Get DIO to trigger waveform generation

[Stefan019]

Hi,

I am trying to get a digital IO line to trigger waveform generation. I have a function call that invokes WFM_Op(), which is set up to trigger on one of the PFI inputs. This part works fine for an externally generated interrupt.

What I want to do is use one of my digital output lines, looped back to the PFI input, as the signal source. However when the call is made to the DIG_Out_Line() it hangs, it seems like it's waiting on the call to WFM_Op() to finish first. (Obviously my program is multithreaded)

It seems pretty weird that you wouldn't be able to do this, the two things should be separate.

Anyway if you have any suggestions or another method to attempt that's more to your liking please let me know.


Stefan
Tarrant
Research Engineer
C-CORE
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[L Aguila]

Stefan,

I have one suggestions for you. I hope it works out for you:

Create two programs: one for waveform generation and the other one for outputting the digital signal out of one of the the DIO lines, or a second program which generates a pulse train, out of a counter.

I don't understand exactly how you are allocating the function calls.Are you placing the function calls one after the other; that is, first a WF generation one,and then a DIO function. Or, two separate sets of functions on different threads? If it is the first one, you will not be able to accomplish what you want.

If this doesn't help, let me know. If you can attach a simple code that depicts the problem, it would be great.

Hope this information is helpful.

L Aguila
Appl
ications Engineer
National Instruments

[Stefan019]

I tried that and run into the same problem, all digital output lines seem to be "locked" at the hardware (or driver) level while a WFM_Op() operation is in progress.

It looks like we have to use an external trigger.