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Original question:

AWR2944: Chirp (idleTime + rampEndTime of profileCfg) time for 1DFFT processing with 256, 512, and 1024 ADC points

AWR2944: AWR2944 range FFT and SDK 4.3

Henry Lin
Prodigy 210 points
Part Number: AWR2944

Hi experts,

  Our company is using AWR2944 to develop some automotive applications, there are some questions need to be clarified,

1.If the range sample (only real part before FFT) is 256、512、1024 points, what are the suggestions of time interval between chirps ?

2.In sdk_04_03_00_01 release note has mentioned some optimizations of DDMA processing chain,is it possible to save more time using sdk_04_03_00_01 compared to sdk_04_02_00_03i n DDMA process chain?

Thanks for reply.

Henry Lin

  • +1
    TI__Mastermind 20605 points

    Hi Lin,

    1) Assuming you are planning to use HWA for your chain, the time interval between chirps needs to be adjusted based on how long your rangeProcDDMA takes per chirp (As preprocessing + 1D FFT + compression is done chirp wise and then copied to L3)

    Initial latency takes around less than 100 cycles depending on preprocessing blocks available (worst case), FFT Cycles = roughly [N + (N * BCNT)] cycles (where N = FFT Size). [FFT block]

    Compression block takes about ACNT+ (ACNT* N) number of cycles.

    You can also add around 100 cycles for EDMA trigger latencies.

    Total number of cycles/ Clock speed of HWA (300 MHz) should give you chirp processing time. So, make sure your chirps have sufficient time according to this thumb rule.

    2) Yes. The 4.3 SDK has performance optimizations with respect to the timings.

    Regards,

    Kaushik

  • 0 in reply to Kaushik Gowda
    Prodigy 210 points

    Hi Kaushik:

      What does the ACNT and BCNT correspond to ?

    For question (2), Can your provide more details of the optimizations before 1D-FFT ? What change in SDK4.3 to improve the timing ?

    Thanks for reply.

    Henry Lin

  • +1 in reply to Henry Lin
    TI__Mastermind 20605 points

    Hi Lin,

    In the FFT paramset, ACNT corresponds to the size of the FFT. BCNT corresponds to the number of Rx antennas.

    In the compression paramset, ACNT corresponds to the number of samples per block and BCNT corresponds of the number of blocks.

    You can look for the same in the following file :mmwave_mcuplus_sdk_04_03_00_01\ti\datapath\dpu\rangeprocDDMA\src\rangeprochwaDDMA.c

    Here is a list of optimizations done on the DDMA chain. (Same is available on doxygen as well)


    Regards,

    Kaushik