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Questions on ADSP-21489


I am trying to port some speech processing algorithms on  ADSP-21489, have below questions. Using ADSP-21489 EZ-Board for testing purpose.

  1. Does  ADSP-21489 has data cache? when I tried to read/write from external memory, it takes 30 odd cycles whereas the read/write from internal memory takes 1 cycle. Since our algorithm data requirements will not fit within the internal memory, Is there data cache available to improve the external memory access efficiency, from documentation i understand only Instruction cache is available. Please give some insight about this topic.
  2. From documentation I see that there are library functions for FFT, biquad etc in filter.h. But all these functions work on float data type. Since our algorithm is already written with fixed point code, are there any fixed point variants of the above functions?
  3. Observed that there are no instructions to do arithmetic left shift with saturation, Is my understanding correct? OR is there any way to get the saturation enabled with left shift.
  4. Observed that shift operations on multiplier registers MRF/MRB is not supported,  Is my understanding correct? OR is there any way to get the shift operations on  multiplier registers MRF/MRB.
  5. Does FFT accelerators enabled by default and using of such accelerators will have any impact on overall power consumption of the chip.?

Sorry of lot of questions.!!!

Thank you in advance.

  • Hi Vinoda,

    Apologies for the delay in response.

    Regarding your 1st query,
    >> Yes, there is no Data Cache available in ADSP-21489. Can you please enable the compiler optimization in the IDE by selecting "Project > Properties > C/C++ Build > Settings > Tool Settings > Compiler > General > Enable optimization" and check whether the execution time is reducing.

    Regarding your 2nd query,
    >> The SHARC processor family dominates the floating-point DSP. Hence in filter.h functions are available for floating point.

    Regarding your 3rd and 4th query,
    >> Can you please refer ADSP-2148x Programming reference manual. The link is given below.

    Regarding your 5th query,
    >> It seems that the FFT accelerators are not enabled by default. In order to select the FFT accelerator, please configure the ACCSEL bits in the PMCTL1 register. Please refer the PMCTL1 register(Page No: 959 / 1304) in the ADSP-2148x HRM manual for more information. In accelerators high performance applications, with their ever increasing complexity (such as room equalization or surround sound), even more processing power is needed. Thus, in order to use these accelerators effectively, special care must be taken while designing the application framework.

    Anand Selvaraj.