SMSC COM20019I
Page 1
Rev. 04-15-05
DATASHEET
COM20019I
Low Cost ARCNET
(ANSI 878.1)
Controller with 2K x 8
On-Board RAM
Datasheet
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 -40
o
C to +85
o
C
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
ORDERING INFORMATION
Order Number(s):
COM20019I-LJP for 28 pin PLCC Package
COM20019I-HD for 48 pin TQFP Package
Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM
Rev. 04-15-05
Page 2
SMSC COM20019I
DATASHEET
80 Arkay Drive
Hauppauge,
NY
11788
(631)
435-6000
FAX (631) 273-3123
Copyright SMSC 2005. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete
information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no
responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without
notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information does
not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of SMSC
or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's standard
Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request.
SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure could cause
or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC and further
testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms of Sale
Agreement, may be obtained by visiting SMSC's website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems
Corporation ("SMSC"). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES
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NOT ANY REMEDY OF BUYER IS HELD TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM
SMSC COM20019I
Page 3
Rev. 04-15-05
DATASHEET
TABLE OF CONTENTS
Chapter 1
GENERAL DESCRIPTION..................................................................................................... 5
Chapter 2
PIN CONFIGURATIONS........................................................................................................ 6
Chapter 3
DESCRIPTION OF PIN FUNCTIONS.................................................................................... 8
Chapter 4
PROTOCOL DESCRIPTION ............................................................................................... 11
4.1
NETWORK PROTOCOL............................................................................................................................11
4.2
DATA RATES.............................................................................................................................................11
4.3
NETWORK RECONFIGURATION.............................................................................................................11
4.4
BROADCAST MESSAGES........................................................................................................................12
4.5
EXTENDED TIMEOUT FUNCTION ...........................................................................................................12
4.5.1
Response Time ...................................................................................................................................12
4.5.2
Idle Time .............................................................................................................................................12
4.5.3
Reconfiguration Time ..........................................................................................................................13
4.6
LINE PROTOCOL ......................................................................................................................................13
4.6.1
Invitations To Transmit........................................................................................................................13
4.6.2
Free Buffer Enquiries ..........................................................................................................................13
4.6.3
Data Packets.......................................................................................................................................13
4.6.4
Acknowledgements .............................................................................................................................14
4.6.5
Negative Acknowledgements..............................................................................................................14
Chapter 5
SYSTEM DESCRIPTION ..................................................................................................... 15
5.1
MICROCONTROLLER INTERFACE..........................................................................................................15
5.1.1
High Speed CPU Bus Timing Support ................................................................................................18
5.2
TRANSMISSION MEDIA INTERFACE ......................................................................................................19
5.2.1
Backplane Configuration .....................................................................................................................19
5.2.2
Differential Driver Configuration ..........................................................................................................20
5.2.3
Programmable TXEN Polarity .............................................................................................................20
Chapter 6
FUNCTIONAL DESCRIPTION............................................................................................. 23
6.1
MICROSEQUENCER.................................................................................................................................23
6.2
INTERNAL REGISTERS............................................................................................................................24
6.2.1
Interrupt Mask Register (IMR) .............................................................................................................24
6.2.2
Data Register ......................................................................................................................................24
6.2.3
Tentative ID Register ..........................................................................................................................25
6.2.4
Node ID Register.................................................................................................................................25
6.2.5
Next ID Register..................................................................................................................................25
6.2.6
Status Register....................................................................................................................................25
6.2.7
Diagnostic Status Register..................................................................................................................26
6.2.8
Command Register .............................................................................................................................26
6.2.9
Address Pointer Registers ..................................................................................................................26
6.2.10
Configuration Register.....................................................................................................................26
6.2.11
Sub-Address Register .....................................................................................................................26
6.2.12
Setup 1 Register..............................................................................................................................26
6.2.13
Setup 2 Register..............................................................................................................................27
6.3
INTERNAL RAM ........................................................................................................................................34
6.3.1
Sequential Access Memory.................................................................................................................34
6.3.2
Access Speed .....................................................................................................................................35
6.4
SOFTWARE INTERFACE..........................................................................................................................35
6.4.1
Selecting RAM Page Size ...................................................................................................................35
6.4.2
Transmit Sequence .............................................................................................................................37
6.4.3
Receive Sequence ..............................................................................................................................38
6.5
