An FPGA is a piece of hardware that is very similar to an ASIC with one exception. An ASIC is a chip that has been configured to perform one type of computation hard (for example, mining the Equihash algorithm). FPGA is a chip that can be reprogrammed to perform any operation. In the field of cryptocurrency mining, you can reconfigure your FPGA from CryptoNight to Lyra2z mining within a second.CRYPTO-MINING.BLOG — Your tutorial on Bitcoin and Altcoin mining