Microcontroller units (MCUs) and microprocessor units (MPUs) are two kinds of integrated circuits that, while similar in certain ways, are very different in many others. Replacing antiquated multi-component central processing units (CPUs) with separate logic units, these single-chip processors are both extremely valuable in the continued development of computing technology. However, microcontrollers and microprocessors differ significantly in component structure, chip architecture, performance capabilities and application.
The key difference between these two units is that microcontrollers combine all the necessary elements of a microcomputer system onto a single piece of hardware. Microcontrollers do not require additional peripherals or complex operating systems to function, while microprocessors do. Both circuits contain CPUs, however, microcontrollers also integrate memory, input/output (I/O) components and other varied peripherals.
Cost-effective and small-in-size, low-power microcontrollers are optimized for all-in-one functionality. As a result, these units are best used for specific applications like automotive infotainment systems and Internet-of-Things (IoT) devices.
Conversely, general-purpose microprocessors are typically more powerful and are designed to be supported by specialized hardware for increased performance in demanding applications like personal computing and graphics processing.
On a hardware level, microprocessors are based on the “classical” von Neumann architecture. This consists of a CPU with both an arithmetic logic unit (ALU) and processor registers (small amounts of fast memory storage for quick data access), a control unit, memory for data and instructions, external memory for mass storage, and I/O mechanisms. This methodology uses the same set of interconnecting wires (known as a bus) to both transmit instructions and perform operations. Microprocessors cannot perform these actions simultaneously, yet modern devices use various mitigation techniques to avoid data bottlenecks.
On the other hand, microcontrollers use the more complex Harvard architecture, which has one dedicated set of data buses and address buses for reading and writing data to memory, and another set to fetch instructions for performing operations. Since the CPU can both read an instruction and access data memory at the same time, the Harvard architecture can perform basic operations faster.
The Harvard architecture excels at real-time and high-speed computing tasks. However, the unified data and instructions memory space of the simplified von Neumann architecture results in improved reliability and scalability. For this reason, von Neumann-based microprocessors are favored for more demanding tasks such as high-performance computing (HPC) and gaming, while microcontrollers are typically used to handle fast signal processing.
Essentially, a microcontroller is a small computer on a single chip, containing a processor core (or cores), operational memory (RAM) and electrically erasable programmable read-only memory (EEPROM) for program memory. Optimized to function as standalone units, microcontroller integrations improve real-time signal processing and make these compact units ideal for controlling specific tasks or duties within embedded systems.
Lightweight, small and requiring comparatively low power, microcontrollers are ideal for battery-operated electronic devices like smartphones, smartwatches and other wearables. They are also a favorite among hobbyists. Consumer-grade programmable microcontrollers, such as those made by Arduino or the Raspberry Pi, can be easily configured in programming languages like C, C++ and Python, commonly used across Windows, Linux and MacOS operating systems. While accessible to even beginner developers, microcontrollers are also frequently applied in a wide range of professional and industrial use cases, including industrial automation, transportation safety systems and prototyping.
Responding to a custom chip request from a Japanese calculator manufacturer, Texas Instruments engineers Gary Boone and Michael Cochran are credited with creating the first microcontroller in 1971. A breakthrough in circuitry technology, the following years have produced myriad improvements and iterations from manufacturers like Intel, NXP and Arm.
The following are some of the more common types of microcontrollers:
Microprocessors are the predominant type of computer processor, integrating all the required components of a CPU into a single circuit. MPUs combine the arithmetic, logic and control units of antiquated CPU computer systems into a single multipurpose, clock-driven and register-based piece of hardware. This integrated design improves reliability by reducing potential points of failure. While microprocessors do not contain on-chip program memory, they are optimized for demanding general-purpose use and designed to support and be supported by specialized computer peripherals.
Modern microprocessors combine millions of small transistors, resistors and diodes assembled on a semiconductor material to create the key components of a CPU.
Versatile microprocessors can be found in a wide variety of applications, while specialized units are commonly employed for specific tasks requiring high-power processing. Ranging in power, performance, size, energy consumption and many other aspects, the following are some of the main types of microprocessors:
Microcontrollers and microprocessors are capable of performing some of the same tasks. However, depending on application requirements, each has their own unique strengths and weaknesses. The integrated features of a microcontroller, including power-saving modes for low power consumption, make it ideal for most embedded systems.
However, in circumstances requiring complex computations or higher processing power, microprocessors are a better choice, but the added performance and flexibility come at the cost of higher power consumption, and a higher price tag. These features make microprocessors a go-to for personal computers and industrial supercomputers.
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