Lecture-02: Operation of Microprocessor/ Machine Cycle (MPU)

 Operation of Microprocessor / Machine Cycle

How does a Microprocessor Work?

The microprocessor follows a sequence: Fetch, Decode, and then Execute.

Initially, the instructions are stored in the memory in a sequential order. The microprocessor fetches those instructions from the memory, then decodes it and executes those instructions till STOP instruction is reached. Later, it sends the result in binary to the output port. Between these processes, the register stores the temporarily data and ALU performs the computing functions.

Basic operation of Microprocessor/ Machine cycle:

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:

Ø   Performing some basic calculations using ALU for example, addition, division, multiplication, subtraction, etc.

Ø Moving data from one location to another.

Ø 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.

 

                                                             Figure: Machine Cycle

List of Terms Used in a Microprocessor:

Here is a list of some of the frequently used terms in a microprocessor −

·   Instruction Set − It is the set of instructions that the microprocessor can understand.

·        Bandwidth − It is the number of bits processed in a single instruction.

·      Clock Speed − It determines the number of operations per second the processor can perform. It is expressed in megahertz (MHz) or gigahertz (GHz).It is also known as Clock Rate.

·      Word Length − It depends upon the width of internal data bus, registers, ALU, etc. An 8-bit microprocessor can process 8-bit data at a time. The word length ranges from 4 bits to 64 bits depending upon the type of the microcomputer.

·    Data Types − The microprocessor has multiple data type formats like binary, BCD, ASCII, signed and unsigned numbers.

Features of a Microprocessor:

Here is a list of some of the most prominent features of any microprocessor −

·      Cost-effective − The microprocessor chips are available at low prices and results its low cost.

·      Size − The microprocessor is of small size chip, hence is portable.

· Low Power Consumption − Microprocessors are manufactured by using metaloxide semiconductor technology, which has low power consumption.

·    Versatility − The microprocessors are versatile as we can use the same chip in a number of applications by configuring the software program.

·     Reliability − The failure rate of an IC in microprocessors is very low, hence it is reliable.