Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM
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
engine is the ideal solution for embedded control applications because it provides a deterministic token-
passing protocol, a highly reliable and proven networking scheme, and a data rate of up to 312.5 Kbps
when using the COM20019I.
A token-passing protocol provides predictable response times because each network event occurs within a
predetermined time interval, based upon the number of nodes on the network. The deterministic nature of
ARCNET is essential in real time applications. The integration of the 2Kx8 RAM buffer on-chip, the
Command Chaining feature, the maximum data rate, and the internal diagnostics make the COM20019I
the highest performance embedded communications device available. With only one COM20019I and one
microcontroller, a complete communications node may be implemented.
For more details on the ARCNET protocol engine and traditional dipulse signaling schemes,
please refer to the ARCNET Local Area Network Standard, available from Standard Microsystems
Corporation or the ARCNET Designer's Handbook, available from Datapoint Corporation.
For more detailed information on cabling options including RS485, transformer-coupled RS-485
and Fiber Optic interfaces, please refer to the following technical note which is available from
Standard Microsystems Corporation: Technical Note 7-5 - Cabling Guidelines for the COM20020
ULANC.
SMSC COM20019I
Page 5
Rev. 03-07-06
DATASHEET
SMSC [ SMSC CORPORATION ]
