COM20020I Rev D
5Mbps ARCNET (ANSI
878.1) Controller with
2K x 8 On-Chip RAM
Datasheet
Product Features
New Features for Rev. D
−
Data Rates up to 5 Mbps
−
Programmable Reconfiguration Times
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 -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:
−
Traditional Hybrid Interface For Long
Distances up to Four Miles at 2.5 Mbps
−
RS485 Differential Driver Interface For Low
Cost, Low Power, High Reliability
28 Pin PLCC and 48 Pin TQFP Packages;
Lead-free RoHS Compliant Packages also
Available
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
ORDERING INFORMATION
Order Numbers:
COM20020ILJP for 28 pin PLCC package
COM20020I-DZD for 28 pin PLCC lead-free RoHS compliant package
COM20020I-HD for 48 pin TQFP package
COM20020I-HT for 48 pin TQFP lead-free RoHS compliant package
SMSC COM20020I Rev D
Page 1
Revision 12-05-06
DATASHEET
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
80 Arkay Drive
Hauppauge, NY 11788
(631) 435-6000
FAX (631) 273-3123
Copyright © 2006 SMSC or its subsidiaries. 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
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND
ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY
DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR
REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC
OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR 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.
Revision 12-05-06
Page 2
SMSC COM20020I Rev D
DATASHEET
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
Table of Contents
Chapter 1
Chapter 2
Chapter 3
Chapter 4
General Description................................................................................................................ 6
Pin Configurations .................................................................................................................. 7
Description of Pin Functions .................................................................................................. 9
Protocol Description ............................................................................................................. 12
4.1
Network Protocol ........................................................................................................................................12
4.2
Data Rates .................................................................................................................................................12
4.2.1
Selecting Clock Frequencies Above 2.5 Mbps....................................................................................12
4.3
Network Reconfiguration ............................................................................................................................13
4.4
Broadcast Messages..................................................................................................................................14
4.5
Extended Timeout Function .......................................................................................................................14
4.5.1
Response Time ...................................................................................................................................14
4.5.2
Idle Time .............................................................................................................................................14
4.5.3
Reconfiguration Time ..........................................................................................................................14
4.6
Line Protocol ..............................................................................................................................................14
4.6.1
Invitations To Transmit........................................................................................................................15
4.6.2
Free Buffer Enquiries ..........................................................................................................................15
4.6.3
Data Packets.......................................................................................................................................15
4.6.4
Acknowledgements .............................................................................................................................16
4.6.5
Negative Acknowledgements ..............................................................................................................16
Chapter 5
System Description .............................................................................................................. 17
5.1
Microcontroller Interface.............................................................................................................................17
5.1.1
High Speed CPU Bus Timing Support ................................................................................................20
5.2
Transmission Media Interface ....................................................................................................................21
5.2.1
Traditional Hybrid Interface .................................................................................................................21
5.2.2
Backplane Configuration .....................................................................................................................21
5.2.3
Differential Driver Configuration ..........................................................................................................23
5.2.4
Programmable TXEN Polarity .............................................................................................................23
Chapter 6
Functional Description.......................................................................................................... 26
6.1
Microsequencer..........................................................................................................................................26
6.2
Internal Registers .......................................................................................................................................27
6.2.1
Interrupt Mask Register (IMR) .............................................................................................................27
6.2.2
Data Register ......................................................................................................................................28
6.2.3
Tentative ID Register ..........................................................................................................................28
6.2.4
Node ID Register.................................................................................................................................28
6.2.5
Next ID Register..................................................................................................................................28
6.2.6
Status Register....................................................................................................................................29
6.2.7
Diagnostic Status Register ..................................................................................................................29
6.2.8
Command Register .............................................................................................................................29
6.2.9
Address Pointer Registers ..................................................................................................................29
6.2.10
Configuration Register.....................................................................................................................29
6.2.11
Sub-Address Register .....................................................................................................................29
6.2.12
Setup 1 Register..............................................................................................................................30
6.2.13
Setup 2 Register..............................................................................................................................30
6.3
Internal RAM ..............................................................................................................................................40
6.3.1
Sequential Access Memory.................................................................................................................40
6.3.2
Access Speed .....................................................................................................................................40
6.4
Software Interface ......................................................................................................................................40
6.4.1
Selecting RAM Page Size ...................................................................................................................41
6.4.2
Transmit Sequence .............................................................................................................................42
6.4.3
Receive Sequence ..............................................................................................................................44
6.5
Command Chaining....................................................................................................................................45
6.5.1
Transmit Command Chaining .............................................................................................................45
