uses for processing. The CPU temporarily stores instructions or binary data before, during, and after they're processed. Both microprocessors and microcontrollers are built with internal registers, although microcontrollers often have more registers than microcontrollers.

Microprocessors support versatile computing operations in personal computers and enterprise servers. Meanwhile, microcontrollers allow embedded systems to analyze and respond to inputs in real-time.

When engineers develop systems with microprocessors and microcontrollers, they're mindful of differences like these.

Clock speed

Microprocessors provide high-speed and robust computing capacities for varying applications. A modern computer processor operates in the range of gigahertz (GHz). This allows a computer system to perform complex mathematical calculations and return the results promptly. 

While the microcontroller's speed has increased throughout the decades, it's much less than the microprocessor's processing speed. Depending on its purpose, a microcontroller's clock speed ranges between kilohertz (kHz) to hundreds of megahertz (MHz). Despite the lower speed range, a microcontroller can operate optimally within its dedicated scope of application.

Circuit size

A microprocessor cannot operate on its own. It relies on external parts, such as communication chips, I/O ports, RAM, and ROM, to form a complete computing system. Therefore, a microprocessor-based circuit consists of an address and data bus connecting many peripherals and memory chips. Even with advancements in printed circuit board (PCB) technologies, a microprocessor system requires considerable space.

The microcontroller, however, provides a space-saving design with a simpler circuit. Most of the additional components a microprocessor-based system needs are readily available on the same chip. Rather than using individually separated components, engineers use a single microcontroller when designing electronic devices. This allows more space on the electronic circuit board, which allows engineers to produce compact systems. 

Power consumption

Microprocessors often run at a higher speed than microcontrollers and consume more power, so they require an external power supply. Likewise, a computing system based on a microprocessor unit has a higher total power consumption because of the large number of additional components. 

Meanwhile, microcontrollers are designed to operate efficiently with minimal power. Moreover, most microcontrollers have power-saving features, which microprocessors lack.

For example, a microcontroller can activate the power-saving mode and consumes limited power when not processing data. Microcontrollers can also turn off internal peripherals not in use to save power. This makes microcontrollers ideal for building a dedicated low-power application that runs on stored power.

Operating system

In practical applications, microprocessors require an operating system to provide the appropriate functionalities. Without an operating system, users would have to instruct the microprocessor in assembly or binary language.

Meanwhile, microcontrollers don't require an operating system to run. There are, however, specific operating systems that help mid- and high-range microcontrollers to operate more efficiently. 

Connectivity

Microprocessors handle more diverse communication technologies than microcontrollers. For example, a microprocessor processes high-speed USB 3.0 or Gigabit Ethernet data without a secondary processor.

However, most microcontrollers need a special processor for high-speed data connectivity. 

Cost

A microprocessor integrated circuit only consists of the CPU, arithmetic-logic unit (ALU), and registers, which reduces the per-unit manufacturing cost. Meanwhile, a single microcontroller has a more complex internal architecture and is generally more expensive than a microprocessor.

However, a microprocessor-based system is more expensive as it requires additional components. In contrast, a microcontroller is self-sufficient for its chosen application.

The microcontroller requires fewer additional components, which results in cheaper microcontroller-based systems. For example, an air conditioner's circuit board with a microcontroller costs less than a computer motherboard with microprocessors. 

	Microprocessor	Microcontroller
Memory	Requires external memory and data storage.	On-chip memory modules (ROM, RAM).
Peripherals	Needs additional parts. Connect with the external bus.	On-chip peripherals (timers, I/O ports, signal converter).
Computational capacity	Capable of complex computing tasks.	Limited to specific application logic.
Clock speed	Very fast. GHz range.	Fast but slower than microprocessors. kHz to MHz range.
Power consumption	High power consumption. No power saving mode.	Consumes minimal power. Built-in power saving modes.
Operating system	Requires operating systems.	Operating system is optional for some microcontrollers.
Connectivity	Handles high-speed data transfer. Supports USB 3.0 and Gigabit Ethernet.	Supports low to moderate speed communication. Serial Peripheral Interface (SPI) and I²C. Universal asynchronous receiver-transmitter (UART).
Cost	Expensive because of the additional components.	Cheaper because a single integrated circuit provides multiple functionalities.
Use case	For generic computing, or systems requiring robust computational capacity.	For compact systems, battery-powered, or logic processing devices.