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MICROPROCESSOR INTERFACING

DMA-Direct Memory Access

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DIRECT MEMORY ACCESS (DMA)

All input/ output data transfer have to pass

through the CPU.

For large data, intermediate stops inmicroprocessor consume a lot of time.

DMA is introduced to speed up data transfers

between memory and certain peripheral

devices

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DMA (CONT.)

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DMA (CONT.)

DMA bypasses the CPU for certain types of data

transfers, thus eliminating the time consumed

by normal fetch and executes cycles requiredfor each read or write operation.

For direct memory transfer, DMA controllertakes control of the system buses and allow

data to flow directly between memory and theperipheral device.