National Instruments PCI-1200 用户手册

© National Instruments Corporation

•

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.

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 

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>