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
Chapter 4 Register-Level Programming
© National Instruments Corporation 4-3 PC-DIO-24 User Manual
Register Map
The following table lists the address map for the PC-DIO-24. The registers PORTA, PORTB,
PORTC, and CNFG are 8-bit registers in the 82C55A.
Table 4-1. PC-DIO-24 Address Map
Register Offset Address
(Hex)
Size Type
PORTA
PORTB
PORTC
CNFG
0x00
0x01
0x02
0x03
8-bit
8-bit
8-bit
8-bit
Read-and-write
Read-and-write
Read-and-write
Write-Only
Note: A number preceded by 0x is a hexadecimal number.
Register Descriptions
Figure 4-1 shows the two control-word formats used to completely program the 82C55A. The
Control Word Flag determines which control-word format is being programmed. When the
Control Word Flag is 1, bits 0 through 6 determine the I/O characteristics of the 82C55A ports
and the mode in which they are operating (that is, mode 0, mode 1, or mode 2). When the
Control Word Flag is 0, bits 3 through 0 determine the bit set/reset format of port C.
Warning: During programming, note that each time a port is configured, output ports A
and C are reset to 0, and output port B is undefined.