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THE UNIVERSITY OF MICHIGAN, Memorandum 15, A 201A DATA COMMUNICATION ADAPTOR FOR THE PDP-8: PRELIMINARY ENGINEERING DESIGN REPORT

IP.com Disclosure Number: IPCOM000128386D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Sep-15
Document File: 33 page(s) / 96K

Publishing Venue

Software Patent Institute

Related People

Wood, David E.: AUTHOR [+3]

Abstract

This report discusses the design and use of equipment built for data communication to and from the PDP-8 through a 01A data set. The purpose of the data communication interface is to allow a PDP-8 to send and receive digital data through a 201A data set in a half-duplex mode. The 201A data set operates serially at a rate of 2000 bits per second, with the transmit clocks supplied by the data set. In the receive mode, the data set achieves bit synchronization, and provides a receive clocking signal to the interface. The interface provides the character synchronization at the start of a message and then transfers successive characters in parallel to the PDP-8. The interface stores and retrieves characters from the PDP-8 memory through the data-break facility, while achieving control communication with the PDP-8 through the interrupt and programmed data transfer modes.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

[ title ] THE UNIVERSITY OF MICHIGAN, Memorandum 15, A 201A DATA COMMUNICATION ADAPTOR FOR THE PDP-8: PRELIMINARY ENGINEERING DESIGN REPORT

David E. Wood CONCOMP: Research in Conversational Use of Computers
F. H. Westervelt, Project Director ORA Project 07449 supported by, ADVANCED RESEARCH PROJECTS AGENCY, DEPARTMENT OF DEFENSE, WASHINGTON, D.C.

CONTRACT NO. DA-49-083 ORA-3050 ARPA ORDER NO 716 administered through: OFFICE OF RESEARCH ADMINISTRATION ANN ARBOR, February 1968

TABLE OF CONTENTS

INTRODUCTION.....1
DESIGN OBJECTIVES.....2
SYSTEM DESCHIPTION.....3
PROGRAMMING AND CONTROL CONSIDERATIONS.....7
A DATA FORMAT SCHEME.....14
DETAILED LINE ADAPTOR LOGIC.....16

Serial-Deserializer Register.....18
Clock Gating.....18
SDR Pulse Gating.....18
Data Set Signals.....22
SDR Serial Input/Output Gating.....22
Transmit/Receive State Gating.....22
Control Register 2.....22
Frame Counter.....27
State Synchronization.....27
Text State and Sync Detection.....27
Parity Gating.....31
Clear- and Request-to-Send Gating.....31
Character Service Interrupt Flag.....31
Status Indicators.....35
Control Word 1 EAC Gating.....35
Miscellaneous Pulses.....35
APPENDIX I.....I-i
APPENDIX II.....II-i
APPENDIX III.....III-i

University of Michigan Page 1 Feb 01, 1968

Page 2 of 33

THE UNIVERSITY OF MICHIGAN, Memorandum 15, A 201A DATA COMMUNICATION ADAPTOR FOR THE PDP-8:

PRELIMINARY ENGINEERING DESIGN REPORT

LIST OF DIAGRAMS

1. SDR Register.....19
2. Clock Gating.....20
3. SDR Pulse Gating.....21
4. Data Set/Interface Cable Assignment.....23
5. SDR Serial I/O Gating.....24
6. Transmit/Receive State Gating.....25
7. Control Register 2 (Frame Size).....26
8. Frame Counter.....28
9. State Synchronization.....29
10. Text State and Sync Detection.....30
11. Parity Gating.....32
12. Clear- and Request-to-Send Gating.....33
13. Character Service Interrupt Flag.....34
14. Status Indicators.....36
15. Control Word 1 EAC Gating.....37
16. Miscellaneous Pulses.....38

LIST OF FIGURES

1. 201A Communication Link.....4
2. 201A Line Adaptor Control.....5
3. Bit Assignment of Control Words.....9
4. Graphical Presentation of a Message Exchange Viewed from the PDP-8.....17

LIST OF TABLES

I Control-Character Definitions.....14

INTRODUCTION

This report discusses the design and use of equipment built for data communication to and from the PDP-8 through a 01A data set. The purpose of the data communication interface is to allow a PDP-8 to send and receive digital data through a 201A data set in a half-duplex mode. The 201A data set operates serially at a rate of 2000 bits per second, with the transmit clocks supplied by the data set. In the receive mode, the data set achieves bit synchronization, and provides a receive clocking signal to the interface. The interface provides the character synchronization at the start of a message and then transfers successive characters in parallel to

University of Michigan Page 2 Feb...