Adaptation of FDDI physical layer chip to Playthrough protocol

Data flow design and very-high-speed integrated circuit (VHSIC) hardware description language (VHDL) behavioral simulation are presented for a physical layer encoder/decoder (ENDEC) chip that supports use of a Playthrough protocol on ring topology local area networks. The authors describe the Playthrough protocol´s operational concept. The ENDEC design uses as much of the fiber distributed data interface (FDDI) standard as possible to support a 100-Mb/s data transfer rate on fiber-optic media with a chip that is plug compatible with the Advanced Micro Devices (AMD) FDDI ENDEC chip. The design uses an adaptation of the AMD FDDI ENDEC data flow structure; however, because the Playthrough media access control (MAC) protocol differs from FDDI´s, a new control flow structure and a different internal structure are required to accommodate Playthrough MAC (PMAC) chip functions.<>