We are currently working on a custom board that uses all the three audio serials.
To do some tests, I downloaded and successfully modified the sai_interrupt_record_playback example from the SDK, but I was unable to get the same results with SAI3.
After some debugging, I discovered that the problem was in the SDK, specifically in startup_mimxrt1052.c
Around line 1042 the code reads:
WEAK void SAI3_TX_IRQHandler(void)
But the function in fsl_sai.c is in fact named:
The same typo is also present in the RX handler.
SDK is version 2.4.1