INTRODUCTION TO MICROPEOCESSOR
MICROCOMPUTER SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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8086
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8237
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8251
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8253
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Detailed explanation-1: -8237 DMA Controller is a peripheral core for microprocessor systems. It controls data transfer between the main memory and the external systems with limited CPU intervention.
Detailed explanation-2: -Once a channel requests a DMA service, the 8237 sends the HOLD request to the CPU using its HRQ pin. If the CPU acknowledges the hold request on HLDA, the 8237 enters an active cycle. In the active cycle, the actual data transfer takes place in one of the following transfer modes as is programmed.
Detailed explanation-3: -Computers that have DMA channel can transfer data to and from devices much more quickly than computers without DMA channel. The difference between 8237 and 8257 is that, 8237 provides better performance than 8257.