TMS320F280049: FFT on VCU

Due to holiday at TI India office, please expect response by tomorrow.

Hi Jordan

1) Do we have "cfft16_512p_calc"? "cfft16_256p_calc" works fine, and 512 points function is needed. It's not founded in VCU user manual.

There is no 512p fft available.

2) Based on F2837x_vcu2_cfft_512, I did the same in F28004x, after running, a lot of failures. Any comment, please?

F28004x has VCU-I and hence the VCU-2 code probably will not run. 

3) What is the difference of CFFT and RFFT? 

CFFT is complex FFT while RFFT is real FFT. complex FFT works on complex signals (real and imaginary parts). 

4) What's the execution time of CFFT on VCU?

can you tell me on which device you want to measure this ? F28004x and for which example (fft length). We can try to generate the data. 

5) In F280049, which library can be used, "c28x_vcu0_library_fpu32.lib" or "c28x_vcu2_library_fpu32.lib"?

please use the c28x_vcu0_library_fpu32.lib and let us know if you see any problems.

Thanks

Aravindhan

Aravindhan,

Now we are going to run CFFT on F280049 VCU, 512 points.

Do you have any suggest?

From your comment, it seems no possible to run 512 points CFFT on VCU. 

Thanks a lot.

Br, Jordan

Jordan,

Can you first try to run  the 256 point cfft of vcu-0 on F280049 and see if you can get that to work ? i think for 512 points we will have to write new code. 

Thanks

Aravindhan

Aravindhan,

256 points of CFFT, VCU-0, it works fine.

We just need 512 points of CFFT. 

it's a little urgent. 

Thanks a lot.

Br, Jordan

Jordan,

i will take a look at the effort and discuss internally and let you know whether we can do this quickly. give me time till mid next week.

thanks

Aravindhan

Thanks Aravindhan.

Br, Jordan

Aravindhan, 

Another doubt, how long does it need for 512 points RFFT on VCU0?

fft.ipcbptr = (int *)RFFT16_512p_in_data + 0;
fft.workptr = (int *)fft_work_buffer + 0;
fft.init(&fft);
rfft16(&fft);

On F28004x Flash execution, they takes about 25000 clocks. Is it correct?

How long does VCU0 need for 512 points RFFT?

Br, Jordan

Jordan,

I need to run on F28004x and see the performance numbers. I will do it next week and send you a note.

Thanks

Aravindhan

Aravindhan,

Any feedback, please?

Thanks a lot.

Br, Jordan

Got it with many thanks. 

Br, Jordan