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NI USB-6000 User Guide
Digital I/O
The NI USB-6000 has four digital lines, P0.<0..3>. D GND is the ground-reference signal for
digital I/O. You can individually program each line as input or output.
All digital I/O updates and samples are software-timed.
Figure 8 shows P0.<0..3> connected to signals configured as digital inputs and digital outputs.
Figure 8.
Example of Connecting a Load
Caution
Exceeding the maximum input voltage ratings or maximum output
ratings, which are listed in the
NI USB-6000 Specifications
document, can damage
the device and the computer. National Instruments is
not
liable for any damage
resulting from such signal connections.
Power-On States
At system startup and reset, the hardware sets all DIO lines to high-impedance inputs. The DAQ
device does not drive the signal high or low. Each line has a weak pull-down resistor connected
to it.
Source/Sink Information
The default configuration of the digital I/O ports is active drive, allowing 3.3 V operation, with
a source/sink current limit of ±4 mA.
1
P0.0 configured as a
digital input
receiving a 0 V or 5 V signal from a switch
2
P0.1 configured as an
active drive digital output
driving an LED
3
P0.2 configured as a
digital input
receiving a TTL signal
4
P0.3 configured as an
open collector digital output
driving an LED
S
witch
I/O Connector
D GND
P0.0
P0.1
P0.2
P0.
3
+5 V
+5 V
LED
LED
4
3
2
NI U
S
B-6000
1
