GENERAL DESCRIPTION
The SMSC COM90C66 is a special purpose communications controller for interconnecting processors and intelligent peripherals using the ARCNET Local Area Network. The COM90C66 is unique in that it integrates the core ARCNET logic found in Standard Microsystems original COM90C26 and COM90C32 with an on-chip 2K x 8 RAM, as well as the 16-bit data bus interface for the IBM PC/AT.

FEATURES
• ARCNET LAN Controller/Transceiver/Support Logic/Dual-Port RAM
• Integrates SMSC COM90C65 with 16-Bit Data Bus, Dual-Port RAM, and Enhanced Diagnostics Circuitry
• Includes IBMÒ PC/ATÒ Bus Interface Circuitry
• Supports 8- and 16-Bit Data Buses
• Full 2K x 8 On-Chip Dual-Port Buffer RAM
• Zero Wait State Arbitration for Most AT Buses
• SMSC COM90C26 Software Compatible
• Command Chaining Enhances Performance
• Supports Memory Mapped and Sequential I/O Mapped Access to the Internal RAM Buffer
• Compatible with the SMSC HYC9058/68/ 88 (COAX and Twisted Pair Drivers)
• Token Passing Protocol with Self Reconfiguration Detection
• Variable Data Length Packets
• 16 Bits CRC Check/Generation
• Includes Address Decoding Circuitry for OnChip RAM, PROM and I/O
• Supports up to 255 Nodes
• Contains Software Accessible Node ID Register
• Compatible with Various Topologies (Star, Tree, Bus, ...)
• On-Board Crystal Oscillator and Reset Circuitry
• Low Power CMOS, Single +5V Supply