FFT IP Simulation in ModelSIM

[nissan.luzon]

Good Afternoon,

In our project we use Xilinx FFT IP.

The sources are created in VIVADO 2017.2 and the simulation are done with ModelSIM v10.5c which is compatible to this VIVADO's version.

I use the "Compile Simulation Libraries" dialog box, and manage to compile successfully all the libraries, including the xfft_v9_0_12 library (i.e. the library xfft_v9_0_12 is shown in ModelSIM library tab, and it's not empty and contain some encrypted entities within).

So far - everything is OK.

However, when I run the command vsim -t ps -L xfft_v9_0_12 <TestBenchName> in ModelSIM, the tool print a lot of warning messages indicating the IP is not driving any output signals, such as:

** warning: (vsim-8684) No drivers exist on out port /..../UUT/U0/<protected>/<protected>/<protected>, and its initial value is not used.

Is there any reason why this happens??? What can be done to solve it??

[guillaumebres]

my guess these signals are dependent on the settings you set for the IP core, like error monitoring or optional interfaces. If that is the case there's not much you can do about it. Is that critical to your simulation run?

[amaccre]

Hi @nissan.luzon,

If you run the simulation using VIvado simulator or if you launch ModelSIm from within VIvado, are you seeing any difference in results?

If not, can you try the following command to generate the scripts to run the simulation in ModelSim

export_simulation -simulator modelsim -directory ./test

You can then check your scripts against those created by the tools.

Best Regards
Aidan