Are the pull-downs configurable on the PXIe-7821R lines?
Reason I ask, I currently have an external 10K pull-up on one of the lines and am noticing slightly less than 3V on the line. The external 10K pull-up is connected to an open collector output of an opto-isolator. I assume that either the transistor output of the opto-isolator is slightly on or there is a pull-down on the lines of the PXIe-7821R. Based on the documentation for the card, there appear to be pull-downs on the lines set by default when the card powers on.
Are these pull-down resistors configurable via software? For instance, can I turn the pull-down off? Is there a pull-up I can turn on instead? Is it suggested to use a stronger external pull-up instead?
I'm not clear on the hardware capabilities are for this card.
FYI, the line doesn't have to be at 3.3V, however, I am scratching my head wondering why it's not.
I disconnected the line from the PXIe-7821R and the voltage went back up to 3.3V. So the PXIe-7821R appears to be pulling down the line.
This is not a huge concern however I am wondering if the output topology is configurable on this card and how that might be controlled through software.