Page 133 - DCAP108_DIGITAL_CIRCUITS_AND_LOGIC_DESIGNS

Digital Circuits and Logic Design Avinash Bhagat, Lovely Professional University

Notes Unit 8: Memory

CONTENTS
Objectives
Introduction
8.1 Random Access Memory (RAM)
8.2 Read Only Memory (ROM)
8.3 Programmable Read Only Memory (PROM)
8.4 Erasable Programmable Read Only Memory (EPROM)
8.4.1 Cache Memory
8.5 Electrically Erasable Programming Read Only Memory (EEPROM)
8.5.1 EEPROM Structure
8.5.2 EEPROM Limitations
8.6 Programmable Logic Array (PLA)
8.6.1 Minterms
8.6.2 Programming
8.7 Programmable Array Logic (PAL)
8.8 Use of PAL and PLA in Combinational Circuit
8.8.1 Combinational Circuit Implementation with PLA
8.8.2 Programmable Array Logic (PAL)
8.9 Summary
8.10 Keyword
8.11 Review Questions
8.12 Further Readings

Objectives

After studying this unit, you will be able to:
• Explain the random access memory
• Explain the read only memory
• Describe the programmable read only memory
• Describe the erasable programable read only memory
• Discuss the electrically erasable programable read-only memory
• Explain the programable logic array
• Describe the programmable array logic
• Discuss the use of PAL and PLA in combinational circuit

Introduction

The CPU contains necessary circuitry for data processing controlling other components of the
computer. However, one thing it does not have built into it is the place to store programs and data
needed during data processing. CPU contains several registers for storing data and instructions
but they can store only a few bytes at a time. They are just sufficient to hold only one or two

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