FFT Array Length

Brandon Contino

Other Parts Discussed in Thread: CONTROLSUITE

Hi,

Does anyone know how many point real FFT's the VCU can compute today? I found documentation of the VCU in the controlsuite folder, ti\controlSUITE\libs\dsp\VCU\v110\doc, saying that: "The library supports 64,128 and 256 point Complex FFTs,128, 256 and 512 point Real FFTs and 64, 128 and 256 point Inverse FFTs. They share a common data structure"

Is the VCU still limited to only 512 points for a real FFT?

Thanks,

Brandon

over 9 years ago

0 Vishal_Coelho over 9 years ago

TI__Mastermind 20850 points

Hi Brandon,

There is a newer version of the VCU library in controlSUITE, v2.00. If the device you are using supports VCU type 2 then you should be able to do a 2048 point RFFT, however, vcu type 0 devices only have code for a 512 pt RFFT max

0 Brandon Contino over 9 years ago in reply to Vishal_Coelho

Prodigy 165 points

Hi Vishal,

Thanks for your quick response! Luckily I have a F28377D so it has VCU-II. Do you by chance know where/if the example code for a 2048 rfft is located? I currently checked ti\controlSUITE\libs\dsp\VCU\v2_00_00_00\examples_ccsv5\fft and couldn't see it. Also, do you know what the max rifft is?

Thanks,

Brandon

0 Vishal_Coelho over 9 years ago in reply to Brandon Contino

TI__Mastermind 20850 points

I didnt write an example for the 2048 rfft but you can modify the 512 example by altering the following lines:

36: #define NSTAGES 10

142: CFFT.init = (void (*)(void *))CFFT_init1024Pt;

143: CFFT.run = (void (*)(void *))CFFT_run1024Pt;

and max rifft should also be 2048 points. Again, you will have to modify the 128 pt example to use the 1024-pt functions instead of the 128-pt functions.

0 Brandon Contino over 9 years ago in reply to Vishal_Coelho

Prodigy 165 points

Thanks Vishal!

-Brandon

C2000™︎ microcontrollers

C2000 microcontrollers forum

FFT Array Length