memory to memory DMA transfer

[Cl.1]

Hi all, i want to ask about except from the reference manual where can i find out more question about the memory to memory DMA transfer.

I want to figure out is there trade-off for memory to memory DMA transfer when the data size is big and small?

Regards,

[waclawek.jan]

Tradeoff between what and what?

JW

[Cl.1]

trade of between memory to memory

[PMath.4]

Memory to memory DMA takes time to set up so for smaller transfers it will be slower than normal CPU. If speed is really an issue and you don't mind a blocking transfer then, depending on the processor, there are techniques that are even faster than DMA. Google _Z10copy_wordsPKmPmm

[Cl.1]

In my understanding the CPU need to receive data, tempeorarily store data and then transfer data. In general, as long as the data size transferred is small, even though CPU requires multiple step but still faster than DMA?