Appendix B
Register-Level Programming — Port C Status-Word Bit Definitions for Input (Ports A and B)
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National Instruments Corporation
B-23
PCI-DIO-96/PXI-6508/PCI-6503 User Manual
Mode 1—Strobed Output
Note
For mode 1 examples, you must configure the don’t care bits appropriately in the
control word if you want to use the other ports in combination with the example.
Figure B-7 shows the control word written to the Configuration Register to configure port A
for output in mode 1. You can use bits PC4 and PC5 of port C as extra input or output lines.
Figure B-7.
Control Word to Configure Port A for Mode 1 Output
Figure B-8 shows the control word written to the Configuration Register to configure port B
for output in mode 1. Notice that port B does not have extra input or output lines left from
port C when ports A and B are both configured for handshaking.
Figure B-8.
Control Word to Configure Port B for Mode 1 Output
During a mode 1 data write transfer, you can obtain the status of the handshaking lines and
interrupt signals by reading port C. Notice that the bit definitions are different for a write and
a read transfer.
Port C bits PC4 and PC5
1 = Input
0 = Output
D7
D6
D5
D4
D3
D2
D1
D0
1
0
1
0
1/0
X
X
X
D7
D6
D5
D4
D3
D2
D1
D0
1
X
X
X
X
1
X
0