What Is a Microcontroller?

Countless microcontrollers are deployed in the IoT. Here are a few facts about the MCU that everyone should know.

Much like they say about spiders, you are likely always within 6ʹ of a microcontroller (MCU). That’s because millions of microcontrollers are deployed throughout the Internet of Things. Regrettably, few nonengineers know much about these remarkable, ubiquitous devices. Here are a few key facts about microcontrollers that everyone should know.

The Mighty Microcontroller

What is a microcontroller? What makes a microcontroller different than a microprocessor (MPU)? How do designers use MCUs? Are Arduinos and Raspberry Pis MCUs?

Electrical engineers know the answers to these questions because they implement microcontrollers in the products they develop for virtually every industry from aerospace to healthcare. Unfortunately, many nontechnical executives, marketing managers, sales reps, and software developers are unfamiliar with microcontroller technology. Nonengineers often confuse the terms microcontroller, microprocessor, system on a chip, microchip, and IC – and they sometimes use them interchangeably. To address the issue, I’ve put together a list of five essential things everyone should know about microcontrollers. If you’re a professional engineer or pro maker, you can skip this article — just be sure to share it with your nontechnical colleagues.

A controller is not the same as a processor. A microcontroller is a computer on a single chip that includes a processor core, memory, and I/O peripherals, and it is typically used for a specific function in an embedded system. For instance, you can use microcontrollers to operate sensors, record data, control LEDs, communicate with other microcontrollers, and much more. A microcontroller’s memory, I/O ports, and ROM/RAM are located within the chip. A microprocessor’s peripherals are external to it. So, ROM/RAM, serial interface, timers, and I/O ports are connected to a microprocessor.
Microcontrollers are super-focused. Microcontrollers are application-specific and used for predefined tasks. For instance, you can use a microcontroller to control a motor in a robotic system. In contrast, microprocessors are used for applications that require intense processing, such as running large graphics programs on laptops. Basically, you don’t use an Intel CORE i5 to perform a microcontroller’s job.
Microcontrollers can do a lot with very little. A microcontroller does not offer the high speed and large memory of a microprocessor. Think of it. A microcontroller has an application-specific task to manage, and thus doesn't require breathtaking speed and a ton of memory, while a microprocessor will be called on to run complicated, resource-intensive tasks. An MCU’s clock speed might be 300 MHz compared to a processor’s speed of 4 GHz.
8 bits is not dead. In the early 2000s, some tech journalists proclaimed “8 bits is dead” due to the proliferation of exciting new 32-bit technology. Things sure have changed. With the explosion of the IoT, low-cost 8-bit microcontrollers are in high demand for use in a wide variety of applications, including automotive control systems, aerospace applications, industrial automation, wearable electronic devices, robotics, and medical equipment.
Microcontrollers are everywhere. The IoT comprises billions of 8-, 16-, and 32-bit devices. Simply put, microcontrollers are used everywhere: automobiles, planes, home appliances, toys, surveillance systems, industrial plants, and medical devices. Remember the old saying that you are always 6ʹ away from a spider? In this IoT era, it’s safe to assume you have several microcontrollers your vicinity right now.

Maxim's MAX78000 microcontroller up close

MCU Resources

Elektor engineers and editors are regularly writing about micrcontrollers and microcontroller-related technologies. Check out these resources for additonal information.