TABLE OF CONTENTS This chapter provides a brief overview of programmable logic technology and history. It is intended for designers with limited programmable logic experience. Since the primary focus of this book is on rapid design implementation with FPGA technology, the technology overview is at a higher level. This chapter provides a high-level overview of programmable logic technology. For a more detailed overview of programmable logic, refer to The Design Warrior's Guide to FPGAs by Clive Maxfield.
Programmable logic devices have the potential to implement a broad range of functionality, unlike the fixed-function devices that preceded them. It is the flexibility inherent in FPGA technology that allows design teams to rapidly develop and field complex system implementations.
In this chapter, we will first review programmable logic devices in general, and then go on to a detailed look at FPGA devices, with an eye toward their suitability for rapid prototyping and design.
Programmable logic devices (PLDs) are divided into three primary architectural groups:
Simple Programmable Logic Devices (SPLDs)
Complex Programmable Logic Devices (CPLDs)
Field Programmable Gate Arrays (FPGAs)
While each of these programmable logic device architectures have typical focused applications, they also have some common feature overlap which leads to some overlap of applications. Figure 2.1 illustrates the overlap between the three PLD technologies. For example, some applications such as address decoding could be implemented in either a CPLD or an FPGA. Implementation within an FPGA allows this function to be integrated with a larger range...
