Reconfigurable Field Programmable Gate Arrays: Basic Concepts

The first FPGA models have been introduced during the 1980s. The first programmable logic, almost similar to the FPGA, is comparable to the first costly programmable devices called programmable logic devices (PLDs) but able to implement a significantly higher amount of logic. Two first categories of devices have been developed: antifuse, consisting of an electrically programmable configuration memory which can be programmed only a single time and FPGA based on a configuration memory with SRAM cells that can be configured. Despite the antifuse devices were initially preferred for the more stability of the configuration memory, at the end of the 1980s, most of the preliminary dependability problems were solved, and the technology based on SRAM has started growing thanks to the volatility of the configuration memory that enables a wide range of applications. The FPGA architecture based on SRAM configuration memory can be configured in a very reduced time with whatever processor, differently from the antifuse FPGA that could be programmed only a single time.