Network Card User Manual
Table Of Contents
- PC-DIO-24 User Manual
- Contents
- About This Manual
- Chapter 1 Introduction
- Chapter 2 Configuration and Installation
- Chapter 3 Theory of Operation
- Chapter 4 Register-Level Programming
- Appendix A Specifications
- Appendix B I/O Connector
- Appendix C OKI 82C55A Data Sheet*
- Appendix D Customer Communication
- Glossary
- Index
- Figures
- Figure 1-1. The Relationship between the Programming Environment, NI-DAQ, and Your Hardware
- Figure 2-1. PC-DIO-24 Parts Locator Diagram
- Figure 2-2. Example Base I/O Address Switch Settings
- Figure 2-3. Jumper Settings–PC6, PC4, PC2, and N/C
- Figure 2-4. Interrupt Jumper Setting for IRQ5 (Factory Setting)
- Figure 2-5. Digital I/O Connector Pin Assignments
- Figure 3-1. PC-DIO-24 Block Diagram
- Figure 4-1. Control-Word Formats
- Figure B-1. PC-DIO-24 I/O Connector
- Tables
- Table 2-1. PC-DIO-24 Factory-Set Jumper and Switch Settings
- Table 2-2. Port C Signal Assignments
- Table 4-1. PC-DIO-24 Address Map
- Table 4-2. Port C Set/Reset Control Words
- Table 4-3. Mode 0 I/O Configurations
- Table 4-4. Interrupt Enable Signals for All Mode Combinations
- Table A-1. Maximum Average Transfer Rates for the PC-DIO-24
© National Instruments Corporation 3-1 PC-DIO-24 User Manual
Chapter 3
Theory of Operation
This chapter contains a functional overview of the PC-DIO-24 board and explains the operation
of each functional unit making up the PC-DIO-24.
The block diagram in Figure 3-1 illustrates the key functional components of the PC-DIO-24
board.
I/O Connector
Interrupt
Control
Circuitry
82C55A
PPI
PC I/O
Channel
Control
Circuitry
Address
Decoder
Bus
Transceivers
PA
PB
PC
/
8
/
8
/
8
PC3
PC0
+5 V
PC I/O Channel
1 A Fuse
Figure 3-1. PC-DIO-24 Block Diagram
The PC I/O Channel consists of an address bus, a data bus, interrupt lines, and several control
and support signals. Control and data transfers to the system microprocessor are asynchronous.