In a system with multiple processors sharing a common bus, what is the primary…
2025
In a system with multiple processors sharing a common bus, what is the primary role of a Bus Grant signal when sent to a processor?
- A.
It allows the processor to access memory directly without bus arbitration.
- B.
It grants the processor exclusive access to the bus for communication.
- C.
It signals the processor to disconnect from the bus for DMA access.
- D.
It instructs the processor to flush its cache before accessing the bus.
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Correct answer: B
In a multiprocessor system sharing a common bus, only one master device (such as a processor or DMA controller) can control the bus at any given time to avoid data collisions.
When a processor wants to use the bus, it sends a Bus Request (BR) signal to a centralized bus arbiter. Once the arbiter determines it is that processor's turn, it responds by sending a Bus Grant (BG) signal. This signal explicitly informs the processor that it now has exclusive control over the bus to perform its read or write operations safely.