The eXtended Attachment Unit Interface (XAUI) core is a high-performance, low-pin count 10-Gb/s interface intended to allow physical separation between the data link layer and physical layer devices in a 10-Gigabit Ethernet system. The XAUI core implements a single-speed full-duplex 10-Gb/s Ethernet eXtended Attachment Unit Interface (XAUI) solution for the Virtex-7, Kintex-7, Virtex-6, Virtex-5, Virtex-4, and Spartan-6 Field Programmable Gate Array (FPGA) devices.