RM0433, DMA/BDMA: Wrong memory region as source/target will set FIFO error!

Uwe Bonnes · ‎2018-07-26

While bringing up DMA on H743 in my code, I painfully found out that specifying a wrong memory region as DMA target, like ITCM for DMA transfers, will also set a FIFO error and abort transmission. RM0433 should mention wrong SRAM source or target regions as possible cause for a FIFO error.

Please clarify the reference manual.

Amel NASRI · ‎2018-08-01

Hi @Uwe Bonnes ,

There is no FIFO for BDMA.

However, to get more details about FIFO when using DMA, please refer to AN4031 (https://www.st.com/content/ccc/resource/technical/document/application_note/27/46/7c/ea/2d/91/40/a9/DM00046011.pdf/files/DM00046011.pdf/jcr:content/translations/en.DM00046011.pdf).

That is true STM32H7 isn't yet supported in the application note, but almost the same behavior is described there.

-Amel

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Uwe Bonnes · ‎2018-08-02

I think your answer did not get the point of my question. The question was not about FIFO mode. Even in direct mode, H743 DMA will flag a FIFO error when a wrong memory region is specified as target for the DMA. "RM0433 should mention wrong SRAM source or target regions as possible cause for a FIFO error."