Mode 0-Basic I/O; Single Bit Set/Reset Feature; Table C-3. Mode 0 I/O Configurations - National Instruments PC-DIO-24/PnP User Manual

Mode 0—Basic I/O
Control Word
Number 76543210
0 10000000
1 10000001
2 10000010
3 10000011
4 10001000
5 10001001
6 10001010
7 10001011
8 10010000
© National Instruments Corporation
Mode 2
Use this mode for communication over a bidirectional 8-bit bus.
Handshaking signals are used in a manner similar to mode 1. Mode 2 is
available for use in group A only (port A and the upper portion of
port C). Other features of this mode include the following:
• One 8-bit bidirectional port (port A) and a 5-bit control/status port
(port C).
• Latched inputs and outputs.
• Interrupt generation and enable/disable functions.

Single Bit Set/Reset Feature

You can set or reset any of the eight bits of port C with one control
word. This feature generates control signals for port A and port B when
these ports are operating in mode 1 or mode 2.
Use mode 0 for simple I/O functions (no handshaking) for each of the
three ports. You can assign each port as an input or an output port. The
16 possible I/O configurations are shown in Table C-3. Notice that bit 7
of the control word is set when programming the mode of operation for
each port.

Table C-3. Mode 0 I/O Configurations

Bit
Port A
Output
Output
Output
Output
Output
Output
Output
Output
Input
Appendix C
Group A
1
Port C
Output
Output
Output
Output
Input
Input
Input
Input
Output
C-9
Register-Level Programming
Group B
Port B Port C
Output Output
Output Input
Input Output
Input Input
Output Output
Output Input
Input Output
Input Input
Output Output
PC-DIO-24/PnP User Manual
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