Mohammed Fathy

Central Processing Unit: 
The CPU consists of ALU (Arithmetic and Logic Unit), register unit and control 
unit. The CPU fetches the stored instructions from the program memory, data 
word from data memory or from an input device and after processing the data 
stores the result in data memory or sends it to an output device. 
a) ALU (Arithmetic and Logic Unit) 
This unit performs computing functions these functions are arithmetic operations 
such as addition, subtraction and logical operation such as AND, OR, XOR, 

Lecture-1 
An Overview of Microprocessor: 
Microprocessor is a controlling unit of a microcomputer, fabricated on a small chip 
that contains millions of transistors connected by wires capable of performing 
Arithmetic Logical Unit (ALU) operations and communicating with the other 
devices connected to it, a multipurpose, clock driven, register based, digital 
integrated circuit which accepted binary data as input, processes it according to 
instructions stored in its memory, and provides results as output as shown in fig 1.