Chapter 4
Signal Connections
©
National Instruments Corporation
4-17
PCI-4451/4452/4453/4454 User Manual
Digital I/O Signal Connections (PCI-4451/4452 Only)
The digital I/O signals are DIO<0..7> and DGND. DIO<0..7> are the
signals making up the DIO port. DGND is the ground-reference signal for
the DIO port. You can program all lines individually to be inputs or outputs.
Figure 4-8 shows signal connections for three typical digital I/O
applications.
Figure 4-8.
Digital I/O Connections
Figure 4-8 shows DIO<0..3> configured for digital input and DIO<4..7>
configured for digital output. Digital input applications include receiving
TTL signals and sensing external device states such as the state of the
switch shown in Figure 4-8. Digital output applications include sending
TTL signals and driving external devices such as the LED shown in
Figure 4-8.
LED
+5 V
TTL Signal
+5 V
DIO<4..7>
DIO<0..3>
DGND
Switch
I/O Connector