1 Reply Latest reply on Jan 30, 2017 2:02 AM by nisa

    USB Audio for LInux platform.

    raghavendra.p_1971991

      Hi,

         

      I tried the USB audio example to work under Linux for 16kHZ sampling referring some other post in this forum.

         

      I changed the descriptors and CY_FX3_ISO_XFER_LEN in the code for 16kHZ sampling and it started streaming the audio from SPI flash. But the audio is breaking and looks like elongated (may be because of multiple copies of same audio samples).

         

      Do you have a working example for Linux platform for 16kHZ?

        • 1. Re: USB Audio for LInux platform.
          nisa

          The sound depends on the sampling rate. If the sampling rate is changed, then you will get some difference in the sound using the same audio file as well. The CY_FX3_ISO_XFER_LEN  depends on the sampling and the data you want to transmit. You can check the follow to understand the relation: 

             

          1) Use one Audio file, write it to SPI flash. 2) Use the default firmware with length 96, and sampling at 48KHz. 3) Use firmware with length 32, and sampling at 16KHz. 4) Use firmware with length 96, and sampling at 16KHz (It shouldn't work as expected). Now, instead on decreasing the sampling rate, you can perform a similar experiment by increasing the sampling rate, 

             

          The transfer length depends (CY_FX3_ISO_XFER_LEN  )  is used to indicate the size of the DMA buffer, so it is necessary that it should be set as per the requirement