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Anyone familiar with Audio codecs, specifically the audio codec( WM8994 ) on the STM32F7 discovery board?

Question asked by 123abc.abc123 on Jul 19, 2015
Latest reply on Feb 19, 2016 by jaekel.torsten
Hi All! I am having a hard time making the communication between the audio codec and the microprocessor to work.

I was able to configure the audio codec to output the audio picked up by two digital mics directly to the headphone jack through the digital sidetone path. Now, I would like to send the mic data to the micro controller to do some signal processing.

 However, I don't really know how the audio codec outputs the raw digital mic data through AIF1 interface so that I can properly configure the SIA2 to receive it. I know the data coming from the digital mics is in PDM format. 

Here is how I have configured the audio codec

AIF1 is set to operate as a slave.
Audio Protocol ----> I2S Standard
Sampling Rate ----> 48kHz
Data Size -----> 16 bits
Disabled Timeslot 0 and enabled Timeslot 1 to receive the mic data.

On the Microcontroller side, I have configured he SAI2 as follows

SAI2_BlockA -- Master TX
SAI2_BlockB -- Slave RX ( Synchronus with BlockA)
MCLK -- ~13 Mhz
BCLK --  ~3 Mhz
Total Slots -- 4
Frame Length -- 64
Data Size(bits) -- 16 

Please let me know if more details are required. Thanks