What is a Microcontroller,Types, Applications, and How does it Work?

Microcontrollers are a huge part of today’s world. Everywhere you see microcontrollers are present in various forms whether driving a car, on any computer gadgets, also making a coffee with a coffee machine. As technology increases, the way of working also develops. Let’s start with the microcontroller.

What is a Microcontroller? 

A microcontroller also called MCUs or Microcontroller Unit is a single integrated circuit (IC) that is used for a specific application and designed to implement certain tasks.

Products and devices that have been automatically controlled in certain situations, like appliances, power tools, automobile engine control systems, medical equipment, high-end consumer electronics, rugged industrial devices, and computers are great examples, but microcontrollers reach much higher than these applications.

Essentially, a microcontroller works to gather input, process the information, and output a particular action based on the information gathered.

Microcontrollers or MCUs can operate at lower speeds, for example, it can operate at around in 1MHz to 200 MHz of range, and is designed to consume less power because they’re embedded inside the other devices, which have greater power consumptions in other areas.

What are the elements of a microcontroller? 

A microcontroller can be seen as a small computer, and this is often due to the essential elements inside it. The elements of microcontrollers are:

• The Central Processing Unit (CPU)
• The Random-Access Memory (RAM)
• The Read-Only Memory (ROM)
• The Input/Output Ports (I/O Ports)
• Internal Oscillator
• The Electrical Erasable Programmable Read-Only Memory (EEPROM)

1. Central Processing Unit (CPU): It is essentially known as the brain of the microcomputer. This element of the microcontroller is a microprocessor that controls and monitors all the processes taking place inside the microcontroller unit (MCU). It’s responsible for the reading and execution of all arithmetic and mathematical functions that have been performed.

2. Random-Access Memory (RAM): It is a temporary storage memory that stores information only when the power is on. It helps to run and calculate the programs which the MCU is told to execute. It is continually overwritten while in use.

3. Read-Only Memory (ROM): It is a pre-written permanent storage memory that can work even when the power is off. It essentially instructs the microcontroller on how to execute its calculation and programs when asked.

4. Input/Output Ports (I/O Ports): The I/O ports consist of one or more communications ports, typically in the form of connective pins. They permit the MCU to be connected to other components and circuits for the flow of input/output data signals and power supply.

5. Internal Oscillator: Also known as the main timer of the MCU. The Internal Oscillator functions as the microcontroller’s core clock and controls the execution rhythms of its internal processes. Similarly, any other kind of timer keeps track of your time because it elapses during a given process, and helps the MCU to start and end specific functions at specified intervals.

You can read also: What is an Amplifier and How it Works?

6. The Electrical Erasable Programmable Read-Only Memory (EEPROM): It is a kind of non-volatile memory used by MCU. Electrical Erasable Programmable Read-Only Memory stores amounts of data and information by allowing individual bytes to be erased and reprogrammed.

Other supporting elements include:

1. Analog to Digital Converter (ADC): This is a single used to convert analog signals to digital signals. It permits the processor of the MCU to interface with external analog devices, for example – sensors. It can be used for various digital applications, e.g. measurement devices.

2. Digital to Analog Converter (DAC): This is the reverse of ADC that means converts digital signals to analog signals and permits the processor of the MCU to communicate its outgoing signals to external analog components. It is usually used for controlling analog devices like DC motors, various drives, etc.

 3. System bus: It is a connective wire that connects all the components of the microcontroller.

 4. Serial Port: It is an example of I/O ports that permits the microcontroller to connect to external components. It is similar to USB but differs in the way it exchanges bits. 

How Microcontroller do works?

A microcontroller is embedded inside a system to regulate a singular function in a device. It does regulate by interpreting data it receives from its Input-Output peripherals using its central processor.

It stores temporary data and the temporary information received by a microcontroller is stored in its data memory, where the processor can access it and uses the stored instructions in its program memory to convert it into normal language and apply the incoming data. Then it uses its I/O peripherals to communicate and apply the suitable action.

Microcontrollers or MCUs are used in a wide range of systems and devices. Many devices often used multiple microcontrollers that work together in one device to handle their respective tasks.

For example, a car might consist of many microcontrollers that have the power to control various individual systems within, like the anti-lock braking system, fuel injection system, traction control, or suspension control. In this system, all the microcontrollers communicate with each other to take the proper actions.

