Chapter 1 GENERAL DESCRIPTION
SMSC's COM20019I is a member of the family of Embedded ARCNET Controllers from Standard Microsystems Corporation. The device is a general purpose communications controller for networking microcontrollers and intelligent peripherals in industrial, automotive, and embedded control environments using an ARCNET protocol engine. The flexible microcontroller and media interfaces, eight- page message support, and extended temperature range of the COM20019I make it the only true network controller optimized for use in industrial, embedded, and automotive applications. Using an ARCNET protocol

Product Features
■ New Features:
   − Data Rates up to 312.5 Kbps
   − Programmable Reconfiguration Times
■ 28 Pin PLCC and 48 Pin TQFP Packages
■ Ideal for Industrial/Factory/Building Automation and Transportation Applications
■ Deterministic, (ANSI 878.1), Token Passing ARCNET Protocol
■ Minimal Microcontroller and Media Interface Logic Required
■ Flexible Interface For Use With All Microcontrollers or Microprocessors
■ Automatically Detects Type of Microcontroller Interface
■ 2Kx8 On-Chip Dual Port RAM
■ Command Chaining for Packet Queuing
■ Sequential Access to Internal RAM
■ Software Programmable Node ID
■ Eight, 256 Byte Pages Allow Four Pages TX and RX Plus Scratch-Pad Memory
■ Next ID Readable
■ Internal Clock Scaler for Adjusting Network Speed
■ Operating Temperature Range of -40oC to +85oC
■ Self-Reconfiguration Protocol
■ Supports up to 255 Nodes
■ Supports Various Network Topologies (Star, Tree, Bus...)
■ CMOS, Single +5V Supply
■ Duplicate Node ID Detection
■ Powerful Diagnostics
■ Receive All Packets Mode
■ Flexible Media Interface:
   − RS485 Differential Driver Interface For Low Cost, Low Power, High Reliability