PFI or static I/O selection on USB modules

[V.Life]

Hello.

I need to use a USB module in my Labview project to receive 3 static digital signals and a pulse train.

I read that USB-6210 has: 

Number of digital input channels

4 (PFI <0..3>/P0.<0..3>)

Is it possible to use 3 of these channels as static digital inputs and the other one as PFI with a counter to detect the frequency of the pulse train? Or are necessary more than 1 PFI pins?

It's the first time that I have to use this kind of modules and I hope to buy one that can do what I need in my project.

Thank you

[Kevin_Price · Accepted solution]

Counter tasks and other timing signals (like clocks and triggers) *need* to use PFI lines.  Only the terminals with a PFI designation can be routed into the timing-sensitive parts of the DAQ circuitry.

DO and DI generally do not need to use PFI lines, though on many devices at least some of the Digital I/O terminals are "shared use" and can also be used as PFI lines.

It appears that your device has limited DIO and all of it is shared with PFI functionality.  You show 4 dedicated DI lines, I suspect you have 4 dedicated DO that'll be designated by one of PFI<4..7> OR P0.<4..7>

You should be fine to use P0.0, P0.1, P0.2 for DI while using PFI3 for your counter frequency measurement.

-Kevin P

[V.Life]

Thank you Kevin.

The pin for the frequency measurement has to be exactly only PFI3 for a specific reason? Or I can choose a different one?

[Kevin_Price]

You could choose any one of PFI 0-3 for frequency measurement.  Probably any one of PFI 4-7 as well, but since those double as DO terminals, you could run into issues down the road if you need to do DO.

I only specified PFI3 as a convenient example.  It only needs to be different than the terminals used for DI.

-Kevin P