Some other microcontrollers may communicate with a more complex central computer within the car, and others may communicate with other microcontrollers only. They can send and receive data by using their I/O peripherals and process that data to perform their designated tasks. 

Types of microcontrollers 

There are various types of microcontrollers on different bases:

Based on width-

• Bus-width: It generally refers to the parallel lines that connect the various components. Its function is to transmit data between CPU, Memory, and Input/Output Ports. Microcontrollers contain three types of buses inside it: data bus, address bus, and control bus. It is divided into three types- 8,16, 32 bits microcontrollers. 

• 8-bits Microcontroller: The bus width of such microcontrollers is 8 bit which means 1 byte wide long. It means it can transfer & process the information of 8 bits in a single cycle. The main hindrance of it is, it poses is in the mathematical operations because its ALU (arithmetic logic unit) is also an 8-bit.

To process outsized data for example 16 bit, it uses multiple cycles to finish an easy mathematical function. It results in poor performance of the general logic circuit. Common examples of 8- bits microcontrollers are Intel 8031/8051 and PIC1x. 

• 16-bit Microcontroller: The bus width of such a microcontroller is 16 bits that means 2 bytes wide long. It can transfer & process information of 16 bits in a single cycle. Its 16-bit arithmetic ALU is very efficient in its performance as compared to the 8-bit microcontroller.

And its 16-bit timer provides a wide range of 0x0000 (0) to 0xFFFF (65535) which provides the most effective accuracy per cost for any application or project that requires Timer functions. Some examples of it are 8051XA, PIC2x, Intel 8096, etc. 

• 32-bit Microcontroller: A 32-bit microcontroller contains a bus width of 32 bits which is 4 bytes long. The performance & accuracy of such microcontrollers is higher than any other microcontrollers but they’re a bit expensive & consume lots of power.

It can even support multiple peripherals required in any embedded system projects or applications like Universal Serial Bus (USB), Ethernet, Universal Asynchronous Receiver-Transmitter devices (UARTS), and a Controller Area Network (CAN) bus. Some common examples of 32-bit microcontrollers are Intel/Atmel 251 family, and PIC3x, etc. 

You can read also: What is Integrated Circuit: Types, Uses, & Applications of Integrated Circuit?

Based on Memory-

• Embedded Memory Microcontroller: Embedded memory means all the memory blocks and modules are in a single package. This functional block includes program & data memory, Timers & counters, interrupts, etc. Memory blocks are fixed and can not be expandable but in microcontrollers, ROM can extend its memory. 

• External Memory Microcontroller: This kind of microcontroller doesn’t have one among the essential memory blocks inside its chip & it has to be connected externally to function properly. The use of external modules increases the dimensions of the overall device. 

Based on Instruction Set Architecture-

• CISC (Complex Instruction Set Computer): In this kind of microcontroller, the CPU is designed to execute one or single complex command. It can execute multiple instructions by using a single instruction. It has a small-sized program and that is its advantage. But because of the large size of its instruction set with many addressing modes, it takes a multiple machine cycle to execute & result in a long time to perform. 

• RISC (Reduced Instruction Set Computers): In this kind of microcontroller, the CPU is designed to execute small and simple complex commands. It takes only one machine to execute a single instruction hence, the instruction can be reduced to execute complex instructions.

 Based on Microcontroller Architecture-

• Harvard Architecture Microcontroller: It is a type of microcontroller that has complete instruction in one machine cycle. It has two separate bus lines and separate memory storage for program code (instructions), the data, program memory & the data memory respectively. Its cost is higher due to its complex design. 

• Von Neumann (or Princeton) Architecture Microcontroller: It uses single memory for the program and data storage. It is a widely used architecture in various computers, desktops, and laptops. It required two machine cycles to complete an instruction. Its cost is very low as compared to Harvard architecture because it uses a single bus and its design is also simple. 

Various Other Types of Microcontrollers used are-

• PIC Microcontroller: Features of PIC Microcontroller are-
  • No internal oscillator
  • 40 pin IC in DIP packaging with 33 pins available for I/O
  • Uses external clock up to 20 MHz as there is no internal clock
  • Smaller instructions set of 35
  • Operating voltage ranges from 4.2v to 5.5v. 

