Hi Pereira,
The FFT accelerator examples are available in the VisualDSP++ installation folder itself (Analog Devices\VisualDSP 5.1\214xx\Examples\ADSP-21489 EZ-Board). You can find two example projects which performs 256 point FFT and 512 point FFT. For the quick reference I am attaching the same files here as well.
Regards,
Jithul