When I Connect DPULL to +5V on my DIO Board, the Data Lines Never Go Low Hardware: Digital I/O (DIO)
Problem: When the DPULL line is not used, everything works as expected. When I connect the DPULL input to +5V, the data lines never go low. Why is this? Solution: Make sure that you are actually driving the lines low when you want them to go low. Specifically, connect a line to ground (e.g., the ground pin on the board) for testing purposes. If a line is left open (i.e., not connected to anything), it will remain high since the DPULL is pulling all the lines to a default state of +5V. Another potential problem is the 100kW internal pull-up resistor is too strong (too small) and whatever is connected to the lines is not able drive the pins low. See the link below for more information regarding this issue: Related Links: NI Developer Zone: What Is the State of the Digital I/O Channels of My Device When My Computer Powers On? Attachments:
Report Date: 10/21/2004 Last Updated: 07/20/2007 Document ID: 3EKEOKPH |
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