What is a Microcontroller-A Complete Guide

Whether you’re driving your car, reading this on your computer (or on your smartphone/tablet), or brewing a cup of coffee on your coffee maker, microcontrollers are all around you. Microcontrollers are a big aspect of the modern world, with the Internet of Things continuously growing and data being collected on a regular basis.

This Blog provides an overview of the microcontroller, as well as  Microcontroller architecture, Types,  Advantages, Disadvantages, and Applications.

What is a Microcontroller?

 A microcontroller is a single-chip computer that incorporates all of the functions found in a microprocessor. It has a high concentration of on-chip facilities such as RAM, ROM, I/O ports, timers, serial ports, clock circuits, and interrupts to support various applications. Microcontrollers are utilized in remote controls, vehicle engine control systems, medical devices, power tools, office machinery, toys, and other embedded systems, among other things. 

Generally, a microcontroller collects data, processes it, and then performs a specific action based on the data collected. Microcontrollers typically operate at lower speeds, in the 1MHz to 200 MHz range, and must be engineered to consume less power because they are embedded inside other devices that may demand more power elsewhere.

History of Microcontrollers

Microcontrollers were first invented in the early 1970s, becoming commercially available in 1974. Gary Boone, an engineer from Texas Instruments, is credited with inventing the initial concept of the modern microcontroller. Coincidentally, the first microprocessors were also being developed at this time

Elements of a Microcontroller

  • Central Processing Unit — The brain of a microcontroller is referred to as the CPU. The CPU is the device that is used to fetch data, decode it, and then properly execute the operation. All of the microcontroller’s components are connected into a single system with the help of the CPU. The CPU decodes the instructions retrieved from the programmable memory.
  • Memory — In a microcontroller, the memory chip functions in the same way as the CPU. All programs and data are stored on a memory chip. For the storage of program source codes, microcontrollers are equipped with a specified amount of ROM or RAM (EPROM, EEPROM, etc.) or flash memory. A microcontroller has two main memory types:
    • Program memory is where the CPU keeps long-term information about the instructions it executes. Program memory is non-volatile memory, which means it may store data indefinitely without the need for a power source.
    • Data memory is needed to store temporary data while the instructions are being executed. Data memory is volatile, which means that the data it stores is only transient and is only kept if the device is powered up.
  • Peripheral I/O — The processor’s input and output devices serve as its interface to the outside world. The input ports take in information and transfer it to the processor as binary data. The processor receives this information and transmits the required instructions to output devices, which carry out duties that are not controlled by the microcontroller.

While the processor, memory, and I/O peripherals are the most important components of a microprocessor, other components are typically incorporated as well. Supporting components that interface with the memory and CPU is referred to as I/O peripherals. Peripherals are a broad category that includes a wide range of supporting components. An I/O peripheral is essential to a microprocessor since it is the mechanism by which the processor communicates with the outside world.

Other supporting elements of a microcontroller include:

  • Analog to Digital Converter (ADC) — To convert analog signals to digital signals, an ADC is used. For ADC to work, the input signals must be analog. Digital signal generation can be used for a variety of digital applications (such as measurement gadgets).
  • Digital to Analog Converter (DAC) — The inverse function of an ADC is a DAC, which allows the microcontroller’s CPU to send its outgoing signals to external analog components.
  • System bus — The system bus is the connective wire that links all components of the microcontroller together.
  • Serial port — The serial port is one example of an I/O port that allows the microcontroller to connect to external components. It has a similar function to a USB or a parallel port but differs in the way it exchanges bits.
  • Timers– One or more timers or counters could be incorporated into a microcontroller. All counting and timing actions within a microcontroller are controlled by timers and counters. External pulses are counted using timers. Pulse creation, clock functions, frequency measuring, modulations, oscillations, and other actions are done by timers.

Microcontroller Architecture

Despite the fact that there are only three basic types of microcontrollers, there are several MCU manufacturer brands and architectures to choose from.

