Chapter 3
Signal Connections
©
National Instruments Corporation
3-9
PCI-DIO-96/PXI-6508/PCI-6503 User Manual
Figure 3-4 depicts signal connections for three typical digital I/O
applications.
Figure 3-4.
Digital I/O Connections Block Diagram
In Figure 3-4, port A of one PPI is configured for digital output, and port B
is configured for digital input. Digital input applications include receiving
TTL signals and sensing external device states such as the state of the
switch in Figure 3-4. Digital output applications include sending TTL
signals and driving external devices such as the LED shown in Figure 3-4.
41
43
45
47
67
69
71
73
50, 100
GND
Switch
I/O Connector
+5 V
+5 V
LED
TTL Signal
DIO Board
Port A
PA<3..0>
Port B
PB<7..4>