How to configure VM3011 microphone on the nrf5340_audio_DK

[kaylenptrs]

Hi, 

I am trying to figure out how to change the automatic gain settings on the on-board microphone. It is connected via its I2C to the hardware codec, but apparently not to the nrf5340 SoC. How can I access the hardware codec I2C bus to program the registers on the VM3011 microphone?

[Maria Gilje]

Hello,

I am just letting you know that I am assigned to this ticket and I will handle it as soon as I can. It could take a day or two before I get back to you. Thank you for your patience.

Best regards,

Maria

[multiplex]

Any update?

[Maria Gilje]

Hello,

Sorry about the delay here.

The microphones is configured in the hw_codec driver by populating the pdm_mic_enable_configure array with suitable elements and passing the array to cs47l63_comm_reg_conf_write in hw_codec_default_conf_enable when the gateway or headset device is running a configuration of the nRF5340 Audio application which uses the microphone. The links in the previous sentence is to the relevant lines in the application source code in the following files: nrf5340_audio/src/drivers/cs47l63_reg_conf.h and nrf5340_audio/src/modules/hw_codec.c.

You can change the gain by changing the values for CS47L63_IN1L_CONTROL2 and CS47L63_IN1R_CONTROL2 to other valid values. See the relevant excerpt from Table 4-5 from the CS47L63 datasheet here:

Best regards,

Maria

[multiplex]

Dear Maria,
The gain setting you refer to are post-microphone gains applied inside the HW codec. This is not the issue. The problem we have is with the automatic gain control loop in the VM3011 - which we would like to disable. Can you help by describing the best way to access its registers over the hw codec I2C bus?

KR,
M.

[multiplex]

The mode is described on p7 and the registers on p12 of https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/805/VM3011_DS.pdf