National Instruments PC-DIO-24/PnP user manual - page 6

Contents
PC-DIO-24/PnP User Manual vi
© National Instruments Corporation
Digital I/O Power-up State Selection........................................................................... 3-7
High DIO Power-up State..............................................................................3-7
Low DIO Power-up State...............................................................................3-9
Timing Specifications...................................................................................................3-10
Mode 1 Input Timing.....................................................................................3-12
Mode 1 Output Timing.................................................................................. 3-13
Mode 2 Bidirectional Timing.........................................................................3-14
Chapter 4
Theory of Operation
Functional Overview....................................................................................................4-1
Bus Transceivers............................................................................................4-2
Bus Interface..................................................................................................4-2
Interrupt Control Circuitry.............................................................................4-2
82C55A Programmable Peripheral Interface.................................................4-2
Digital I/O Connector.....................................................................................4-3
Appendix A
Specifications
Appendix B
OKI 82C55A Data Sheet
Appendix C
Register-Level Programming
Introduction..................................................................................................................C-1
Register Map................................................................................................................C-3
Register Description for the 82C55A.............................................................C-3
Register Description for the Interrupt Control Registers............................... C-5
Interrupt Control Register 1 (PnP Board Only)...............................C-6
Interrupt Control Register 2 (PnP Board Only)...............................C-7
Programming Considerations for the 82C55A.............................................................C-8
Modes of Operation for the 82C55A............................................................. C-8
Mode 0.............................................................................................C-8
Mode 1.............................................................................................C-8
Mode 2.............................................................................................C-9
Single Bit Set/Reset Feature............................................................C-9
Mode 0—Basic I/O........................................................................................C-9
Mode 0 Programming Example.......................................................C-10