Can you please help me what is MDMA, BDMA? What is the difference between DMA and them? Can you suggest me a good explanation document, please?

The Reference Manual, and the bus matrix diagrams.

The DMA to use would depending on the source / destination of the transfer, most usually the memory being used.

Why should I use MDMA instead of DMA? I searched and I read some documents but I am not satisfied with what I read.

• the various DMA have various bus connectivity, not every DMA can reach every memory and every peripheral, see Memory and bus architecture chapter
• the various DMA have various triggering schemes, see DMAMUX and the Block interconnect chapter
• they are various designs: MDMA is a very complex beast on the AXI, DMA are the same dual-port design as in 'F2/'F4/'F7, BDMA is the single-port design as in 'Lx/'F0/'F3

As Clive said above, read the Reference Manual, not "some documents". Yes, it's 3000+ pages long, and what. Rome wasn't built in a day. It was your choice to go for the most complex STM32 available. And you don't need to read it all, anyway, see index/bookmarks.

JW

​Hello @Ali Aldoğan​,

I recommend you to have a look to: 

https://community.st.com/s/question/0D50X0000A4nsm2SQA/mdma-vs-dma  

You can also refer to  application note: AN5001

https://www.st.com/content/ccc/resource/technical/document/application_note/group0/56/d6/da/be/34/2c/4f/94/DM00360392/files/DM00360392.pdf/jcr:content/translations/en.DM00360392.pdf

Imen,

@Community member​ , @Imen GH​ , @Community member​  Thank you. I am much more better now about rome :)