FPGA IRQ Acknowledment not recieved...?

[demoman]

Hello guys

I have a strange issue with IRQ exchange between FPGA VI and RT Host VI. The platform is NI cRIO-9082RT, the code is done in LabView 2013 SP1, FPGA Module 2013 SP1 and RT Module 2013 SP1:

1. The FPGA VI sends an IRQ ("Shutdown mode") and waits for it's acknowledment from the host RT VI.

2. The RT VI recieves the IRQ, executes some code and sends an acknowledment back.

3. The problem is that sometimes (80% of cases) the FPGA seems like it's not recieveing the acknowlegment. The code stays stuck in the IRQ sending frame from the 1st screenshot - the User1 LED stays yellow and the dbg DMA indicator stays at -1.
I've tried forcing the ACK IRQ node on the RT to execute several times (even endlessly), but there was no effect.

What can be the reason of FPGA not recieving the acknowlegment? Anything else I can check/do to fix this? Or at least eliminate some possibilities?

If you need more info on the case let me know.

Thanks in advance for the support!

Alex

[KHartley]

Hey Demoman,

What happens if an error propagates through your RT section? Try adding some error logging to the section of code and see if anything trickles up. I would try watching for an error as typically this will cause our code to not execute. If you are not passing the error back around with a shift register I could see how you may be loosing this between executions.