The In System Flash (ISF) is type of serial flash memory and it is present only on the Spartan™ 3AN devices. The Spartan™ 3AN FPGA family is the sub-family of Spartan™ 3A FPGA devices. The XPS InSystem Flash IP Core is 32-bit slave peripheral that connects to PLBv46 (Processor Local Bus with AMD simplifications) and provides access to the ISF using Serial Peripheral Interface (SPI) protocol.