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IWR6843ISK: FFT calculation ability problem

Annie Liu
Genius 10295 points
Part Number: IWR6843ISK

Hi Team,

The customer currently loads the corresponding program in the out of box demo, he sees that in the document in mmwave_sdk_03_04_00_03:

1. Use HWA to achieve the distance dimension: adc samples/range bins:64-1024 (3Tx, 4RX, 1024 not supported)

2. Use DSP in the distance dimension: adc samples/range bins: 64-2048

3. The speed dimension is implemented using HWA: numdopplerchirps/numdopplerbins: 4 x numRxAntennas x numTxAntennas x numDopplerChirps <= 16384 (if using 3tx, 4RX, calculate numDopperChirps as 384)

4. The speed dimension is implemented using DSP: numDopplerChirps:Must be a multiple of 4.

numDopplerBins:Must be at least 16. Must be power of two greater or equal than numDopplerChirps

Customer would like to know: (3 sending and 4 receiving are used)

1. If HWA is used for the distance dimension and 512 points are used for the distance dimension, can the speed be achieved in the HWA dimension with points <384? Speed dimension is implemented in DSP, is it more than 16? Is there an upper limit?

2. If the distance dimension uses DSP and the distance dimension uses 2048 points, can the speed be achieved in the HWA dimension with points <384? Speed dimension is implemented in DSP, is it more than 16? Is there an upper limit?

Thanks,

Annie

  • 0
    TI__Mastermind 23725 points

    Hello

    We might need some clarification on what is expected here. 

    Most of the questions seem like of nature  if this  -- then what? 

    Our simplest answer would be to try it and see. In order to get specific answers I am going to rephrase the questions below:

    Please confirm if this is what you mean to ask:

    1. If HWA is used for the distance dimension and 512 points are used for the distance dimension, can the speed be achieved in the HWA dimension with points <384? Speed dimension is implemented in DSP, is it more than 16? Is there an upper limit?

    HWA will be used to do distance computation using 512 FFT (1D fft)

    HWA will be used to do velocity computation 384 pt FFT (2D fft)

    Limit is based on memory : Please make sure you have enough memory available for computation.  Have you seen any issues while performing the above computation?

    2. If the distance dimension uses DSP and the distance dimension uses 2048 points, can the speed be achieved in the HWA dimension with points <384? Speed dimension is implemented in DSP, is it more than 16? Is there an upper limit?

    Yes the cores of the devices are completely programmable by the user.  So one can move the data and run through required

    We do not understand what the yello highlighted question means.

    Please help us with clarification.

    Thank you,

    Vaibhav

  • 0 in reply to Vaibhav Mahimkar
    TI__Genius 10295 points

    Hi Vaibhav,

    Thanks for your support.

    Customer currently used IWR6843ISK, (3 tx, 4 rx). The memory used to store radar data is 512k.

    He set the distance dimension to 64 and the velocity dimension to 128. He calculated 64*128*3*4*4=393k,It could be configured in mmWave_Demo_Visualizer 3.4.0 and run out various radar graphics.

    When he set the distance dimension to 256 and the velocity dimension to 32, it was also achievable.

    But he changed the distance maintenance to 512 and the speed maintenance to 16, always prompted a configuration error.

    Customer would like to know that 512*16*3*4*4=393k satisfies the memory computing requirements, why can’t it be set to 512?

    Thanks,

    Annie

  • 0 in reply to Annie Liu
    TI__Mastermind 30405 points

    Hi Annie,

    1. From your description, I assume the customer is using the xwr68xx OOB demo which uses both HWA and DSP for point cloud processing (and not the xwr64xx OOB demo which uses only the HWA for all operations)

    2. Please run the demo in CCS debug mode to get the error shown on CCS console. The CCS debug mode procedure is provided in 68xx ISK - mmWave SDK Demo user guide as shown below (section - 4). The error description from CCS console is required to understand the problem (e.g. is it memory or MIPS related).

    Regards

    -Nitin

      

  • 0 in reply to Nitin Sakhuja
    TI__Genius 10295 points

    Hi Nitin,

    Customer confirmed that the problem has been solved according to the error prompt.

    Thanks for your help.

    Annie