Digital Design with Programmable Logic Devices

This chapter covers various aspects of digital design with programmable devices, e.g., programmable logic arrays (PLAs), complex programmable logic devices (CPLDs), and field-programmable gate arrays (FPGAs). Moreover, this chapter emphasizes on uses of FPGA on various image processing and biomedical applications. Programmable logic devices (PLDs) are electronic circuits that can be programmed to perform certain functions and can be modified at a later instant of time to achieve other functionality. The reconfigurability and reusability makes PLD more attractive from user point of view. For flexible design, users need to have knowledge on digital systems, the designing environment, tools and methodology followed, and use of language to describe the hardware circuitry. Digital designs involve basic logic gates whose combinational effort creates logic functions. Complex algorithms are produced by association of several complex logic functions. These algorithms act as building blocks for different applications. These applications demand multifunctional integrated circuits with reconfiguring and reprogramming capability. To achieve this, several programmable devices such as PLAs, CPLDs, and FPGAs are developed. All of these devices have their own benefits and limitations and are utilized for specific applications. Amount of flexibility achieved with particular PLD depends on its type, which in turn decided by the inherent hardware resources available, operating voltage, and the required speed grade. Nowadays, FPGAs are the best choice for image processing and biomedical applications due to their prototyping capability with parallel architectures, high memory capacity, logic density, and low energy consumption.