um hi,
i have actually switched updated my xilinx sofware ISE 11 to get Virtex6 support.
in that i have used the FFT v7.0. i have made a few corrections and both FFT ant IFFT have started working
1. i was using the run time configurable transform length.
-the nfft_we should be high for only one clock cycle during which the transform length Nfft is being configured. if Nfft_we is tied to high, it keeps on trying to configure the block and hence the processing never starts.
-the input data to the FFT block has to be sent with one clock delay after the dynamic transform length is set.
2. though, the dynamic transform length is being used, the transform length that can be chosen in block parameters from the drop down list has to be set at the maximum that u may be using. the dynamic length can be for setting any size smaller than the transform length in the block parameters only.
with these 2 modifications, the FFT started to work.
3. for the IFFT, i have noticed that the output of FFT seems to saturate the IFFT and hence was not giving me results. so i did the 1/N scaling after the FFT and havethen passed the data to IFFT. due to this scaling, the IFFT also started working
Aarunya
