How to get DMA working for the last DWORDs from SDMMCx FIFO?

[JHYBN.2056]

Hello,

I am working on SDMMC ReadBlock function using DMA with peripheral flow control enabled. When I try to transfer 512 Bytes block from the SD Card, I have last 3 DWORDs "mising" (CNDTR is 0xFF82 instead of expected 0xFF00). These DWORDs are transfered by DPSM (its DCOUNT is zero), but staying in FIFO, not transfered by DMA. So I have to transfer them by SW, instead by DMA.

Is there anyone, who knows how to persuade DMA to completely finish the transfer?

Some details about my setup:

• memory buffer is 32 Bytes aligned
• DMA burst transfer is INCR4 on both sides
• SDMMC hardware flow enabled
• transfer is finished with DATAEND flag

Thank you for any help,

Jarda

[JHYBN.2056]

If somebody is interested in ...

My DMA problem has been solved after I set-up FIFO threshold level inside DMA_SxCR register to b'11 (full FIFO). From that moment all transfers are finished automatically. It's a pitty, that I do not get this idea from manual, but I have to follow the USB-FS MSC application example...

Jarda