Sharc Audio Module Latency

I would like to prototype an adaptive noise cancellation algorithm using the Sharc Audio Module.  For this, I cannot work within the latencies offered by the existing Bare Metal Framework, as these are at least 167uS long using a single DSP and the minimum block size of 8.  I am wondering whether there is support for sampling a pair of stereo signals, processing these, and outputting to DACs, all in the same sample time.  If there is not existing support will the ADAU1761 and SC589 support this operation and how difficult would it be to write the code for this configuration?

Thanks

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  • Hi,

    You can reduce the block size to a smaller number but the side effect is more system overhead. In the audio_system_config.h, the preprocessor directives (line 239-245) check is if the audio block size is between 4 and 128. If not, the project build fails. Do you think a block size of 4, or 83 us, fits in with your requirements? 

    Thanks

  • Ideally I would like something on the order of 10uS latency (which would enable cancellation up to 10kHz or so.  83uS would be an improvement over 167uS but would mean I could cancel up to 1500Hz instead of 750Hz which would allow a lot of higher frequency noise through.   If I overrode the block size limit of 4 and allowed it to be 1 that would get me to 20.8uS latency which might be enough and still could work within the bare metal framework.  Any idea how many cycles per sample would be available for processing audio in that configuration?  

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  • Ideally I would like something on the order of 10uS latency (which would enable cancellation up to 10kHz or so.  83uS would be an improvement over 167uS but would mean I could cancel up to 1500Hz instead of 750Hz which would allow a lot of higher frequency noise through.   If I overrode the block size limit of 4 and allowed it to be 1 that would get me to 20.8uS latency which might be enough and still could work within the bare metal framework.  Any idea how many cycles per sample would be available for processing audio in that configuration?  

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