National Instruments PCI-1200 Manual Do Utilizador
Chapter 3
Signal Connections
© National Instruments Corporation
3-17
Logical Inputs and Outputs
•
Absolute max voltage rating
–0.5 to +5.5 V with respect to DGND
•
Digital I/O lines:
–
Input logic low voltage
–0.3 V min
0.8 V max
–
Input logic high voltage
2.2 V min
5.3 V max
–
Output logic low voltage
—
0.4 V max
(at output current = 2.5 mA)
–
Output logic high voltage
3.7 V min
—
(at output current = –2.5 mA)
–
Input leakage current
–1 µA min
1 µA max
(0 < V
in
< 5 V)
Figure 3-8 illustrates signal connections for three typical digital I/O
applications.
applications.
Figure 3-8. Digital I/O Connections
In Figure 3-8, port A is configured for digital output, and ports B and C are
configured for digital input. Digital input applications include receiving
TTL signals and sensing external device states such as the switch in
configured for digital input. Digital input applications include receiving
TTL signals and sensing external device states such as the switch in
TTL Signal
13
DGND
I/O Connector
PCI-1200
30 PC0
22 PB0
+5 V
+5 V
LED
14 PA0
Port A
PA<7..0>
Port B
PB<7..0>
Port C
PC<7..0>