STM32F7 Discovery: need help in getting SAI/I2S to work to receive microphone data

[sjpatel1992]

Posted on August 23, 2015 at 01:24

Hello Everyone.

As the title suggest, I am trying to receive data from the two digital microphones that are on the STM32F7 discovery board. Since the microphones are connected to the audio codec, I need to interface with the code to receive the data. I am using DMA to automatically transfer the data from SAI to memory.

I have looked at the examples provided and have managed to get it to work partially.The problem is with the data received.

Here is a pic of the data I am getting when there is little to no sound

http://pasteboard.co/4uu899x.png

As you can see, it fluctuates between either really high or really low values.

Please see the attached file for code.

#stm32f7 #sai-audio-codec

[thomfischer]

Posted on August 23, 2015 at 13:24

it's two's complement data, so all are really low values.

change your data watch window to signed.

[sjpatel1992]

Posted on August 23, 2015 at 16:26

Thank you so much. 

[samuelpeterdelaney]

Posted on September 23, 2015 at 23:03

Have you managed to retrieve data from both microphones at once?

The codec for the audio processor looks like it only supports one microphone or line in.