Basic Concepts Of Microprocessor

Microprocessor

A microprocessor is basically the brain of the computer. We can also call it simply a processor or CPU. Furthermore, a microprocessor is basically a computer processor that is mounted on a single IC (Integrated Circuit). It means that all the functions of the processor are included on a single chip. In 1971, Intel introduced the first commercial microprocessor which was Intel 4004.

Furthermore, the basic task of a microprocessor is to input the instructions from the memory, decode, and process them and produce the output. It performs three basic tasks while processing the information. They are as follows:

1. Performing some basic calculations using ALU for example, addition, division, multiplication, subtraction, etc.
2. Moving data from one location to another.
3. It has a Program Counter (PC), which is a pointer that stores the address of the next instruction. It keeps track of the PC and performs instructions accordingly.

Types of Microprocessors

We have three basic types of microprocessors. They are as follows:

1. CISC (Complex Instruction Set Computer)

As the name suggests, the instructions are in a complex form. It means that a single instruction can contain many low-level instructions. For example loading data from memory, storing data to the memory, performing basic operations, etc. Besides, we can say that a single instruction has multiple addressing modes. Furthermore, as there are many operations in single instruction they use very few registers.

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

2. RISC (Reduced Instruction Set Computer)

As per the name, in this, the instructions are quite simple, and hence, they execute quickly. Moreover, the instructions get complete in one clock cycle and also use a few addressing modes only. Besides, it makes use of multiple registers so that interaction with memory is less.

Examples are IBM RS6000, DEC Alpha 21064, DEC Alpha 21164, etc.

3. EPIC (Explicitly Parallel Instruction Computing)

It allows the instructions to compute parallelly by making use of compilers. Moreover, the complex instructions also process in fewer clock frequencies. Furthermore, it encodes the instructions in 128-bit bundles. Where each bundle contains three instructions encoded in 41 bits each and a 5-bit template. This 5-bit template contains information about the type of instructions and that which instructions can be executed in parallel.

Examples are IA-64 (Intel Architecture-64), etc.

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• Clock Speed
• Types of Microprocessor

Characteristics of a Microprocessor

There are three important characteristics of a microprocessor. They are as follows:

• Clock Speed
• Word Size
• Instruction Set

Clock Speed

The speed at which a microprocessor can execute the instructions is called the clock speed. Basically clock speed is the number of cycles that the processor executes per second. We measure it in MHz(MegaHertz) or GHz (Giga Hertz). Here, MHz means 1 million cycles per second and GHz means 1 billion cycles per second. Moreover, a cycle basically means a single electric cycle.  Besides, every microprocessor has an internal clock that regulates the speed at which it executes the instructions.

Word Size

It is the number of bits that a processor can process in a single instruction. Furthermore, the word size decides the amount of RAM that the processor can access at a time. Moreover, it also decides the number of input and output pins on the microprocessor. These pins in to decide the architecture of the processor.

The number of input and output pins is always equal. For example, the first commercial processor Intel 4004 was a 4-bit processor. hence, it has 4 input/output pins. Today, mostly 32-bit or 64-bit are used.

Instruction Set

An instruction is basically a command which tells the computer to operate on some piece of data. The set of machine-level instructions that a microprocessor executes is the instruction set. The operations involved in the instructions can be as follows:

• Arithmetic operations
• Logical operations
• Data transfer
• Input/output operations
• control flow

Parts of a Microprocessor

The basic parts of a microprocessor are as follows:

• CPU
• Bus
• Memory

CPU (Central Processing Unit)

This is a really important part of a computer as it performs all the processing parts of the computer. It processes the data and instructions which the user gives. Moreover, it carries out the calculations and other such tasks. Other names of CPU are Central Processor or Main Processor.  It has the following parts:

1. Arithmetic and Logical Unit

As the name suggests, this unit is responsible for performing arithmetic tasks like addition, subtraction, multiplication, division moreover, it also makes logical decisions like greater than less than, etc. And hence the name, the ‘brain’ of the computer.

2. Control Unit

This unit is responsible for looking after all the processing. It organizes and manages the execution of tasks of the CPU.

3. Registers

These are memory areas which the CPU directly uses for processing. So, it’s function is to store data from input or store data between calculations. Besides, it also stores the output results. Moreover, accessing registers is much faster than accessing the RAM.

4. Decoder

It decodes the instructions from high-level language to machine language and passes them to the CPU.

5. Instruction Register (IR)

It stores the instruction which will execute currently.

Bus

The functional components usually use a bus architecture for communication. A bus is a collection of wires used for the communication of different parts of a computer. Further, it uses electric signals to pass the data and information.

Different Types of Buses used are:

1. Address Bus

The address bus is used to communicate the address of the given data and instructions.

2.Data Bus

The data bus is used to communicate the data from one part to another.

3. Control Bus

The control bus is used to control the signals between different devices. Therefore, in conclusion, we can say that these functional components communicate through this bus architecture. The input device takes the input, then the data is processed and the output devices display the results. Besides, the system bus performs all the communication that the cycle involves.

Memory

The parts of memory are:

Primary Memory

This is the internal memory that stores the data and instructions of the CPU. It is volatile in nature (data is lost when the power is disconnected).

The primary memory has two types:

1. RAM (Random Access Memory)

As per the name, data can be accessed randomly and quickly.

1. ROM (Read Only Memory)

As per the name, we can only read data and cannot write (store) to it.

Secondary Memory

As we know that the primary memory is volatile therefore, we need some devices to store the data permanently so we use some external storage devices for this purpose which we name as the secondary memory. Some examples: CD, DVD, etc.

Frequently Asked Questions (FAQs)

Q1. What is a microprocessor?

A1. A microprocessor is basically a computer processor that is mounted on a single IC (Integrated Circuit). It means that all the functions of the processor are included on a single chip.

Q2. What are the types of microprocessors?

A2. It has basically three types, they are as follows:

• CISC (Complex Instruction Set Computer)
• RISC (Reduced Instruction Set Computer)
• EPIC (Explicitly Parallel Instruction Computing)

Q3. What are the basic parts of a microprocessor?

A3. The basic parts are as follows:

• CPU
• Bus
• Memory