SD card is working just fine.

even FatFS library was more or less easy to setup. the only slightly jerky part was configuring the library to work with DMA.

FatFS with DMA

see FatFS + DMA

In the file, sd_diskio.c, enable the following definition:

#define ENABLE_SD_DMA_CACHE_MAINTENANCE  1 
#define ENABLE_SCRATCH_BUFFER

Note that sd_diskio.c, s given by the CubeMX, which is specific for each architecture. This particular version for the STM32H743 supports the cache memory operation, and the definition above will enable it.

I changed the win element in the struct FATFS to be a pointer to char array. In addition, accoring to cache memory requirements, the char array is allocated to be 32 bytes aligned.

static BYTE buffer[1024] __attribute__ ((aligned (32)));

I took a space of 512 to be on the safe side that invalidates cache operation won’t harm another data outside that array. To set the array in the new FATFS struct type:

FATFS fs
fs.win = buffer