Chapter 3
Signal Connections
©
National Instruments Corporation
3-7
PCI-DIO-96/PXI-6508/PCI-6503 User Manual
Table 3-2 describes the PCI-6503 signals.
Port C Pin Assignments
The signals assigned to port C vary depending on how the 82C55A is
configured. In mode 0—or no handshaking configuration—port C is
configured as two 4-bit I/O ports. In modes 1 and 2—or handshaking
configuration—port C is used for status and handshaking signals with any
leftover lines available for general-purpose I/O. Table 3-3 summarizes the
port C signal assignments for each configuration. You can also use ports A
and B in different modes; the table does not show every possible
combination. Consult Appendix B,
for register-level programming information.
Table 3-2.
PCI-6503 Signal Descriptions
Pin
Signal Name
Alternate
Port ID
†
Description
1, 3, 5, 7, 9, 11, 13, 15
PC<7..0>
2
Port C—Bidirectional data lines
for port C. PC7 is the MSB, PC0
is the LSB.
17, 19, 21, 23, 25, 27,
29, 31
PB<7..0>
1
Port B—Bidirectional data lines
for port B. PB7 is the MSB, PB0
is the LSB.
33, 35, 37, 39, 41, 43,
45, 47
PA<7..0>
0
Port A—Bidirectional data lines
for port B. PA7 is the MSB, PA0
is the LSB.
49
+5 V
—
+5 Volts—This pin is fused for
up to 1 A at +4.65 to 5.25 V.
All even-numbered pins
GND
—
Ground—These signals are
connected to the computer
ground reference.
†
This document refers to the 82C55 ports as A, B, and C. NI-DAQmx, Traditional NI-DAQ (Legacy), and LabVIEW
documentation use numbers to identify ports. For example, this manual uses port A to refer to the first port of the 82C55A.
NI-DAQmx, Traditional NI-DAQ (Legacy), LabWindows/CVI, LabVIEW, or other application software documentation,
however, refer to this port as
0
. The Alternate Port ID column shows the correlation between the different port names.
