DMA CONTROLLER
ARCHITECTURE OF 8085
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Interrupts
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Memory mapping
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DMA
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Program-controlled I/O
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Detailed explanation-1: -In conclusion, DMA is the best method for high-speed I/O transfers. DMA offers faster data transfer, reduced CPU overhead, efficient use of CPU time, and lower power consumption. DMA is a hardware-based method that allows the I/O device to access the computer’s memory directly without the intervention of the CPU.
Detailed explanation-2: -DMA controller transfers the data block at the faster rate as data is directly accessed by I/O devices and is not required to pass through the processor which save the clock cycles. DMA controller transfers the block of data to and from memory in three modes burst mode, cycle steal mode and transparent mode.
Detailed explanation-3: -Its module is faster than the programmed I/O module.
Detailed explanation-4: -1) Burst or block transfer DMA It is the fastest DMA mode. In this two or more data bytes are transferred continuously. Processor is disconnected from system bus during DMA transfer.
Detailed explanation-5: -This technique overcomes the drawbacks of other two I/O techniques which are the time consuming process when issuing command for data transfer and tie-up the processor in data transfer while the data processing is neglected. It is more efficient to use DMA method when large volume of data has to be transferred.