National Instruments PC-DIO-24 User manual

© Copyright 1989, 1995 National Instruments Corporation.
All Rights Reserved.
PC-DIO-24
User Manual
Digital I/O Board for the IBM PC/XT/AT
September 1995 Edition
Part Number 320288B-01

National Instruments Corporate Headquarters
6504 Bridge Point Parkway
Austin, TX 78730-5039
[phone]
Technical support fax: [phone]
[phone]
Branch Offices:
Australia 03 9 879 9422, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Canada (Ontario) 519 622 9310,
Canada (Québec) 514 694 8521, Denmark 45 76 26 00, Finland 90 527 2321, France 1 48 14 24 24,
Germany 089 741 31 30, Hong Kong 2645 3186, Italy 02 48301892, Japan 03 5472 2970, Korea 02 596 7456,
Mexico 5 202 2544, Netherlands 03480 33466, Norway 32 84 84 00, Singapore 2265886, Spain 91 640 0085,
Sweden 08 730 49 70, Switzerland 056 20 51 51, Taiwan 02 377 1200, U.K. 01635 523545

Limited Warranty
The PC-DIO-24 is warranted against defects in materials and workmanship for a period of one year from the date of
shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace
equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
The media on which you receive National Instruments software are warranted not to fail to execute programming
instructions, due to defects in materials and workmanship, for a period of 90 days from date of shipment, as
evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace software
media that do not execute programming instructions if National Instruments receives notice of such defects during
the warranty period. National Instruments does not warrant that the operation of the software shall be uninterrupted
or error free.
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the
outside of the package before any equipment will be accepted for warranty work. National Instruments will pay the
shipping costs of returning to the owner parts which are covered by warranty.
National Instruments believes that the information in this manual is accurate. The document has been carefully
reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments
reserves the right to make changes to subsequent editions of this document without prior notice to holders of this
edition. The reader should consult National Instruments if errors are suspected. In no event shall National
Instruments be liable for any damages arising out of or related to this document or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR
IMPLIED, AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. CUSTOMER'S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT
OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT
THERETOFORE PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR
DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR
CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of the
liability of National Instruments will apply regardless of the form of action, whether in contract or tort, including
negligence. Any action against National Instruments must be brought within one year after the cause of action
accrues. National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable
control. The warranty provided herein does not cover damages, defects, malfunctions, or service failures caused by
owner's failure to follow the National Instruments installation, operation, or maintenance instructions; owner's
modification of the product; owner's abuse, misuse, or negligent acts; and power failure or surges, fire, flood,
accident, actions of third parties, or other events outside reasonable control.
Copyright
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or
mechanical, including photocopying, recording, storing in an information retrieval system, or translating, in whole or
in part, without the prior written consent of National Instruments Corporation.
Trademarks
LabVIEW®and NI-DAQ®are trademarks of National Instruments Corporation.
Product and company names listed are trademarks or trade names of their respective companies.

WARNING REGARDING MEDICAL AND CLINICAL USE
OF NATIONAL INSTRUMENTS PRODUCTS
National Instruments products are not designed with components and testing intended to ensure a level of reliability
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products involving
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by errors on the
part of the user or application designer. Any use or application of National Instruments products for or involving
medical or clinical treatment must be performed by properly trained and qualified medical personnel, and all
traditional medical safeguards, equipment, and procedures that are appropriate in the particular situation to prevent
serious injury or death should always continue to be used when National Instruments products are being used.
National Instruments products are NOT intended to be a substitute for any form of established process, procedure, or
equipment used to monitor or safeguard human health and safety in medical or clinical treatment.

FCC/DOC Radio Frequency Interference Compliance
This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the
instructions in this manual, may cause interference to radio and television reception. This equipment has been tested
and found to comply with the following two regulatory agencies:
Federal Communications Commission
This device complies with Part 15 of the Federal Communications Commission (FCC) Rules for a Class A digital
device. Operation is subject to the following two conditions:
1. This device may not cause harmful interference in commercial environments.
2. This device must accept any interference received, including interference that may cause undesired operation.
Canadian Department of Communications
This device complies with the limits for radio noise emissions from digital apparatus set out in the Radio
Interference Regulations of the Canadian Department of Communications (DOC).
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables aux appareils
numériques de classe A prescrites dans le règlement sur le brouillage radioélectrique édicté par le ministère des
communications du Canada.
Instructions to Users
These regulations are designed to provide reasonable protection against harmful interference from the equipment to
radio reception in commercial areas. Operation of this equipment in a residential area is likely to cause harmful
interference, in which case the user will be required to correct the interference at his own expense.
There is no guarantee that interference will not occur in a particular installation. However, the chances of
interference are much less if the equipment is installed and used according to this instruction manual.
If the equipment does cause interference to radio or television reception, which can be determined by turning the
equipment on and off, one or more of the following suggestions may reduce or eliminate the problem.
• Operate the equipment and the receiver on different branches of your AC electrical system.
• Move the equipment away from the receiver with which it is interfering.
• Reorient or relocate the receiver’s antenna.
• Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated with a
cheater plug.
Notice to user: Changes or modifications not expressly approved by National Instruments could void the user’s
authority to operate the equipment under the FCC Rules.
If necessary, consult National Instruments or an experienced radio/television technician for additional suggestions.
The following booklet prepared by the FCC may also be helpful: How to Identify and Resolve Radio-TV
Interference Problems. This booklet is available from the U.S. Government Printing Office, Washington, DC
20402, Stock Number 004-000-00345-4.

