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STM32F42x/STM32f43x SAI DMA FIFO errors

Question asked by letnick.chris on Jan 16, 2014
Latest reply on Jan 27, 2014 by waclawek.jan

I have been working with an STM32F27 in an audio application. I am using the SAI module with both blocks. Block A is a master RX block, block B is a slave TX block synchronized to block A. The interface is standard phillips I2S with 32 bits per channel.

I am following the order suggested in the reference manual and enabling the DMA before the SAI. And, enabling the slave before the master.

The error I get is that as soon as I enable one of the SAI blocks, I get a fifo error (DMA_FLAG_FEIF4) from the DMA. This flag is set once and only once. If I simply clear this flag once and continue, it will not be seen again. I have the DMA in FIFO disabled mode. I tried playing around with the FIFO configuration for both the DMA and SAI block, but have not been able to get different results.

I have the easy work-around of just clearing that flag the first time it pops up. However, I am uncertain why this error is occuring.And, I lost half a day trying to figure out what was wrong before I just decided to try seeing if it was a persistent error.

Has anybody else encountered this kind of behavior, or are there any STM people out there who can comment on this?