• 8051 Microcontroller: Features of 8051 Microcontroller are-
  • 8bit microcontroller available in 40 pin DIP
  • 4Kb on-chip programmable ROM for storing program code
  • 128 bytes on-chip RAM for temporary data storage
  • 40 pin IC in DIP packaging with 32 pins available for I/O 

• AVR Microcontroller: Features of AVR Microcontroller are-
  • Having an internal oscillator of 8MHz
  • 1Kb on-chip programmable ROM for storing program code
  • 32Kb on-chip RAM for temporary data storage
  • 4 PWM channels for generating pulses
  • It contains three timers which include two 8-bit timers & one 16-bit timer. 

• ARM Microcontroller: Features of ARM Microcontroller are-
  • 32-bit RISC processor
  • energy efficient having higher performance
  • Cortex M0 processor that offers low speed at low cost
  • Based on Harvard architecture 

• RENESAS Microcontroller: Features of RENESAS Microcontroller are-
  • Based on CISC Harvard architecture
  • 8-bit & 16-bit microcontroller whereas RX is a 32-bit microcontroller
  • Low power microcontroller is RL78 while RX offers high performance & efficiency
  • RX family RAM ranges in the form of 2KB to 128KB 

Features/Advantages of Microcontrollers 

The features of microcontrollers are:

• Microcontrollers may act as a microcomputer that does not have any digital parts.
• Due to the higher integration inside the system, microcontrollers reduce the cost and size of the system.
• Instruction cycle timer.
• Microcontroller usage is easy, and simple to troubleshoot and system maintaining.
• Easily interface additional RAM, ROM, I/O ports.
• It required less time for performing operations.

Disadvantages of Microcontrollers 

The disadvantages of Microcontrollers are:

• Microcontrollers have a more complex architecture than microprocessors.
• It can only perform a limited number of executions simultaneously.
• It is mostly used in micro-equipments which are hard to operate.
• It cannot interface high-power devices directly because of its slower speed. 

Examples of Microcontroller 

Here is the list of common microcontrollers that are widely used.

• Altera
• Analog Devices
• Atmel
• Espressif Systems
• Freescale Semiconductor
• Cypress Semiconductor
• ELAN Microelectronics Corp
• EPSON Semiconductor
• Hyperstone
• Holtek
• Fujitsu
• Infineon
• Intel
• Lattice Semiconductor
• Parallax
• Rabbit Semiconductor
• Renesas Electronics
• Redpine Signals
• Rockwell
• Maxim Integrated
• Microchip Technology
• National Semiconductor
• NEC
• NXP Semiconductors
• Nuvoton Technology
• Panasonic
• Silicon Laboratories
• Silicon Motion
• Sony
• Texas Instruments
• Toshiba
• Spansion
• STMicroelectronics
• Ubicom
• Xilinx
• XMOS
• ZiLOG 

Applications of Microcontroller 

Nowadays you can find microcontrollers in all types of electronic devices. Any automobile or other device which measures, controls, calculates, stores, or displays information must have a microcontroller chip inside it.

The microcontrollers used widely are in the industries (microcontrollers widely used for controlling engines and power controls in automobiles). Various other equipment contains microcontrollers inside it, such as keyboards, printers, computer mice, modems, and other peripherals. In various equipment, microcontrollers make it easy to add some features like the power to store measurements, to form and store user routines, and to display messages and waveforms.

Various other products that use microcontrollers include digital camcorders, optical players, LCD/LED display units, etc. And these are just a couple of examples.

Here are some applications of a microcontroller are follows:

• Consumer Electronics Products – Any automatic home appliance like Robots, Toys, Cameras, Washing machines, Microwave Ovens, etc.
• Instrumentation and Process Control – Multimeter, Leakage Current Tester, Oscilloscopes, Data Acquisition and Control, etc.
• Fire Detection – Security alarm, Safety devices, etc.
• Medical Instruments – Medical machines like ECG, Accu-Chek, etc.
• Communication technology – Telephone Sets, Cell Phones, Answering Machines, etc.
• Multimedia Application – Mp3 Player, PDAs, etc.
• Office Machines – Fax machine, Printers, etc.
• Automobile – Auto-braking system, Speedometer, etc. 

Microcontrollers vs. Microprocessors 

The difference between the Microcontrollers and Microprocessors are given below: