Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.A field-programmable gate array is an integrated circuit designed to be configured by the customer or designer after manufacturing hence field-programmable. The FPGA configuration is generally specified using a hardware description language similar to that used for an application-specific integrated circuit FPGAs can be used to implement any logical function that an ASIC could perform. The ability to update the functionality after shipping, and the low non-recurring engineering costs relative to an ASIC design offer advantages for many applications. FPGAs contain programmable logic components called logic blocks, and a hierarchy of reconfigurable interconnects that allow the blocks to be wired together somewhat like a one-chip programmable breadboard. Logic blocks can be configured to perform complex combinational functions, or merely simple logic gates like AND and XOR. In most FPGAs, the logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory.