Introduction

The term microcomputer is used to describe a system that includes at minimum a microprocessor, program memory, data memory, and an input-output (I/O) device. 

Some microcomputer systems include additional components such as timers, counters, and analog-to-digital converters. Thus, a microcomputer
system can be anything from a large computer having hard disks, floppy disks, and printers to a single-chip embedded controller.
Here we are going to consider only the type of microcomputers that consist of a single silicon chip. Such microcomputer systems are also called microcontrollers, and they are used in many household goods such
as microwave ovens, TV remote control units, cookers, hi-fi equipment, CD players, personal computers, and refrigerators. Many different microcontrollers are available on the market. Here we shall be
looking at programming and system design for the PIC (programmable interface controller) series of microcontrollers manufactured by Microchip Technology Inc.

• PIC is a family of micro-controllers made by Microchip Technology.

• The original PIC1650 was developed by General Instruments.

• PIC stands for “Programmable Intelligent Computer” although it is now associated with

“Programmable Interface Controller.”

• PICs use an instruction set that varies in length from about 35 instructions for the

low-end PICs to more than 70 for the high-end devices.

                                                   Internal Structure Of A Micro controller