The XCFxx series of Flash EPROMs provide an easy-to-use, cost-effective and reprogrammable method for storing large Xilinx FPGA configuration bitstreams.
In-System Programmable Flash memory devices for configuration of Xilinx FPGAs
IEEE Standard 1149.1/1532 Boundary-Scan (JTAG) support for Programming, Prototyping, and Testing
Cascadable for storing longer or multiple bitstreams
I/O pins compatible with voltage levels ranging from +1.5V to +3.3V