Logic describes the basic functions of electronics. Writing logic for programmable logic devices (PLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGA) allows engineers to program devices that are very fast.
PLDs are Programmable Logic Devices (PLDs) and CPLDs are Complex Programmable Logic Devices (CPLDs).
Field Programmable Gate Arrays (FPGAs) are like microcontrollers that can be configured to process inputs in a variety of ways and can be programmed to work very quickly. They are not used as frequently as microcontrollers or microprocessors for simple electronics because they are more expensive and use more power, but when they are needed they can be very useful.