Contents
PC-DIO-24/PnP User Manual
vi
©
National Instruments Corporation
High DIO Power-up State .............................................................................. 3-7
Low DIO Power-up State............................................................................... 3-9
Mode 1 Input Timing ..................................................................................... 3-12
Mode 1 Output Timing .................................................................................. 3-13
Mode 2 Bidirectional Timing......................................................................... 3-14
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 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
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 Programming Example....................................................... C-10