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FFT accelerator question

Question asked by ClaireCanada on Mar 26, 2012
Latest reply on Dec 8, 2013 by dougcl



I am doing a class project for my supervisor Dr. Smith to show the use of SHARC FFT accelerators. I have down loaded the plug-in to generate the PLL init files and the FFT init files


Two questions

Init_PLL_ddr_ami file contains the include file call





where do I get cs_macros.h -- I am using Visual DSP version and that does not pick up the include file from the system includes


When you use the FFT code generation tool, there is a global setting for all channels  -- data format floating


However when I set the format to floating -- the code generated is for   extern int buffers and not extern float buffers


How can I ensure that the FFT is being performed in floats?


Going back to the 21469 example code 256fft

I would have expected that the output file would be complex -- is it stored as an array of real and then array of imaginary

or real and imaginary alternately -- I have used plot to try and recognize the format -- (stride 1 or 2) but the results plotted don't seem to make sense -- I am obviously not getting magnitude as there are positive and negative values.


It would really make my day

if you could direct me to an FFT example -- completely working in C rather than assembly code