Microprocessor Tutorial

Microprocessor Tutorial

A microprocessor is a controlling unit of a micro-computer, fabricated on a small chip capable of performing Arithmetic Logical Unit (ALU) operations and communicating with the other devices connected to it. In this tutorial, we will discuss the architecture, pin diagram and other key concepts of microprocessors.


This tutorial is designed for all those readers pursing either Bachelor’s or Master’s degree in Computer Science. It will help them understand the basic concepts related to Microprocessors.


In this tutorial, all the topics have been explained from elementary level. Therefore, a beginner can understand this tutorial very easily. However if you have a prior knowledge of computer architecture in general, then it will be quite easy to grasp the concepts explained here.

Frequently Asked Questions about Microprocessor

There are some very Frequently Asked Questions(FAQ) about Microprocessor, this section tries to answer them briefly.

A microprocessor is like the brain of a computer. It is a small electronic chip that performs the basic calculations and controls the flow of information within the computer. Think of it as the engine that drives the computer's operations. The microprocessor receives instructions from software programs, processes them, and then executes tasks such as running applications, performing calculations, and managing input and output devices like keyboards and monitors. It is the central component that enables a computer to function and carry out tasks.

Microprocessor was invented by a team of engineers led by Ted Hoff, Federico Faggin, and Stan Mazor at Intel Corporation in the early 1970s. They developed the first commercially available microprocessor, the Intel 4004, which was introduced in 1971.

The features of a microprocessor include −

  • Processing Power − Microprocessors are capable of performing millions or even billions of calculations per second, enabling them to execute complex tasks quickly.

  • Versatility − Microprocessors can execute a wide range of instructions and tasks, making them suitable for various applications, from simple household appliances to advanced computers.

  • Integration − Microprocessors integrate multiple components, such as arithmetic logic units (ALUs), control units, and memory, onto a single chip, reducing size and complexity while increasing efficiency.

  • Scalability − Microprocessors come in different configurations and speeds, allowing them to be modified to the specific needs of different devices and applications.

  • Power Efficiency − Modern microprocessors are designed to operate efficiently while consuming minimal power, making them suitable for battery-powered devices like smartphones and laptops.

  • Interconnectivity − Microprocessors can communicate with other components and devices through input/output ports, enabling them to interact with external sensors, displays, and storage devices.

The world's first microprocessor is the Intel 4004. It was invented by a team of engineers at Intel Corporation, led by Federico Faggin, Ted Hoff, and Stanley Mazor, and introduced in 1971. The Intel 4004 was a groundbreaking invention because it combined the functions of multiple transistors onto a single chip, making it the first complete central processing unit (CPU) on a microchip. This innovation paved the way for the development of modern computers and electronic devices, as it allowed for smaller, faster, and more efficient computing capabilities.

A microprocessor works like the brain of a computer. It receives instructions from software programs, processes them, and executes tasks to perform various functions. Following is the basic overview of how it works −

  • Fetch − The microprocessor fetches instructions from the computer's memory, which are stored as binary code (0s and 1s).

  • Decode − It decodes these instructions to understand what action needs to be performed.

  • Execute − The microprocessor carries out the instructions by performing calculations, moving data around, or interacting with other components.

  • Writeback − After executing the instruction, the microprocessor may write the result back to memory or output it to an external device.

This process repeats continuously, allowing the microprocessor to handle complex tasks and run software programs, ultimately enabling the computer to perform various functions and operations.

Registers are used inside microprocessors to store and manage data temporarily while the microprocessor performs calculations and executes instructions. Think of registers as small storage spaces within the microprocessor where data can be quickly accessed and manipulated. They are much faster to access than the computer's main memory, allowing the microprocessor to work more efficiently.

Registers are used to hold operands for arithmetic and logical operations, store memory addresses for accessing data, and keep track of the current state of the microprocessor during program execution.

A flag in a microprocessor is a small piece of information or a signal that indicates a specific condition or state of the microprocessor during the execution of a program. Flags are used to keep track of various conditions or events that occur during the processing of instructions.

For example, flags may indicate whether a certain arithmetic operation resulted in a carry or overflow, whether a comparison between two values was true or false, or whether a certain condition has been met. These flags are stored in special registers within the microprocessor and are used by the microprocessor to make decisions and control the flow of the program.

There are primarily two types of microprocessors −

  • General-Purpose Microprocessors − These are versatile microprocessors designed to handle a wide range of tasks and applications. They are commonly found in personal computers, laptops, and servers. General-purpose microprocessors are capable of executing various types of software programs, from word processing and web browsing to gaming and multimedia applications. Examples include Intel's Core series, AMD's Ryzen series, and ARM-based processors used in smartphones and tablets.

  • Special-Purpose Microprocessors − These are microprocessors designed for specific applications or tasks. They are optimized for particular functions or industries and may have features tailored to meet the requirements of those applications. Examples include microcontrollers used in embedded systems, digital signal processors (DSPs) used in audio processing and telecommunications, and graphics processing units (GPUs) used in rendering images and videos.

The basic parts of a microprocessor include −

  • Arithmetic Logic Unit (ALU) − This is the part of the microprocessor that performs arithmetic operations (like addition and subtraction) and logical operations (like AND, OR, and NOT) on data.

  • Control Unit − This part of the microprocessor coordinates the operations of the other parts of the microprocessor. It fetches instructions from memory, decodes them, and controls the flow of data between the different parts of the microprocessor.

  • Registers − These are small storage locations inside the microprocessor that temporarily hold data, instructions, or addresses. Registers are used for storing intermediate results, operands for arithmetic operations, memory addresses, and other temporary data during processing.

  • Clock − This is a timing device that synchronizes the operations of the microprocessor. It generates electrical pulses at regular intervals, called clock cycles, which control the speed at which instructions are executed and data is processed.

  • Cache Memory − Cache memory is a small, high-speed memory located inside the microprocessor that stores frequently accessed data and instructions. It helps speed up data access and execution by providing fast access to commonly used data and instructions.

In simple terms, the fastest microprocessor is the one that can perform calculations and execute instructions at the highest speed. Some of the fastest microprocessors are found in high-performance computing systems, supercomputers, and server processors designed for demanding tasks like scientific simulations, data analysis, and artificial intelligence. These microprocessors often have multiple cores, high clock speeds, and advanced architectures optimized for parallel processing.

Examples include Intel's Xeon Scalable processors, AMD's EPYC processors, and specialized processors like NVIDIA's GPUs used for parallel computing tasks. The speed of a microprocessor is measured in terms of clock speed (measured in GHz) and the number of instructions it can execute per second, known as instructions per second (IPS).