The following are some of the most prevalent names that users should be aware of:

  • ARM core processors (many vendors supply ARM microcontrollers and related components including ARM Cortex-M cores)
  • Microchip Technology Atmel AVR microcontrollers (8-bit), AVR 32 (32-bit), and AT91SAM (32-bit)
  • Microchip Technology PIC microcontrollers (8-bit PIC16, PIC18, 16-bit dsPIC33, PIC24, 32-bit PIC32)
  • Freescale ColdFire (32-bit) and S08 (8-bit)
  • Intel 8051 microcontrollers
  • PowerPC ISE
  • Renesas Electronics (RL78 16-bit MCU, RX 32-bit MCU, SuperH, V850 32-bit MCU, H8, R8C 16-bit MCU)
  • Silicon Laboratories Pipelined 8-bit 8051 microcontrollers and mixed-signal ARM-based 32-bit microcontrollers
  • Texas Instruments TI MSP430 (16-bit), MSP432 (32-bit), C2000 (32-bit)
  • Toshiba TLCS-870 (8-bit and 16-bit)
  • CISC and RISC (also RISC-V)

What Size is a Small Microcontroller?

Microcontrollers are tiny electronic components that are designed to be as small as possible without compromising performance. Many common MCUs have heights ranging from 0.5mm to 4.95mm and lengths ranging from 4mm to 35.56mm. It should be noted, however, that this can vary greatly depending on a variety of other aspects and requirements. A height of 0.15mm and a length of 1.06mm are among the smallest microcontroller dimensions.

How to choose the Best Microcontrollers?

The optimal microcontroller for your project will ultimately be determined by your needs. When choosing a microcontroller device, you should consider numerous important variables, including:

  • Temperature tolerance
  • Architecture
  • Memory capacity
  • Price and cost-effectiveness
  • Efficiency (performance vs power consumption)
  • Security
  • Brand or manufacturer
  • Processing power
  • Interface
  • Maximum frequency (MHz)


Types of Microcontrollers

Microcontrollers are classified based on their memory, architecture, bits, and instruction sets. The following is a list of their various types. −

  • Bit

The microcontroller is further classified into three kinds based on bit configuration.

  • 8-bit microcontrollers: These are used to perform mathematical and logical operations such as addition, subtraction, multiplication, division, and so on. The Intel 8031 and 8051, for example, are 8-bit microcontrollers.
  • 16-bit microcontroller:  This type of microcontroller is used to execute arithmetic and logical tasks that demand greater precision and performance. The Intel 8096, for example, is a 16-bit microcontroller.
  • 32-bit microcontrollers: They are commonly found in automatically operated appliances such as automatic operational machines, medical devices, and so on.
  • Memory

Based on the memory configuration, the microcontroller is further divided into two categories.

  • External memory microcontroller − External memory microcontrollers are microcontrollers that do not have a program memory built into the chip. As a result, it’s known as an external memory microcontroller. For instance, consider the Intel 8031 microcontroller.
  • Embedded memory microcontroller − This type of microcontroller is designed in such a way that the microcontroller has all programs and data memory, counters and timers interrupt, and I/O ports are embedded on the chip. For example Intel 8051 microcontroller.
  • Instruction Set

Based on the instruction set configuration, the microcontroller is further divided into two categories.

  • CISC − The acronym CISC refers to a computer with a complicated instruction set. It allows the user to replace multiple basic instructions with a single one.
  • RISC − RISC stands for Reduced Instruction Set Computers. It reduces the operational time by shortening the clock cycle per instruction.

Advantages of the microcontroller :

  • Low time required for performing the operation.
  • It is easy to use, and troubleshooting and system maintenance is straightforward.
  • At an equivalent time, many tasks are often performed therefore the human effect is often saved.
  • The processor chip is extremely small and adaptability occurs.
  • The cost and size of the system are less.
  • The microcontroller is straightforward to interface with additional RAM, ROM, and I/O port.
  • Once the microcontroller is programmed then it can’t be reprogrammed.
  • If the digital parts were not present it will look like a microcomputer.
  • It is easy to use, and troubleshooting and system maintenance is straightforward.

Disadvantages of the microcontroller :

  • It is generally utilized in micro equipment.
  • It has a complex structure.
  • Microcontrollers cannot interface with a better power device directly.
  • The number of executions is limited.
  • As every Microcontroller does not have analog I/O so there are issues related.

Applications of Microcontrollers

Microcontrollers are widely used in various different devices such as −

  • Light sensing and controlling devices like LED.
  • Temperature sensing and controlling devices like microwave ovens, and chimneys.
  • Fire detection and safety devices like Fire alarms.
  • Measuring devices like Volt Meter.

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