controlling fpga digital output node from realtime boolean

[tman2013]

I have a system where I want to turn on / off a digital output running on the FPGA.    

Once I set the boolean on my realtime side (which turns on the FPGA output), I see the output turn on the CRIO, but it flickers on and off.   (not latching?).   I just want the FPGA to stay on as long as the output is turned on, on the realtime side.  I cant change the mechanical action of the switch due to limitations on FPGA / RT according to labview ( I get an error at compile)

Any suggestions on how to correct this?

 

 

[nathand]

Need more information! In the RT image, where does the "OverWork Warning LL D0" value come from? Is that an image of a subVI that gets called repeatedly, or it's a control that the user clicks, or something else? If it's a control that the user clicks, what is the mechanical action? Do you write to that same digital output from anywhere else in the FPGA code? If you attach your code instead of small pieces of images, it will be easier to help. I would check that the RT-side boolean control always stays true, because it seems likely to me that the problem is that its value is changing repeatedly and the FPGA is responding to that.

[tman2013]

I have simplified my program to something very basic to replicate the problem. 

The digital output D0 switches on and off everytime the realtime loop cycles through. 

If I run just the FPGA seperate and turn on the digital output control D0 it stays on solid. (until I turn it off again)

What am I doing wrong?

[tman2013]

[nathand · Accepted solution]

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@tman2013 wrote:

What am I doing wrong?

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You are resetting the FPGA inside the loop, in "Open FPGA Part.vi". You should open the FPGA Reference once, outside the loop, instead of opening it repeatedly. Each time you reset the FPGA VI the outputs revert to default values.