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TMS320F280049: VCU example

Strong ZHANG
Expert 4400 points
Part Number: TMS320F280049
Other Parts Discussed in Thread: C2000WARE

Hi Team,

My customer want to use F280049 VUC for CFFT,  do we have an example based on F280049 for that?

As it seems there is no VUC example for F280049, They migrate the code from the 2837x_vcu2_cfft_256 example, but has the issue below:

C:\ti\c2000\C2000Ware_2_00_00_02\libraries\dsp\VCU\c28\docs\C28X_VCU_LIB_UG.pdf

 C:\ti\c2000\C2000Ware_2_00_00_02\libraries\dsp\VCU\c28\examples\fft\2837x_vcu2_cfft_256

The code are below:

CMD file to fix the data buffer address:

The input buffer from debug window:

The output buffer after calculation from debug window:

but the output result should be like below:

what is the problem? is it because F280049 VCU is type 1 and F2837x VCU is type 2 and not able to use this example? any suggestion or example  for F280049 VCU to implement CFFT?

  • 0
    TI__Mastermind 25930 points

    Hi Strong,

    Please give me a day to look into the details of this issue and get back to you. I don't believe VCU Type should make a difference here. FFT should work properly on both.

    Thanks,

    Sira

  • 0 in reply to Sira Rao80
    TI__Mastermind 25930 points

    Strong,

    We don't have a 28004x VCU FFT example. 

    However, we do have a 2837x VCU0 CFFT 256 example that would be a better starting point for migration to 28004x.

    C2000Ware_3_01_00_00\libraries\dsp\VCU\c28\examples\fft\2837x_vcu0_cfft_256

    Could you please try this (latest C2000Ware version as well). It also has a Pass/Fail condition (like the other examples) so you will know the test result.

    Let me know what you find.

    Thanks,

    Sira

  • 0 in reply to Sira Rao80
    TI__Expert 4400 points

    Hi Sira,

    If use FPU to implement FFT for 256 point, the performance data is 6149.

    If use VCU0 to implement FFT for 256 point, the performance data is 8135.

    If use VCU2 to implement FFT for 256 point, the performance data is 2908.

    The performance that compare FPU, VCU0, VCU2 is that VCU2> FPU > VCU0.

    question is could customer migrate VCU2 example from F2837x to F28004x to implement the FFT?

    If VUC2 example is not able to support F28004x, which module do we suggest customer to use? FPU or VCU0?

  • 0 in reply to Strong ZHANG
    TI__Mastermind 25930 points

    Hi Strong,

    Interesting comparison - you taught me something new.

    I know that the VCU2 implements instructions that make it more efficient than the VCU0 in implementing the FFT. So it is a Hardware benefit. 

    Unless I am misunderstanding what you are saying, using the VCU2 CFFT 256 example to migrate to 28004x is not going to give you any benefits.

    It looks like the FPU is the clear choice here over VCU0.

    Thanks,

    Sira