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Microcontrollers Basics: The Structure, Working Principle, and Applications

Microcontroller on board

Microcontroller on board

Source: Wikimedia Commons

Before you dive into the world of embedded electronics, you need to understand what it takes. For instance, this field involves writing your codes. And it’s almost impossible to do this if you don’t understand microcontrollers’ basics, the programming language it uses, or its fundamental programming concepts. Or else you’ll be confused about where to start and overwhelmed as well.

But, there’s good news:

This article will learn the basic things you need to get started with embedded electronics. We’ll discuss what it is, how the microcontroller works, the basic structure, and more.

Let’s get started!

What is a Microcontroller?



Source: Wikimedia Commons

Before defining the microcontroller, it’s vital to note that it differs from the microprocessor (which we’ll discuss later in the article).

That said, the microcontroller is a very large-scale integration IC. And it comprises the I/O ports, logic unit, memory, electronic computing unit, and other modules fused on a single chip. You can also refer to the device as a Single-Chip-Computer.

Additionally, the microcontroller is also an Embedded Controller. And it’s because the device alongside the supporting circuitry goes into the appliance it controls.

You can find microcontrollers in many devices or applications that display data, measure, control, store, or calculate. Interestingly, the Automobile Industry tops the list for the biggest microcontroller users. After all, vehicles need the device for engine control and regulating other systems.

Another area where microcontrollers are common is in consumer electronics. So, you can find microcontrollers in ovens, digital cameras, DVD players, etc. Test and measuring equipment also use microcontrollers, e.g., function generators, multimeters, etc.

Microcontrollers Basics– How Does the Microcontroller Work?

Typically, microcontrollers run a particular program and stick to one task. So, they work by getting input from the device that they control. Consequently, this helps the microcontrollers maintain control. And it does this by sending signals to different parts of the device.

For instance, a TV’s microcontroller works by getting input from the remote control. Then, it delivers the output on the TV screen.

The Types of microcontrollers

We have different microcontrollers based on the following categories: instruction sets, memory, and bits.

Instruction Sets

There are two categories of microcontrollers based on the instruction set configuration:


This acronym means Reduced Instruction Set Computers. It does this by reducing the clock cycle for every instruction. And it helps to lessen the working time.


This acronym represents Complex Instruction Set Computer. And it permits users to fix one instruction as an option to different simple commands.


Microcontrollers Basics--Memory Card (RAM)

Memory Card (RAM)

Source: Wikimedia Commons

In the memory configuration category, there are two types of microcontrollers:

Embedded Memory Microcontroller

This type of microcontroller usually has so many components on the chip like timers and counters, I/O ports, data memory, interrupts, etc. An example of an embedded memory microcontroller is the Intel 8051.

External Memory Microcontroller

The design of this type of microcontroller doesn’t have a program memory on its chip. An excellent example of an external memory microcontroller is the Intel 8031.


There are three types of microcontrollers in the bit configuration category:

32-Bit Microcontroller

You can find the 32-bit microcontroller in appliances that use automatic control like medical appliances, etc.

16-Bit Microcontroller

The 16-bit microcontroller is useful for high performance and accuracy applications. So, you can use this microcontroller to do logical and arithmetic operations. An excellent example of this microcontroller is the Intel 8096.

8-Bit Microcontroller

The 8-bit microcontroller is the least in this category. And you can use it to carry simple tasks like executing logical and arithmetic operations like division, subtraction, etc. Also, examples of this microcontroller are Intel 8051 and 8031.

Basic Structure of a Microcontroller

The microcontroller has three fundamental components: I/O ports, memory, and the Central Processing Unit.

Other components of this device are vital as well. But the ones mentioned above are supporting devices. So, we’ll take a close look at the primary components of a microcontroller-based on its structure.

Microcontrollers Basics– Memory

Typically, most computational systems need two types of memory: Data and Program memory. The data memory helps to keep temporary information while it carries out instructions. But the Program memory consists of the program. That is, it contains the instructions that the CPU will perform.


