Question about SAI configuration with a MEMS microphone

[EEnco.1]

I want to connect a MEMS microphone to my stm32 using its SAI interface.

I found a document called "Interfacing PDM digital microphones using STM32 MCUs and MPUs" which gives some examples about how to do it.

My question is about the configuration :

Why is number of slots equal to 4 ? I dont understand what this parameter represents.

In this example, the data size is set to 16 bits and frame length to 64 bits (with free protocol mode).

 

Sorry if this is a newbie question but why are these two parameters set with different sizes ? I would think that data size should be equal to frame length as I'd want to get all the data sent by my digital microphone. Thanks

[Bouraoui Chemli]

Hi,

What is the STM32 are going to use?

Please refer to dedicated section in the reference manual "Serial audio interface (SAI)"

Bouraoui

[Eleon BORLINI · Accepted solution]

Hi @EEnco.1​ , @Bouraoui Chemli​ ,

this post should be solved, see this thread.

-Eleon