© National Instruments Corporation vii PC-DIO-24 User Manual
Contents
About This Manual.............................................................................................................xi
Organization of This Manual .........................................................................................xi
Conventions Used in This Manual.................................................................................xii
National Instruments Documentation ............................................................................xii
Related Documentation..................................................................................................xiii
Customer Communication .............................................................................................xiii
Chapter 1
Introduction ..........................................................................................................................1-1
About the PC-DIO-24 ....................................................................................................1-1
What You Need to Get Started ......................................................................................1-2
Software Programming Choices ....................................................................................1-2
LabVIEW and LabWindows/CVI Application Software ..................................1-2
NI-DAQ Driver Software...................................................................................1-3
Register-Level Programming.............................................................................1-4
Optional Equipment .......................................................................................................1-4
Custom Cables ...................................................................................................1-4
Unpacking ......................................................................................................................1-6
Chapter 2
Configuration and Installation ......................................................................................2-1
Board Configuration ......................................................................................................2-1
Base I/O Address Settings..................................................................................2-2
Interrupt Selection..............................................................................................2-4
Interrupt Enable Settings........................................................................2-4
Interrupt Level Settings..........................................................................2-4
Installation......................................................................................................................2-5
Signal Connections ........................................................................................................2-6
I/O Connector Pin Description...........................................................................2-6
Signal Connection Descriptions.........................................................................2-7
Port C Pin Assignments .........................................................................2-7
Timing Specifications ........................................................................................2-8
Mode 1 Input Timing .............................................................................2-9
Mode 1 Output Timing ..........................................................................2-10
Mode 2 Bidirectional Timing.................................................................2-11
Chapter 3
Theory of Operation ..........................................................................................................3-1
Address Decoder............................................................................................................3-2
Bus Transceivers............................................................................................................3-2
PC I/O Channel Control Circuitry .................................................................................3-2
82C55A Programmable Peripheral Interface ................................................................3-2
Interrupt Control Circuitry.............................................................................................3-2
Digital I/O Connector.....................................................................................................3-2

Contents
PC-DIO-24 User Manual viii © National Instruments Corporation
Chapter 4
Register-Level Programming .........................................................................................4-1
Introduction....................................................................................................................4-1
82C55A Modes of Operation.........................................................................................4-1
Mode 0 ...............................................................................................................4-2
Mode 1 ...............................................................................................................4-2
Mode 2 ...............................................................................................................4-2
Single Bit Set/Reset Feature ..............................................................................4-2
Register Map..................................................................................................................4-3
Register Descriptions .....................................................................................................4-3
Single Bit Set/Reset Feature ..............................................................................4-4
Programming Considerations.........................................................................................4-5
Mode 0–Basic I/O ..............................................................................................4-5
Mode 0 Programming Example .............................................................4-6
Mode 1–Strobed Input .......................................................................................4-7
Mode 1 Input Programming Example....................................................4-9
Mode 1–Strobed Output.....................................................................................4-9
Mode 1 Output Programming Example.................................................4-11
Mode 2–Bidirectional Bus .................................................................................4-12
Mode 2 Programming Example .............................................................4-13
Interrupt Programming Examples......................................................................4-14
Interrupt Handling..........................................................................................................4-15
Appendix A
Specifications........................................................................................................................A-1
Appendix B
I/O Connector.......................................................................................................................B-1
Appendix C
OKI 82C55A Data Sheet...................................................................................................C-1
Appendix D
Customer Communication...............................................................................................D-1
Glossary............................................................................................................................Glossary-1
Index ..................................................................................................................................Index-1

