Digital Logic Design, 4th Edition

11

Programmable logic devices

11.1 Introduction

Traditional methods of logic design employing SSI and MSI circuits have been strongly challenged in recent years as a result of advances in technology which have led to the development of LSI programmable logic devices (or PLDs). The programmable logic devices currently available to the logic designer may broadly be classified as Read Only Memories (ROMs), a variety of different types of programmable logic arrays (PLAs), and several different brands of field programmable gate arrays (FPGAs) which may roughly be considered as developments of the PLA concept.

The basis of these devices is two-dimensional arrays of identical cells, usually laid out on the silicon chip in regular rows and columns. ...