M2M DMA Transfert Doesn't allign with the specifications

[Rayen_Bouafif]

Hey , New to STM32 Here
I was learning about the different DMA modes, and I came across a study case that compares the time taken by each mode in a DMA memory-to-memory transfer (from Flash to SRAM). Here's the comparison below:

I'm using a Nucleo-F401, and I wrote a simple code to measure the transfer time using a timer, like this:

I was surprised that the results were not as expected — for example, DMA MEM2MEM transfers with word alignment took longer than those with byte alignment. Can someone please explain because this is so confusing 

[Rayen_Bouafif]

I'm using Direct Mode : 

Byte-Alignment = 45μs

Word Alignment = 48μs

[Rayen_Bouafif · Accepted solution]

Solved

[AScha.3]

Hi,

where is the table from ?

+

What you found?

solution ?

[Rayen_Bouafif]

In fact , It was a dumb mistake haha , as you can see im transferring 1000 element (counter = 1000) , when I changed the data alignement to word , I forgot to set the counter to 250 element (250 x 4 = 1000 byte) That's it !