The Scalable Serdes Framer Interface (SFI-S) is an Optical Internetworking Forum (OIF) standard that defines the electrical connections between devices on a typical optical communications line card. An n-bit wide SFI-S configuration contains n data channels and one control channel for interface skew compensation. This application note describes a ten data channel SFI-S design targeting Xilinx 7 series FPGAs using GTX or GTH serial transceivers to implement an aggregate 111.8 Gb/s bidirectional interface. The hardware-verified Verilog HDL reference design provides significant skew compensation and fine-grained control of skew tracking. A synthesizable example design with PRBS31 generator and checker logic enables simple simulation and hardware demonstration of the reference design.
