How to set additional PDM microphone in nRF5340 audio sample

[LandyWang]

Hello,

As the title, I'm using nRF5340 audio sample to test Walkie Talkie demo.

I know that in nRF5340 audio DK, the microphone is set through CS47L63. Now I want to use the nRF5340 module (custom board) to test the Walkie Talkie demo. I replaced the CS47L63 mic with an additional PDM mic.

I referred to the dmic sample, which seems to just set up a digital microphone and collect a piece of audio from the microphone, and doesn't do anything else with the audio.

It seems that if I want to use an additional PDM microphone to test the Walkie Talkie demo, I need to complete the subsequent audio transmission process by myself. Is this inference correct? Or is there another way to configure an additional PDM microphone?

[Sigurd]

Hi,

It seems that if I want to use an additional PDM microphone to test the Walkie Talkie demo, I need to complete the subsequent audio transmission process by myself. Is this inference correct?

I believe this is correct, but I will check with our Audio team.

[LandyWang]

Hello,

I looked a bit more into the code.

On the hardware, CS47L63 is connected with a digital microphone. After sending the command in the code, CS47L63 transmits the Mic in data to I2S Tx.

Therefore, the Walkie Talkie demo is actually dealing with I2S in audio, but the input source is Mic in data converted by CS47L63.

To implement the Walkie Talkie demo without using CS47L63, I need to complete the process of sending Mic in data to I2S Tx by myself. This is my current speculation.

If this assumption is true, I would like to ask whether there will be a new version of audio sample that supports external digital mic, and does not need to complete the process of sending Mic in data to I2S Tx by myself?

[Sigurd]

Hi,

I checked with the Audio team, and your assumptions are correct. We don't support PDM MIC at this moment in the audio application, and you currently need to implement this by yourself.

[LandyWang]

Ok, I see. Thank you for your assistance.

[Anushikha]

Hello 
Were you able to interface with the external PDM mic?
Since the Dmic sample has many limitations with nrf5340 audio DK I am also thinking of using the external PDM mic. It would be very helpful if you guide me on this, where to start.