COMMAND CHAINING..............................................................................................................................39
6.5.1
Transmit Command Chaining .............................................................................................................40
6.5.2
Receive Command Chaining ..............................................................................................................40
6.6
RESET DETAILS .......................................................................................................................................41
6.6.1
Internal Reset Logic ............................................................................................................................41
6.7
INITIALIZATION SEQUENCE....................................................................................................................41
6.7.1
Bus Determination...............................................................................................................................41
6.8
IMPROVED DIAGNOSTICS ......................................................................................................................42
6.8.1
Normal Results:...................................................................................................................................43
Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM
Rev. 04-15-05
Page 4
SMSC COM20019I
DATASHEET
6.8.2
Abnormal Results:...............................................................................................................................43
6.9
OSCILLATOR ............................................................................................................................................43
Chapter 7
OPERATIONAL DESCRIPTION .......................................................................................... 45
7.1
MAXIMUM GUARANTEED RATINGS*......................................................................................................45
7.2
DC ELECTRICAL CHARACTERISTICS ....................................................................................................45
Chapter 8
TIMING DIAGRAMS............................................................................................................. 48
Chapter 9
Package Outlines ................................................................................................................. 60
9.1
28 Pin PLCC Package Outline and Parameters.........................................................................................60
9.2
48 Pin TQFP Package Outline and Parameters.........................................................................................61
Chapter 10
APPENDIX A........................................................................................................................ 62
10.1
NOSYNC Bit ...........................................................................................................................................62
10.2
EF Bit......................................................................................................................................................62
Chapter 11
APPENDIX B:....................................................................................................................... 65
LIST OF FIGURES
Figure 3.1 - COM20019I OPERATION ........................................................................................................................10
Figure 5.1 - MULTIPLEXED, 8051-LIKE BUS INTERFACE WITH RS-485 INTERFACE ............................................16
Figure 5.2 - NON-MULTIPLEXED, 6801-LIKE BUS INTERFACE WITH RS-485 INTERFACE...................................17
Figure 5.3 - HIGH SPEED CPU BUS TIMING - INTEL CPU MODE............................................................................18
Figure 5.4 - COM20019I NETWORK USING RS-485 DIFFERENTIAL TRANSCEIVERS...........................................20
Figure 5.5 - INTERNAL BLOCK DIAGRAM ..................................................................................................................21
Figure 6.1 - SEQUENTIAL ACCESS OPERATION ......................................................................................................34
Figure 6.2 - RAM BUFFER PACKET CONFIGURATION .............................................................................................37
Figure 6.3 - COMMAND CHAINING STATUS REGISTER QUEUE..............................................................................39
Figure 7.1 - AC MEASUREMENTS ..............................................................................................................................47
Figure 8.1 - MULTIPLEXED BUS, 68XX-LIKE CONTROL SIGNALS; READ CYCLE .................................................48
Figure 8.2 - MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; READ CYCLE .................................................49
Figure 8.3 - MULTIPLEXED BUS, 68XX-LIKE CONTROL SIGNALS; WRITE CYCLE................................................50
Figure 8.4 - MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; WRITE CYCLE................................................51
Figure 8.5 - NON-MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; READ CYCLE ........................................52
Figure 8.6 - NON-MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; READ CYCLE ........................................53
Figure 8.7 - NON-MULTIPLEXED BUS, 68XX-LIKE CONTROL SIGNALS; READ CYCLE ........................................54
Figure 8.8 - NON-MULTIPLEXED BUS, 68XX-LIKE CONTROL SIGNALS; READ CYCLE ........................................55
Figure 8.9 - NON-MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; WRITE CYCLE ......................................56
Figure 8.10 - NON-MULTIPLEXED BUS, 68XX-LIKE CONTROL SIGNALS; WRITE CYCLE ....................................57
Figure 8.11 - BACKPLANE MODE TRANSMIT OR RECEIVE TIMING.......................................................................58
Figure 8.12 - TTL INPUT TIMING ON XTAL1 PIN .......................................................................................................59
Figure 8.13 - RESET AND INTERRUPT TIMING ........................................................................................................59
Figure 10.1 - EFFECT OF THE EB BIT ON THE TA/RI BIT ........................................................................................63
Figure 11.1 - EXAMPLE OF INTERFACE CIRCUIT DIAGRAM TO ISA BUS .............................................................65
LIST OF TABLES
Table 5.1 - Typical Media .............................................................................................................................................22
Table 6.1 - Read Register Summary.............................................................................................................................23
Table 6.2 - Write Register Summary ............................................................................................................................24
Table 6.3 - Status Register ...........................................................................................................................................27
Table 6.4 - Diagnostic Status Register..........................................................................................................................28
Table 6.5 - Command Register.....................................................................................................................................29
Table 6.6 - Address Pointer High Register ....................................................................................................................30
Table 6.7 - Address Pointer Low Register.....................................................................................................................30
Table 6.8 - Sub Address Register.................................................................................................................................31
Table 6.9 - Configuration Register ................................................................................................................................31
Table 6.10 - Setup 1 Register .......................................................................................................................................32
Table 6.11 - Setup 2 Register .......................................................................................................................................33
Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM
SMSC COM20019I
Page 5
Rev. 04-15-05
DATASHEET
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.
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