Microprocessor Tutorial

Microprocessor Tutorial

A microprocessor is an electronic device used in computing devices like computers, smartphones, smart watches, and many other for data processing, performing logical and control operations. Microprocessors are generally built in the form an integrated circuit (IC).

A typical microprocessor consists of two main units namely, arithmetic logic unit and control circuitry. A microprocessor is also termed as CPU (Central Processing Unit) in personal computers. The microprocessor is a digital integrated circuit that works by taking binary data as input and processing this data as per the instructions provided. Finally, it produces a result in the binary form.

Microprocessors use both combinational and sequential circuits to perform arithmetic and logical operations in a digital system.

What is a Microprocessor?

A microprocessor is nothing but a semiconductor electronic device designed to perform data processing and digital operations in a computing machine like a computer. It is also termed as a processor or central processing unit or CPU. It is generally built in the form of a single IC (integrated circuit). The first commercially available microprocessor was developed by Intel Corporation in the year of 1971, which was named as Intel 4004.

The primary function of a microprocessor is to take digital data from user, process them according to instructions, and produce the output. Hence, it performs three basic functions namely,

• Inputting
• Processing
• Outputting

Here, it is also important to know that a microprocessor is different from a microcontroller which combines a complete computing system on a single chip.

Block Diagram of Microprocessor

The block diagram of a typical microprocessor is shown in the following figure −

It consists of three main parts which are described as follows −

• Arithmetic Logic Unit (ALU) − It is an electronic circuit that performs arithmetic and logical operations on data received from an input device or memory.
• Control Unit (CU) − This electronic circuit of the microprocessor is responsible controlling the flow of data and instructions within the device or the system.
• Register Array − Register array is nothing but a collection of digital registers to provide small and fast storage to temporarily hold data and instructions in the microprocessor during processes.

In addition to these three basic components, modern microprocessors also consist of cache memory as well.

How does a Microprocessor Work?

The working of a microprocessor can be understood by breaking it down into the following four key steps −

• Fetch − It is the very first function that a microprocessor performs. In this step, the microprocessor access data and instructions from memory unit or an input device.
• Decode − After receiving data and instructions, the microprocessor decodes them and interprets for computing process.
• Execute − In this step, the microprocessor performs the requested operations on the data.
• Store − Finally, the results produced by the operations are stored in the memory unit.

Hence, a typical microprocessor completes its working in four steps, where each step represents a specific task or function.

Types of Microprocessors

Based on the architecture, microprocessors are broadly classified into the following three types −

CISC (Complex Instruction Set Computer) Microprocessor

In CISC microprocessors, a single instruction contains multiple low-level instructions. For example, a single instruction in a CISC microprocessor can be like retrieving data from memory unit and storing data into memory. This one instruction contains two low-level instructions. This type of microprocessor uses very few registers, as a single instruction can perform many operations.

Examples of CISC microprocessors include Intel 386, 486, Pentium, Pentium II, Pentium Pro, etc.

RISC (Reduced Instruction Set Computer) Microprocessor

RISC microprocessors has a quite simple architecture and thus they are capable in faster execution of operations. In RISC microprocessors, small and optimized instructions are used to perform tasks at a faster rate. In these microprocessors, an instructions execution completes in one clock cycle.

Because RISC microprocessors use multiple registers, thus they have fewer interactions with the main memory. Some common examples of RISC microprocessors are Alpha 21164, IBM RS6000, Alpha 21064, etc.

EPIC (Explicitly Parallel Instruction Computing) Microprocessor

A type of microprocessor that can execute instructions in parallel by using complier is termed as an EPIC microprocessor. Hence, EPIC microprocessors make use of complier rather than an on-die circuitry to control the parallel execution of instructions.

EPIC microprocessors allow processing of complex instructions in fewer clock frequencies. They also encode instructions in 128-bit bundles, each bundle has 3 instructions of 41-bit each and a 5-bit template. This 5-bit template contains information about the instructions that can be executed in parallel. Intel Architecture-64 is a common example of EPIC microprocessor

Applications of Microprocessors

Today, microprocessors are being used in almost all electronic devices and systems used in household to industries. Some common applications of microprocessors depending on their nature are listed below −

• Microprocessors are used in a wide range of common electronic and computing devices like laptops, desktops, smart watches, smart TVs, etc.
• Microprocessors are also used in microcontrollers to perform data processing and control operations.
• Microprocessors specially designed for digital signal processing are used in applications like telecommunication, audio processing, image processing, etc.
• Microprocessors are also used in robotic or autonomous devices like surveillance drones, autonomous aircrafts, etc.
• The specialized microprocessors named Application Specific Integrated Circuits (ASICs) microprocessors are designed for specific tasks and customization depending on the application requirements.
• GPU (Graphical Processing Unit) microprocessors are designed and used for performing high performance graphics functions.
• Microprocessors are also used in network devices like switches, routers, or security devices to process network data packets. These microprocessors are highly optimized for this function.
• Some microprocessors, known as coprocessors, are used to provide auxiliary processing support to the main processor of a system.

