PDM settings for STM32H SAI ports gives me a conflict warning.

[BHan.1]

I'm using STM32H743ZIT6 for an audio speaker, and while I was trying to set SAI1 for a DAC I2S connection and SAI4 for a PDM digital mics, CubeMX keeps giving me this error for PDM setting.

Settings

SAI1 A&B is set for Asynchronous I2S

SAI4 A is set for PDM (2 D-MIC)

The warning is that the Mode of SAI4 conflicts with SAI1 Asynchronous Slave mode, but I couldn't find what this meant.

I want to keep the ports because it gives me the best placement of ICs, but I'm not sure if this is possible.

Does anyone know if SAI1 and SAI4 have to be synced in modes to use PDM?

[Khouloud OTHMAN · Accepted solution]

Hello  BHan.1,

When you set SAI1 A & B for "Asynchronous Slave", it creates a conflict with certain modes of SAI4 A & B. Those modes are unavailable they can't be selected:

- "Master"

- "Master with master clock out"

- "Asynchronous Slave"

- "Pulse Density Modulation using MicroPhones pairs (1-2) and CK2 as clock"

Otherwise it is possible to set SAI4 A to either:

• "SPDIF TX Transmitter" 
• "Synchronous Slave" 
• "Pulse Density Modulation using MicroPhones pairs (1-2) and CK1 as clock"

and SAI4 B to either :

• "SPDIF TX Transmitter" 
• "Synchronous Slave" 

This conflict is due to pin assignment, for more information you can refer to STM32H742xI/G STM32H743xI/G Dtasheet ( https://www.st.com/resource/en/datasheet/stm32h743bi.pdf )

BR,

Khouloud.

[BHan.1]

Hello Khouloud,

Thanks for checking. Even though there is a waning sign, the available option is good enough for me.

I will go with my original plan and see how it goes.

Regards,

Brian