TDA3XEVM: Output Buffer for 1FFT

Khai Trinh

Part Number: TDA3XEVM

Hi,

If the FFT Control Parameter is set to do both Horizontal and Vertical, how do I gain access to the 1FFT output buffer? I looked at the radarFft2.c code and saw intermediateBuf. Is this the 1FFT output buffer? I would like to get a hold of the 1FFT buffer and perform a power level check on the data on a per frame basis.

Thanks,

--Khai

over 6 years ago

0 Piyali Goswami over 6 years ago

TI__Mastermind 30245 points

Hi Khai,

Yes the intermediate buffer is the 1D FFT output.

You can add some logic in the Radar FFT code to calculate the power of intermediate in the EVE code or DSP code (workQ master).

The other option is you have 2 links for FFT, one does horizontal and other does vertical. and in between these two links you add a new link where you are looking at power level.

Thanks and Regards,

Piyali

0 Khai Trinh over 6 years ago in reply to Piyali Goswami

Genius 4140 points

Hi Piyali,

Thanks for the response. If I am using a 2D FFT link and access the intermediate buffer from DSP, will this buffer be available after EVE performs 1 and 2 FFT? Wil this buffer ever be disappeared?

Regards,

--Khai

0 Piyali Goswami over 6 years ago in reply to Khai Trinh

TI__Mastermind 30245 points

Khai,

If you are doing the 1D and 2D FFT operations in the same link, the Link allocates a buffer in the cached DDR location. This location does not change across frames, although the content may change from 1 frame to the next.

If you plan to add logic in the AlgorithmFxn_RadarFftProcess running on the DSP, after the EVE has finished processing the 1D and 2D FFT, you can access the intermediateBuf which contains the 1D FFT output to perform the power level check.

Thanks and Regards,
Piyali

0 Khai Trinh over 6 years ago in reply to Piyali Goswami

Genius 4140 points

Hi Piyali,

I need to find out the target peak energy in one of the range 1FFT buffer in intermediateBuf on a per frame basis. Is there an optimized DSP function call to perform this calculation?

Thanks,

--Khai

0 Piyali Goswami over 6 years ago in reply to Khai Trinh

TI__Mastermind 30245 points

Khai,

You can take mmwavelib_log2Abs16 function as reference (C:\PROCESSOR_SDK_VISION_03_06_00_00\ti_components\algorithms\mmwave_sdk_01_02_00_05\packages\ti\alg\mmwavelib\src\detection\mmwavelib_log2abs.c) . You would need to take care to add the logic to parse the 1D FFT output from DDR and send it to this function.

Thanks and Regards,
Piyali

0 Khai Trinh over 6 years ago in reply to Piyali Goswami

Genius 4140 points

Hi Piyali,

Why are you suggesting to use the mmwavelib_log2Abs16() but not the mmwavelib_log2Abs32()? Does fst FFT output 8bit I and 8bit Q while 2nd FFT I know it's a 16bit I and 16bit Q.output.

Thanks,

--Khai

0 Khai Trinh over 6 years ago in reply to Khai Trinh

Genius 4140 points

Never mind. i need mmwavelib_log2Abs16(). Thanks

0 Khai Trinh over 6 years ago in reply to Khai Trinh

Genius 4140 points

What's the format of the 1FFT buffer in intermediateBuf look like? it's an UInt8*. But I suppose it's 16bit I, 16bit Q?

0 Piyali Goswami over 6 years ago in reply to Khai Trinh

TI__Mastermind 30245 points

It is 16 bit I and 16 bit Q data.

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TDA3XEVM: Output Buffer for 1FFT