STM32F4 Series a Question About I2S

[mdmrl00]

Hi, I am trying to do an application where I am using 2 PDM output digital MEMS microphones to get a stereo sound from them and then play it. My question is when I select I2S as Full-Duplex Master for STM32F407VG it only has 1 SD pin. Should connect both microphone's SD pins on this pin or what? Can anyone help me about how to connect two microphones to a single I2S peripheral?

[Peter BENSCH]

MEMS microphones typically have a pin (called e.g. LR or SEL) whose level L or H defines which channel the respective microphone should be connected to. The I2S data stream also contains a selection bit that controls the switching.

Hope that answers your question?

Regards
/Peter

[mdmrl00]

Thank you for the answer. But what I really meant was if I pull L/R pin of one microphone to VDD and the other to GND can I connect them to the same I2S peripheral's SD pin?

[Peter BENSCH]

Yes, it is exactly the purpose of that pin, to connect two such microphones to one I2S.