The System Bus is one of the least talked about components. But, it’s a vital part of the microcontroller.

It refers to a collection of connecting wires that link the CPU to other peripherals like the I/O ports and other supporting components.

Microcontrollers Basics– CPU

The CPU is like the microcontroller’s rain. And it has two parts: the CU (Control Unit) and ALU (Arithmetic Logic Unit).

So, the CPU is responsible for decoding, reading, and performing instructions to execute Data, Logic, and Arithmetic transfer operations.


The interrupts are another vital component of the microcontroller. And it has an Interrupt Handling Mechanism. Also, this component can be software-related, eternal, hardware-related, or internal.

Microcontrollers Basics– I/O Ports

The I/O refers to the Input/Output ports. This component offers the microcontroller an interface to external connections. For instance, Input devices like the keypads, switches, etc., give information from a user to the CPU. And it does this in a Binary Data form.

So, when the CPU gets the information from the input devices, it performs suitable instructions. Then, it responds via the output devices like printers, displays, LEDs, etc.

Serial Port

This component helps the microcontroller interact via serial communication. A microcontroller can only communicate with other external peripherals and devices via the serial port. And the UART is the microcontroller’s most common serial communication.


This acronym stands for Digital to Analog Converter. And it’s a circuit that changes Digital signals to Analog signals. Also, this component connects the microcontroller’s CPU and analog devices (external).


The ADC acronym stands for Analog to Digital converter. And it’s the opposite of the DAC. That is, the circuit helps to change Analog signals to Digital signals. Also, this circuit creates a connection between the external Analog Input devices and the microcontroller’s CPU.

Further, it’s crucial to note that analog devices are mostly sensors. Hence, for the CPU to understand the communication, the analog data must change to digital.

Microcontrollers Basics–Counters/Timers

The counters and timers are vital components of the microcontroller. And they are responsible for offering operations of counting external events and time delays. Also, the components offer Clock Control, Function Generation, etc.

Configuration Bits

Microcontrollers usually have a unique bit. And it’s the Configuration bits. This component helps to structure the microcontroller’s special options, which include (but aren’t restricted to):

  • Low Voltage Programming On/Off
  • Power Up Timer On/Off
  • Internal/External switchover On/Off
  • Oscillator Type
  • Fail-Safe Clock Monitor On/Off
  • Brown Out Reset On/Off
  • Watchdog Timer On/Off

Also, on a PIC microcontroller, you’ll notice configuration bits. And it’s responsible for data code protection and program code protection.

That is, the configuration bits stop external programming hardware from reading your program and data spaces. Hence, it will be difficult for others to steal your code.

Comparison Between the Microprocessor and Microcontroller

Microcontrollers Basics--Microprocessor


Source: Wikimedia Commons

Microcontrollers Basics


Source: Wikimedia Commons

The microcontroller is a computer that consists of timers, ROM, and other peripherals. Hence, you can call them mini-computers. Plus, they come in a different version. But the microprocessors are integrated circuits. And they have processing power with only a CPU inside them.

Here’s a table showing their differences:


  • Since it writes and stores instructions in the memory, the microcontroller doesn’t need complex operating systems.
  • The chip doesn’t require external interfacing of primary components like the I/O ports.
  • You can program the I/O ports.
  • Putting all the vital components reduces the area of the product, cost, and design time.


  • It doesn’t have an operating system. Hence, you have to write all the commands.
  • The microcontroller’s memory (depending on the amount) can limit the instruction that the device can perform.

Wrapping Up

In summary, the microcontroller basics explain the power of the single-chip microcomputer. Further, it comprises several peripherals that make up the device’s structure like the memory, CPU, I/O ports, Oscillatory circuits, etc. Also, manufacturers build the microcontroller into devices they control.

And each of the peripherals plays a vital role that contributes to the function of the microcontroller. What do you think about microcontrollers? Do you need help with getting the best one for your project? Please feel free to reach us.

Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.