Is there a trade-off for memory to memory DMA transfer when the data size is small?

Question

I am learning about the STM32 F4 microcontroller. I\'m trying to find out about limitations for using DMA.

Per my understanding and research, I know that if the data si

Answer 1

DMA -CPU puts all its lines at high impedance state

I do not know where did you take it from - but you should not use this source any more.

Frequency of the DMA transfers do not matter unless you reach the the BUS throughput. you can transfer one byte per week, month, year, decade ..... and it is absolutely OK.

In the STM32 microcontrollers it is a very important feature as we can transfer data from/to external devices even if the uC is in low power mode with the core (CPU) sleeping. DMA controller can even wake up the core when some conditions are met.