COM20020I_06 Datasheet, PDF (5/65 Pages) SMSC Corporation – 5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM

5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
2.0 General Description
SMSC's COM20020I 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
COM20020I 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 5 Mbps when using the COM20020I.
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
5 Mbps maximum data rate, and the internal diagnostics make the COM20020I the highest performance embedded
communications device available. With only one COM20020I 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 COM20020I ULANC.
SMSC COM20020I 3.3V
Page 5
DATASHEET
Revision 12-06-06