Chapter 6 Programming
©
National Instruments Corporation 6-7 PCI-DIO-96 User Manual
This manual also differs from the NI-DAQ, ComponentWorks,
LabWindows/CVI, and LabVIEW documentation by using different
terminology to describe the 82C55A configurations. Refer to Port C Pin
Assignments in Chapter 3, Signal Connections, for more information.
Programming Considerations for the 82C55A

Modes of Operation

The three basic modes of operation for the 82C55A are as follows:
• Mode 0—Basic I/O
• Mode 1—Strobed I/O
• Mode 2—Bidirectional bus
The 82C55A also has a single bit set/reset feature for port C, which is
programmed by the 8-bit control word. For additional information, refer
to Appendix B, MSM82C55A Data Sheet.

Mode 0

This mode can be used for simple input and output operations for each
port. No handshaking is required; a specified port simply writes to or
reads from data.
Table 6-1. Port Identification
ComponentWorks, LabVIEW,
LabWindows/CVI, and NI-DAQ PCI-DIO-96 User Manual
0
1
2
3
4
5
6
7
8
9
10
11
PPI A Port A
PPI A Port B
PPI A Port C
PPI B Port A
PPI B Port B
PPI B Port C
PPI C Port A
PPI C Port B
PPI C Port C
PPI D Port A
PPI D Port B
PPI D Port C