During DMA transfer, the DMA controller transfers data ______.

Concept

Direct Memory Access (DMA) is a bus-mastering mechanism in which a DMA controller moves a block of data between an I/O interface and main memory. The CPU configures the transfer and is notified when it finishes, but it does not carry each data word.

Application

Here, the blank asks for the two endpoints used during the transfer phase. The DMA controller obtains bus control, reads from one endpoint, and writes to the other, so the data path is between the I/O module and main memory.

Contrast and cross-check

• CPU to memory describes the processor acting as the source of a store or copy operation.

• Memory to CPU describes a processor load in which the CPU receives a value.

• Memory and processor registers describes instruction-level load/store movement inside the processor–memory path.

• I/O module and main memory describes the DMA block-transfer path while the CPU is limited to setup and completion handling.

Result

Therefore, the DMA controller transfers data directly between the I/O module and main memory.