DMA CONTROLLER
ARCHITECTURE OF 8085
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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DRQ0-DRQ3
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DACKo-DACK3
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Do-D7
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Ao-A3
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Detailed explanation-1: -The chip support four DMA channels, i.e. four peripheral devices can independently request for DMA data transfer through these channels at a time.
Detailed explanation-2: -Using a DMA controller, the device requests the CPU to hold its data, address and control bus, so the device is free to transfer data directly to/from the memory. The DMA data transfer is initiated only after receiving HLDA signal from the CPU.
Detailed explanation-3: -Cycle Stealing Mode: In DMA’s cycle stealing mode of operation, the DMA controller puts the CPU on hold for each byte of data to be transferred.
Detailed explanation-4: -Each channel can be programmed independently. operations. It operates in 2 modes, i.e., Master mode and Slave mode. These are the four individual channel DMA request inputs, which are used by the peripheral devices for using DMA services.