SPH0645 I2S MIC DATA FORMAT

[Kashyap23]

Hi,I have been using nrf5340 audio DK Board to access the I2S .I am using SPH0645 mic with that i need to get mic data .My Mic datasheet specifies that "The Data Format is I2S, 24-bit, 2’s compliment, MSB first. The data precision is 18 bits; unused bits are zeros".Do I need to convert the value ? As it specifies data of 2's complement value in order to get original mic data or it will be internally converted by the nrf5340 controller itself.I am taking data size of 32 bit and in that I am taking 16 bit of each mic data and confirm me regarding data format whether to be Left-justified or Right-justified.I am attaching the Datasheet of I2s mic.

Regards,

Kashyap

[Elfving]

Hello Kashyap,

I see that the last case you've opened was a bit similar to this one, and it was recently answered as well. I assume this is somewhat of a duplicate then.

Regards,

Elfving

[Kashyap23]

That's related to a different thing but here it's regarding the data format .I want to know how data is available using nrf5340.Can we use data directly?or we need to conert back from 2's complement.

[Elfving]

Understood.

The Data Format is I2S, 24-bit, 2’s compliment, MSB first. The data precision is 18 bits; unused bits are zeros".

The data looks fine. The i2s should support all of that, and 24-bits. If you want to use LE Audio however, I believe that the LC3 codec only uses 16 bits at the moment, but that is not a real problem.

For more on i2s on the 5340, see here.

Regards,

Elfving

[Kashyap23]

Kashyap23 said:

data of 2's complement value in order to get original mic data or it will be internally converted by the nrf5340 controller

Ok,thank's for that .I have doubt regard data ,I am trying to print data and convert to wav file,in this case do i need any conversion of 2's complement value to get original audio or this wont be necessary thing.Can I use directly what I get without converting 2's complement value?

[Elfving]

Kashyap23 said:

Can I use directly what I get without converting 2's complement value?

That should be fine, 2's complement is normal. 

Regards,

Elfving