STM32F469I-DISCO SAI Peripheral for MEMS microphone.

[AlecCT]

I'm using an STM32F469I-DISCO ($AU1) board that I've used for a few little projects and have come to try to prototype something using it's MEMS digital microphones (MP34DT01-M).

In the documentation for the discovery board it lists the connections of these microphones to the DFSDM peripheral pins of the MCU, however looking in the datasheet of the F469 it doesn't list the DFSDM peripheral anywhere and on pages that discuss the DFSDM peripheral the F469 is not listed as an MCU with DFSDM compatibility. Furthermore, on the CubeMX example project for the F469I-DISCO the pins connected to the MEMS microphones are configured with the SAI peripheral.

Is this a documentation issue for the discovery board or are there extra steps I need to take to use the DFSDM peripheral?

Thanks for any help anyone can provide.

[pedro68]

Thanks for posting this! I've been trying to use the DFSDM peripheral with the MEMS microphones on the STM32F469I-DISCO, and this clarifies a lot. I didn't know that you could switch between the different microphones by just altering the solder bridges, definitely going to give this a try.:smiling_face_with_smiling_eyes:

[AlecCT]

Hi, yes I believe this is a mistake in the F469I-DISCO datasheet, probably copied and pasted from a previous discovery board. It seems that using SAI is the intended purpose for this board, but I'm struggling to get any data read from the microphones through SAI.

I've got a timer output on pin PD13 outputting a 2.4MHz clock to the IMP34DT05 mics, and the SAI peripheral set up as a Master Receive mode with the Serial Data input set on pin PD6. When I run it in though (in basic blocking mode) I can see on an oscilloscope the mic outputting digital PDM data but the SAI times out every time and doesn't receive any data, no matter what I do with the settings in CubeMX.