Important Terms Related to Microprocessors

In this section, we have picked up and defined some most important terms related to microprocessors. These terms will be very helpful for readers to understand the concepts covered in the tutorial.

Central Processing Unit (CPU)

CPU is considered the brain of a computing machine. It is the most important part of the system that performs operations, calculations, logic functions, execution of instructions, and manages data flow across the system.

Instruction Set Architecture (ISA)

ISA is a design architecture of microprocessors. It defines the set of instructions that the microprocessor can execute. There are two different types of ISAs commonly used in microprocessors namely, RISC (Reduced Instruction Set Computing) and CISC (Complex Instruction Set Computing).

Arithmetic Logic Unit (ALU)

ALU is one of the key components of a microprocessor that is basically an electronic circuit designed to perform arithmetic and logic operations.

Control Unit (CU)

It is another key part of a microprocessor which is responsible for controlling the execution of instructions and managing the data flow among components of the system.

Clock Speed

Clock speed is a performance measurement parameter of a microprocessor that indicates how fast the processor can execute instructions. It is generally measured in MHz or GHz.

Core

In the case of a microprocessor, the term core is used to represented an independent processing unit. Hence, microprocessors are available 1 core, dual core, quad core, octa core, etc. designs.

Cache Memory

Cache memory is a SRAM (Static Random Access Memory) used as an integral part of a microprocessor. It is a small and high-speed memory that provides a storage space for most frequently accessed data and instructions.

Bus

In microprocessors, Bus represents a communication channel for data and instructions. There are two types of buses are very common in microprocessors namely, data bus that allows transmission of data between CPU and other hardware components and address bus that allows access of memory address to the microprocessor.

Floating Point Unit (FPU)

FPU, also known as Math Coprocessor, is a specially designed component to handle complex arithmetic operations that involve the use of decimal points.

Pipelining

Pipelining is a technique that breaks down big tasks into smaller subtasks and accomplishes them in stages. This technique is used to enhance the efficiency of the microprocessor.

Multithreading

Multithreading is a processing technique in which a single core microprocessor executes multiple threads of a process concurrently. The primary objective of multithreading is to enhance performance and optimize the resource utilization.

Overclocking

As the name implies, overclocking is a process that makes the speed of the microprocessor greater than its factory setting to enhance its performance. However, it can lead to generation of more heat.

Die

Die is nothing but a piece of silicon within an integrated circuit that houses the entire microprocessor circuit.

ASIC (Application Specific Integrated Circuit)

ASIC is a specialized and customizable microprocessor that can be optimized to meet the requirements of a specific application.

Digital Signal Processor

Digital signal processor is a microprocessor specially designed for applications like audio, video, and image processing.

Register

A register is a small, high-speed memory device used as a part of a microprocessor unit. It is provided in microprocessors to hold data and instructions during processing temporarily.

Integrated Circuit (IC)

IC is also called as Chip. It is an electronic device that combines several components like transistors, capacitors, diodes, resistors, etc. into a small silicon wafer.

What You Will Learn in This Microprocessor Tutorial?

This tutorial is designed to cover most important concepts, from basics to advance, in microprocessor. Here is the detailed TOC of the tutorial that list out chapters covered and describes what each chapter covers −

Who This Microprocessors Tutorial is for?

This microprocessors tutorial is designed for all those students and readers pursing either Bachelors or Masters degree courses in computer science, electrical and electronics, information technology, or related engineering or technology branches. This tutorial will help the students understanding the basic to advanced concepts related to microprocessors and microcontrollers.

Prerequisites to Learn Microprocessors

This tutorial explains all the topics in a lucid manner and simple language; hence it is suitable for both beginners and professionals. However, a prior knowledge of computer architecture can make it quite easy to grasp the concepts covered here.

FAQs on Microprocessor

In this section, we have collected a set of Frequently Asked Questions (FAQs) on Microprocessor followed by their answers −

What is microprocessor?

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.

Who invented the microprocessor?

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.

What are the features of microprocessor?

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.

Which is the world's first microprocessor?

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.

How Does a Microprocessor Work?

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.

Why Registers Are Used Inside of Microprocessors?

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.

What is flag in microprocessor?

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.

What are the different types of microprocessor?

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.

What are the basic parts of a microprocessor?

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.

What is the fastest microprocessor?

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).