Posted on July 26, 2016 at 13:16Cube examples don't consider the fact that STM32F7 has data cache (L1). This leads to many cache coherency problems when DMA transfers are used. Some examples work only by some miracle, trying to move that code to other project leads to strange failures.
Try disabling data cache in main.c. If the code works, this is the reason (though, the syste will become very slow). Then enable the D-cache back, and consider adding SCB_CleanDCache_by_Addr() call
right before DMA write, and SCB_InvalidateDCache_by_Addr()
right after DMA reads.
Also, ensure that all data buffers used in your code for DMA transfers are aligned to 3
2 byte boundary. Find USBD_MSC_BOT_HandleTypeDef definition in the usbd_msc.h, e and move its bot_data[] buffer to the very beginning of the structure. Then, remove USBD_malloc and USBD_free calls in the code, use pointer to the 32-byte aligned static USBD_MSC_BOT_HandleTypeDef variable instead.