Contents
© National Instruments Corporation ix PC-DIO-24 User Manual
Figures
Figure 1-1. The Relationship between the Programming Environment, NI-DAQ, and
Your Hardware...................................................................................................1-3
Figure 2-1. PC-DIO-24 Parts Locator Diagram ...................................................................2-2
Figure 2-2. Example Base I/O Address Switch Settings .....................................................2-3
Figure 2-3. Jumper Settings–PC6, PC4, PC2, and N/C........................................................2-4
Figure 2-4. Interrupt Jumper Setting for IRQ5 (Factory Setting) ........................................2-4
Figure 2-5. Digital I/O Connector Pin Assignments ............................................................2-6
Figure 3-1. PC-DIO-24 Block Diagram ...............................................................................3-1
Figure 4-1. Control-Word Formats.......................................................................................4-4
Figure B-1. PC-DIO-24 I/O Connector.................................................................................B-1
Tables
Table 2-1. PC-DIO-24 Factory-Set Jumper and Switch Settings........................................2-1
Table 2-2. Port C Signal Assignments ...............................................................................2-7
Table 4-1. PC-DIO-24 Address Map...................................................................................4-3
Table 4-2. Port C Set/Reset Control Words ........................................................................4-5
Table 4-3. Mode 0 I/O Configurations................................................................................4-6
Table 4-4. Interrupt Enable Signals for All Mode Combinations .......................................4-16
Table A-1. Maximum Average Transfer Rates for the PC-DIO-24.....................................A-2

© National Instruments Corporation xi PC-DIO-24 User Manual
About This Manual
This manual describes the mechanical and electrical aspects of the PC-DIO-24 and contains
information concerning its operation and programming. The PC-DIO-24 is a 24-bit parallel,
digital I/O interface designed around an 82C55A programmable peripheral interface (PPI). The
PC-DIO-24 is a member of the National Instruments PC Series of PC I/O Channel expansion
boards for the IBM PC computer family. These boards are designed for low-cost data acquisition
and control for applications in laboratory testing, production testing, and industrial process
monitoring and control.
This manual describes installation, basic programming considerations, and theory of operation
for the PC-DIO-24. The example programs included are written in C.
Organization of This Manual
The PC-DIO-24 User Manual is organized as follows:
• Chapter 1, Introduction, describes the PC-DIO-24, lists what you need to get started,
describes software programming choices, optional equipment, and custom cables, and
explains how to unpack the PC-DIO-24.
• Chapter 2, Configuration and Installation, describes how to configure and install the
PC-DIO-24, including I/O connector signal descriptions, handshake timing diagrams, and
cabling instructions.
• Chapter 3, Theory of Operation, contains a functional overview of the PC-DIO-24 board and
explains the operation of each functional unit making up the PC-DIO-24.
• Chapter 4, Register-Level Programming, describes in detail the address and function of each
of the PC-DIO-24 control and status registers. This chapter also includes important
information related to register-level programming the PC-DIO-24.
• Appendix A, Specifications, lists the specifications for the PC-DIO-24 board.
• Appendix B, I/O Connector, describes the pinout and signal names for the I/O connector on
the PC-DIO-24.
• Appendix C, OKI 82C55A Data Sheet,contains the manufacturer data sheet for the
OKI 82C55A (OKI Semiconductor) CMOS programmable peripheral interface. This
interface is used on the PC-DIO-24 board.
• Appendix D, Customer Communication, contains forms you can use to request help from
National Instruments or to comment on our products.
• The Glossary contains an alphabetical list and description of terms used in this manual,
including abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms.

About This Manual
PC-DIO-24 User Manual xii © National Instruments Corporation
• The Index alphabetically lists the topics in this manual, including the page where you can
find each one.
Conventions Used in This Manual
The following conventions are used in this manual.
bold Bold text denotes menus, menu items, or dialog box buttons or options.
bold italic Bold italic text denotes a note, caution, or warning.
italic Italic text denotes emphasis, a cross reference, or an introduction to a key
concept.
monospace Lowercase text in this font denotes text or characters that are to be literally
input from the keyboard, sections of code, programming examples, and
syntax examples. This font is also used for the proper names of disk
drives, paths, directories, programs, subprograms, subroutines, device
names, functions, variables, filenames, and extensions, and for statements
and comments taken from program code.
NI-DAQ NI-DAQ refers to the NI-DAQ software for PC compatibles unless
otherwise noted.
PC PC refers to the IBM PC/XT, the IBM PC AT, and compatible computers
unless otherwise noted.
SCXI SCXI stands for Signal Conditioning eXtensions for Instrumentation and
is a National Instruments product line designed to perform front-end signal
conditioning for National Instruments plug-in DAQ boards.
< > Angle brackets containing numbers separated by an ellipses represent a
range, signal, or port (for example, ACH<0..7> stands for ACH0 through
ACH7).
Abbreviations, acronyms, metric prefixes, mnemonics, and symbols are listed in the Glossary.
National Instruments Documentation
The PC-DIO-24 User Manual is one piece of the documentation set for your data acquisition
(DAQ) system. You could have any of several types of manuals, depending on the hardware and
software in your system. Use the different types of manuals you have as follows:
•Getting Started with SCXI—If you are using SCXI, this is the first manual you should read.
It gives an overview of the SCXI system and contains the most commonly needed
information for the modules, chassis, and software.