Question

What is function of DMA? Explain DMA controller operation with a neat diagram.

Answer 1

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I am here with your answer!

Direct memory access (DMA) is a method that allows an input/output (I/O) device to send or receive data directly to or from the main memory, bypassing the CPU to speed up memory operations. The process is managed by a chip known as a DMA controller (DMAC).

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Answer 2

Function of DMA:

• DMA is a direct way to access the memory without any external device help.
• It is the common hardware function within the system that is used to relieve the processor or coprocessor from the burden of copying large blocks of data.
• It allows an input/ouput device to send /receive data.

DMA Controller Operation:

• An I/O device operates at a much speed than the core. DMA saves cre MIPS because the core can operate parallely.
• It saves power because it requires less circuitary than the core to move data.
• When device sends data between the device and memory, the device has to send DRQ request to DMA controller.
• The DMA controller sends HRQ to the CPU and waits for the CPU to assert HLDA.