National Instruments 6508 PCI-DIO-96 - Manual (Page 63)

Chapter 6 Programming
© National Instruments Corporation 6-17 PCI-DIO-96 User Manual
Figure 6-7. Control Word to Configure Port A as Mode 2 Bidirectional Data Bus
During a mode 2 data transfer, you can obtain the status of the
handshaking lines and interrupt signals by reading port C. The port C
status-word bit definitions for a mode 2 transfer are shown as follows.
Port C
PC <2..0>
1 = Input
0 = Output
D7 D6 D5 D4 D3 D2 D1 D0
1 1 X X X 1/0 1/0 1/0
Port B
1 = Input
0 = Output
Group B Mode
0 = Mode 0
1 = Mode 1