National Instruments NI USB-6009 User Manual

Figure 14 shows P0.<0..7> connected to example signals configured as 
digital inputs and digital outputs. You can configure P1.<0..3> similarly.

Figure 14.  Example of Connecting a Load

Exceeding the maximum input voltage ratings or maximum output ratings, which 

are listed in the 

 section, can damage the device and the computer. National 

Instruments is not liable for any damage resulting from such signal connections.

The default configuration of the NI USB-6008/6009 DIO ports is open 
collector, allowing 5 V operation, with an onboard 4.7 k

Ω pull-up resistor. 

An external user-provided pull-up resistor can be added to increase the 
source current drive up to a 8.5 mA limit per line as shown in Figure 15. 

The NI USB-6009 ports can also be configured as active drive using the 
NI-DAQmx API, allowing 3.3 V operation with a source/sink current limit 
of ±8.5 mA. Refer to the NI-DAQmx Help for more information about how 
to set the DIO configuration.

1

P0.0 configured as an open collector digital output driving a LED

2

P0.2 configured as a active drive digital output driving a LED

3

P0.4 configured as a digital input receiving a TTL signal from a gated invertor

4

P0.7 configured as a digital input receiving a 0 V or 5 V signal from a switch

+5 V

LED

Switch

I/O Connector

 GND

P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7

+5 V

LED

1

2

3

4

TTL Signal