Features: · New Features
- Data Rates up to 5 Mbps
- Programmable Reconfiguration Times
· 24 Pin DIP, 28 Pin PLCC Package
· 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 and Clock Multiplier 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 +3.3V Supply
· Duplicate Node ID Detection
· Powerful Diagnostics
· Receive All Packets Mode
· Flexible Media Interface:
- Traditional Hybrid Interface For Long Distances up to Four Miles at 2.5Mbps.
- RS485 Differential Driver Interface For Low Cost, Low Power, High ReliabilitySpecificationsOperating Temperature Range................................................................................................. -40oC to +85oC
Storage Temperature Range ..................................................................................................-55oC to +150oC
Lead Temperature (soldering, 10 seconds)..........................................................................................+325 oC
Positive Voltage on any pin, with respect to ground .........................................................................VDD+0.3V
Negative Voltage on any pin, with respect to ground ...............................................................................-0.3V
Maximum VDD .............................................................................................................................................+7V
*Stresses above those listed may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other condition above those indicated in the operational sections of this specification is not implied.
Note: When powering this device from laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be exceeded or device failure can result. Some power supplies exhibit voltage spikes or "glitches" on their outputs when the AC power is switched on or off. In addition, voltage transients on the AC power line may appear on the DC output. If this possibility exists it is suggested that a clamp circuit be used.
DescriptionSMSC's COM20020 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 small 24 pin package, flexible microcontroller and media interfaces, eight- page message support, and extended temperature range of the COM20020 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 COM20020.
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 COM20020 the highest performance embedded communications device available. With only one COM20020 and one microcontroller, a complete communications node may be implemented.
COM20020 Data Sheet
