13 Replies Latest reply on Mar 18, 2020 10:31 PM by AnjanaM_61

    CYW20706 and SPH0645LM4H MEMS microphone

    WeJi_4584096

      Hello,

       

      I am trying to build a Bluetooth headset with the CYW20706. I am new to PSoCs but I have been able to get the transducer output working via a DAC/AMP combo. However, we have been unable to get the our MEMS microphone to work consistently: https://media.digikey.com/pdf/Data%20Sheets/Knowles%20Acoustics%20PDFs/SPH0645LM4H-B.pdf

       

      I found out that the I2S clock is only ~512kHz whereas the mic requires 1.024 MHz to go into active mode (even though the spec sheet says it runs at 1.5 MHz or 2.4 MHz?) I found out another potential issue is that the CYW20706 only takes 16 bits while the microphone outputs 24 bits, however we should be getting some kind of noise at all times? The microphone does not output anything even when its output pin is not connected to the eval board's I2S input pin. However, sometimes we are able to get audio SOMETIMES by first physically floating the LRC and SEL pins on the mic, which creates some noise, then plugging both into VCC. Occasionally after the noise appears it is able to pick up human audio. We are stumped as to what the issue is as we cannot repeat this phenomenon. We are using HFP. Any guidance would be greatly appreciated.