INTRODUCTION TO MICROPROCESSOR
Microprocessor:
The microprocessor can be viewed as a programmable logic device that can be used to control processes or to turn on/off devices.
Microprocessor is a digital device on a chip which can fetch instructions from a memory, decode and execute them i.e. performs certain arithmetic and logical operations, accept data from input device, and send results to output devices. Therefore, a microprocessor interfaced with memory and Input/ Output devices forms a Microcomputer.Basically, there are five building blocks of a digital computer namely:
Input Unit:Through this unit data and instructions are fed to the memory of the computer. The basic purpose of this unit is to read the data into the machine. The program from the memory is read into the machine along with the input data which are required to solve or compute the problem by the machine. The typical devices which are used for this purpose are keyboards, paper tape reader and toggle switches etc.
Memory Unit:The memory unit of a digital computer consists of devices which are capable of storing information. The memory of a computer is used for storing two distinct type of information such as data to be processed by the computer and program through which the result of the desired problem is obtained. Computer program and data are stored in the Memory Unit. This usually consists of chips of both ROMs (Read Only Memories) and RAMs (Random Access Memories) either bipolar or MOS.
Arithmetic and Logical Unit (ALU):This unit is used for performing arithmetic operations such as Addition, Subtraction, Multiplications, division and other logical operations on the data.The control unit guides ALU which of the operations are to be performed. The sequence of the instructions is controlled by the control unit.
Control Unit:The control unit performs the most important function in a computer. It controls all other units and also controls the flow of data from one unit to another for performing computations. It also sequences the operations. It instructs all the units to perform the task in a particular sequence with the help of clock pulses.
Output Unit:After processing of the data in the Arithmetic and Logical Unit, the results are displayed to the output world through this unit. The CRTs (Cathode Ray Tubes), LEDs (Light Emitting Diodes) and Printer etc. form the output unit.
In a computer system ALU and Control Unit are combined in one unit called Central Processing Unit (CPU). The block diagram of a computer is shown in figure
