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IMX6ULL + WM8960. Microphone isn't working.

Question asked by Almaz Khamidullin on Jun 3, 2020
Latest reply on Jun 3, 2020 by igorpadykov

Hello.

Trying to get microphone and audio working using WM8960 codec based on ReSpeaker_2_Mics_Pi_HAT dev board with custom IMX6ULL board.

Here is schematic of ReSpeaker_2_Mics_Pi_HAT dev :

So there are WM8960 with Headphone jack and two microphones SA0-3729.

As MCLK pin of WM8960 clocked from separate 24MHz quartz and DACLRC shorted with ADCLRC the following wiring with IMX6ULL implemented:

|-----------------------|-------------------------------------|-------------------------------|

| IMX6ULL GPIO  |     IMX6ULL GPIO FUNC   |   WM8960 GPIO          |

|-----------------------|-------------------------------------|-------------------------------|

| SD1_DATA0       -     SAI2_TX_SYNC            -       DACLRC               |
SD1_DATA3       -     SAI2_TX                        -       DACDAT               |
SD1_DATA1       -     SAI2_TX_BCLK            -       BCLK                     |
SD1_CMD          -     SAI2_RX_SYNC           -                                     |
SD1_DATA2       -     SAI2_RX_DATA            -      ADCDAT                 |
SD1_CLK           -     SAI2_MCLK                  -                                     |

---------------------------------------------------------------------------------------------

E.g. SAI2_RX_SYNC and SAI2_MCLK pins of IMX6ULL left unconnected.

 

While all looking to IMX6ULL EVK schematic I see that all six WM8960's pins: DACLRC, DACDAT, ADCLRC, ADCDAT, BCLK and MCLK connected to relative IMX6ULL's pins.

 

So, I hear sounds using headset connected to jack when I play some audiofile:

 

$ aplay sample.wav

 

But no luck with recording:

$ arecord -f S24_LE -r 48000 -Dhw:0 test.wav

$ aplay -Dhw:0 -r 48000 test.wav

Just noise instead of sounds.

So I am wondering if unconnected SAI2_MCLK and SAI2_RX_SYNC can be an issue of non working microphone or something else? 

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