Why is the Bus Request and Grant mechanism important in DMA (Direct Memory…
2025
Why is the Bus Request and Grant mechanism important in DMA (Direct Memory Access)?
- A.
It ensures exclusive access to memory during DMA transfer.
- B.
It minimizes register overflow.
- C.
It speeds up CPU execution.
- D.
It allows the CPU and DMA to access memory simultaneously.
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Correct answer: A
In DMA (Direct Memory Access), the DMA controller needs access to the system bus to transfer data directly between memory and I/O devices. The Bus Request (BR) signal is sent by the DMA controller to request control of the bus. The CPU responds with a Bus Grant (BG) signal, temporarily releasing control. This mechanism is important because it ensures exclusive and conflict-free access to memory during DMA transfers.