ABSTRACT
Digital systems can be implemented using several hardware technologies. As shown in Fig. 12.1, field programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), and application specific integrated circuits (ASICs), are integrated circuits whose internal functional operation is defined by the user. ASICs require a final customized manufacturing step for the user-defined function. Programmable logic devices such as CPLDs or FPGAs require user configuration or programming to implement the desired function. Full custom VLSI devices are internally hardwired and optimized to perform a fixed function. Examples of full custom very large scale integrated (VLSI) devices include the microprocessor and RAM chips used in computers.
