BDMA double buffer mode on STM32H7xx Rev. Y
Posted: Tue Mar 16, 2021 9:07 pm
Hi,
I'm currently working on a project based on a STM32H743 that needs all 4 SAI units running simultaneously at 48kHz sample rate. Each SAI block has to handle 8 audio samples at 24bit. IMHO the only way to handle this much data is to implement a zero-copy scheme based on the DMA double buffer mode. According to the datasheet DMA1, DMA2 as well as BDMA support double buffer mode on STM32H7xx. However the BDMAv1 driver only activates this for the newer revisions of the MCU.
Unfortunately our prototype boards are a little bit older and therefore use the old revision Y (Rev.ID 0x1003). Since i couldn't find any document that suggests BDMA double buffer mode is only available on newer revision of the MCU, i patched the BDMAv1 driver (see attachment) to test it. Using this patch everything works as expected. Is there a reason why double buffer mode is deactivated for revision Y?
regards
christian
I'm currently working on a project based on a STM32H743 that needs all 4 SAI units running simultaneously at 48kHz sample rate. Each SAI block has to handle 8 audio samples at 24bit. IMHO the only way to handle this much data is to implement a zero-copy scheme based on the DMA double buffer mode. According to the datasheet DMA1, DMA2 as well as BDMA support double buffer mode on STM32H7xx. However the BDMAv1 driver only activates this for the newer revisions of the MCU.
Code: Select all
#if !defined(STM32_ENFORCE_H7_REV_XY)
#define STM32_BDMA_CR_DBM BDMA_CCR_DBM
#define STM32_BDMA_CR_CM BDMA_CCR_CT
#endif
Unfortunately our prototype boards are a little bit older and therefore use the old revision Y (Rev.ID 0x1003). Since i couldn't find any document that suggests BDMA double buffer mode is only available on newer revision of the MCU, i patched the BDMAv1 driver (see attachment) to test it. Using this patch everything works as expected. Is there a reason why double buffer mode is deactivated for revision Y?
regards
christian