COM20019I-HT datasheet(3/65 Pages) SMSC

3 / 65 page

Low Cost ARCNET (ANSI 878.1) Controller with 2K x 8 On-Board RAM

SMSC COM20019I

Page 3

Rev. 03-07-06

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

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