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Chapter 4 Signal Connections
PCI-6023E/6024E/6025E User Manual 4-22
©
National Instruments Corporation
switch shown in the figure. Digital output applications include sending
TTL signals and driving external devices such as the LED shown in the
figure.
PCI-6025E Only
The PCI-6025E board uses an 82C55A PPI to provide an additional 24
lines of digital I/O that represent three 8-bit ports: PA, PB, and PC. Each
port can be programmed as an input or output port.
Figure 4-11 depicts signal connections for three typical digital I/O
applications.
Figure 4-11.
Digital I/O Connections Block Diagram
GND
DIO Board
Switch
I/O Connector
+5 V
+5 V
LED
Port B
PB<7..4>
Port A
PA<3..0>
TTL Signal
PCI.book Page 22 Wednesday, September 16, 1998 9:09 AM