FPGA, Chinese means field programmable gate array, developed on the basis of several other programmable devices, such as PAL, GAL, CPLD, as a semi-custom circuit in the field of ASIC (application specific integrated circuit), it not only solves the shortcomings of the custom circuit, but also overcomes the shortcomings of the original programmable gate device circuit Although it has better reasons than ASIC, it can't replace ASIC.