STM32F7 - Unable to Select I2S Mode for SAI1 in CubeMX

[Extra]

Hi: My goal is to perform full-duplex I2S using the STM32F722RET6 part. To achieve this using the pins available on the package it looks like I need to use SAI2 (sub-block B) as the master/TX and SAI1 (sub-block A) as a slave/RX synchronized to SIA2.

The configuration of SIA2 in CubeMX works fine.  However, when I attempt to configure the slave side (SAI1-A) the I2S option is greyed out (see below). Can anyone help me to debug this? Many thanks, Bruce.

[Extra]

CubeMX version is 6.17.0.

[Ghofrane GSOURI]

Hello @Extra 

It would be great if you could share your IOC in order to check your configuration and see whether there is a conflict.

I will be waiting for your feedback.

Thx

Ghofrane 

[Extra]

Hi Ghofrane:

Thanks so much for the help. I have attached my IOC file. 

Bruce

[Ghofrane GSOURI]

Hello @Extra 

I have created an internal ticket, #0062173, to request expert feedback on this behavior: the I2S/PCM Protocol option is always disabled in CubeMX. I would like to determine whether this is a tool limitation or an intentional restriction. I will keep you updated as soon as I receive any feedback.

THX

Ghofrane

[Extra]

HI Ghofrane:

Did you get any expert feedback on this question? 

Thanks,

Bruce

[Extra]

While searching the forum I found this issue from a few years back:

https://community.st.com/t5/stm32cubemx-mcus/stm32cubemx-doesn-t-seem-to-properly-support-configuring-sai1-on/m-p/285092/highlight/true#M14578

which appears to be almost identical to the problem I am experiencing. There is no resolution posted on that thread either.

Unfortunately, I am now starting to work on a "bare-metal" setup of SAI1_A since I'm not seeing any CubeMX support for this feature.

[Extra]

Adding one other thing here. 

My application uses SAI2 (sub-block B) as the master/TX and SAI1 (sub-block A) as a slave/RX synchronized to SIA2. I used CubeMX to generate the SAI2 (sub-block B) configuration and I configured SAI1 (sub-block A) by hand using register writes per the datasheet. After a lot of debug, my system is working fine and is passing audio in both directions.

Conclusion: the F722 part is capable of working in this mode. I'm not sure why CubeMX doesn't allow the configuration. The manual setup of the SAI registers took me about 4 hours to get right.