No output on FPGA

OregonGumby · ‎07-05-2017

I am an experienced LabVIEW programmer but new to FPGA. I have developed a small program for simulating quadrature encoder signals. I ran it on the desktop emulator and everything runs perfect. Now I'm trying to run it on the target and I'm getting no output. I compiled it to run when loaded and it compiled with no issues. I checked wiring and didn't find any issues, so I'm hoping someone here can point me in the right direction.

The target is a PXI-7841R. In the attached project, there are several simulation programs. I'm starting with the simplest one - Quadrature Channel.vi

nanocyte · ‎07-05-2017

Think about trying to display what you're outputting to Quadrature outputs. If you were running Quadrature Channel as top level you could just wire up indicators. Even though the signal is really fast you should still see blinking. If those are blinking, the next thing you want to is to probe the physical interface and see if you see the right signal with the right phase.

Also, I notice you are closing your FPGA references right away. It's possible that's stopping the FPGA. Remove the close to see if that fixes it.

OregonGumby · ‎07-05-2017

I verified the logic with the desktop emulator which put out a graph of the outputs. Now I compiled it and ran it on the fpga target and I'm looking at the output on a scope and I see nothing.

nanocyte · ‎07-05-2017

What about the indicator LEDs I suggested? Are those blinking?

OregonGumby · ‎07-06-2017

It works now. I did as you suggested and wired some indicator outputs on the PC side application and put it in a loop. Once the PC application was running, the FPGA output appeared. I didn't realize that the PC side application was required. Thanks!

nanocyte · ‎07-06-2017

It's not entirely required. You just have to make sure not to abort the FPGA application from the PC side. See the options at the end of this article.