6.5.2
Receive Command Chaining ..............................................................................................................46
6.6
Reset Details..............................................................................................................................................47
6.6.1
Internal Reset Logic ............................................................................................................................47
6.7
Initialization Sequence ...............................................................................................................................47
6.7.1
Bus Determination...............................................................................................................................47
SMSC COM20020I Rev D
Page 3
Revision 12-05-06
DATASHEET
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
6.8
Improved Diagnostics.................................................................................................................................48
6.8.1
Normal Results:...................................................................................................................................48
6.8.2
Abnormal Results:...............................................................................................................................48
6.9
Oscillator ....................................................................................................................................................49
Chapter 7
7.1
7.2
Operational Description........................................................................................................ 50
Maximum Guaranteed Ratings* .................................................................................................................50
DC Electrical Characteristics......................................................................................................................50
Chapter 8
Timing Diagrams .................................................................................................................. 53
Chapter 9
Package Outlines ................................................................................................................. 66
Appendix A.................................................................................................................................................. 68
Appendix B - Example of Interface Circuit Diagram to ISA Bus ............................................................. 71
Appendix C - Software Identification of the COM20020 Rev B, Rev C and Rev D ................................ 72
List of Figures
Figure 2.1 - Pin Configuration - COM20020I 28-Pin PLCC ............................................................................................7
Figure 2.2 - Pin Configuration - COM20020I 48-Pin TQFP ............................................................................................8
Figure 3.1 - COM20020ID Operation ...........................................................................................................................11
Figure 5.1 – Multiplexed, 8051-Like Bus Interface with RS-485 Interface....................................................................18
Figure 5.2 – Non-Multiplexed, 6801-Like Bus Interface with RS-485 Interface ............................................................19
Figure 5.3 – High Speed CPU Bus Timing – Intel CPU Mode......................................................................................20
Figure 5.4 - COM20020ID Network Using RS-485 Differential Transceivers ...............................................................22
Figure 5.5 – Dipulse Waveform for Data of 1-1-0.........................................................................................................22
Figure 5.6 - Internal Block Diagram..............................................................................................................................24
Figure 6.1 - Sequential Access Operation.....................................................................................................................39
Figure 6.2 - RAM Buffer Packet Configuration .............................................................................................................42
Figure 6.3 – Command Chaining Status Register Queue..............................................................................................44
Figure 8.1 – Multiplexed Bus, 68XX-Like Control Signals; Read Cycle........................................................................53
Figure 8.2 – Multiplexed Bus, 80XX-Like Control Signals; Read Cycle........................................................................54
Figure 8.3 - Multiplexed Bus, 68XX-Like Control Signals; Write Cycle.........................................................................55
Figure 8.4 - Multiplexed Bus, 80XX-Like Control Signals; Write Cycle.........................................................................56
Figure 8.5 - Non-Multiplexed Bus, 80XX-Like Control Signals; Read Cycle.................................................................57
Figure 8.6 - Non-Multiplexed Bus, 80XX-Like Control Signals; Read Cycle.................................................................58
Figure 8.7 - Non-Multiplexed Bus, 68XX-Like Control Signals; Read Cycle.................................................................59
Figure 8.8 - Non-Multiplexed Bus, 68XX-Like Control Signals; Read Cycle.................................................................60
Figure 8.9 - Non-Multiplexed Bus, 80XX-Like Control Signals; Write Cycle.................................................................61
Figure 8.10 - Non-Multiplexed Bus, 68XX-Like Control Signals; Write Cycle ...............................................................62
Figure 8.11 - Normal Mode Transmit or Receive Timing..............................................................................................63
Figure 8.12 - Backplane Mode Transmit or Receive Timing ........................................................................................64
Figure 8.13 - TTL Input Timing on XTAL1 Pin..............................................................................................................65
Figure 8.14 - Reset and Interrupt Timing .....................................................................................................................65
Figure 9.1 - 28 Pin PLCC Package Dimensions...........................................................................................................66
Figure 9.2 - 48 Pin TQFP Package Outline..................................................................................................................67
Figure 0.1 - Effect of the EF Bit on the TA/RI Bit..........................................................................................................70
List of Tables
Table 5.1 - Typical Media.............................................................................................................................................24
Table 6.1 - Read Register Summary............................................................................................................................26
Table 6.2 - Write Register Summary ............................................................................................................................27
Table 6.3 - Status Register ...........................................................................................................................................31
Table 6.4 - Diagnostic Status Register..........................................................................................................................32
Table 6.5 - Command Register.....................................................................................................................................33
Table 6.6 - Address Pointer High Register ....................................................................................................................34
Table 6.7 - Address Pointer Low Register.....................................................................................................................34
Table 6.8 - Sub Address Register .................................................................................................................................34
Table 6.9 - Configuration Register ................................................................................................................................35
Revision 12-05-06
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SMSC COM20020I Rev D
DATASHEET
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
Table 6.10 - Setup 1 Register .......................................................................................................................................36
Table 6.11 - Setup 2 Register .......................................................................................................................................37
Table 9.1 - 48 Pin TQFP Package Parameters ............................................................................................................67
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 COM20020I Rev D
Page 5
Revision 12-05-06
DATASHEET
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