Question

To indicate the I/O device that its request for the DMA transfer has been honored by the CPU, the DMA controller pulls

(a) HLDA signal

(b) HRQ signal

(c) DACK (active low)

(d) DACK (active high)

I have been asked this question in quiz.

I would like to ask this question from DMA Transfers and Operations topic in section DMA, Floppy Disk and CRT Controllers of Microprocessor

Answer 1

Right option is (c) DACK (active low)

Easiest explanation: The DACK (active low) line of the used channel is pulled down by the DMA controller to indicate the I/O device that its request for the DMA transfer has been honored by the CPU.