What happens during DMA transfer?
- 9 Answers
- 27754 Views
- I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / raghu
DMA means Direct memory access which is used to share the
bulk of data without involving of microprocessor. in this
process the microprocessor will be idle and it uses +5V
power supply.
| Is This Answer Correct ? | 34 Yes | 3 No |
Answer / geo
during dma transfer the processor is going with its current
processes and not involved with the data transfers ,since it
already released its buses the for that ...
| Is This Answer Correct ? | 24 Yes | 6 No |
Answer / niaz mohammad
DMA (Direct Memory Access) is a technique that transfers
data between a microprocessor's memory and an I/O device
without involving the microprocessor.
* Working process of DMA controller:
1. The I/O device request DMA operation via the DMA request
lines of the controller chip.
2. The controller chip activates the microprocessor HOLD
pin, requesting the CPU to release the bus.
3. The processor then sends HLDA (Hold Acknowledgement) back
to the DMA controller.
4. The DMA controller completes the DMA transfer and
releases the bus.
| Is This Answer Correct ? | 14 Yes | 0 No |
Answer / vinay m k
During DMA transfers DMA manager takes control of the
transfer of data from specified source address to
destination address. 1D-1D or 1D-2D or 2D-1D or even 2D-2D
transfers are usually possible. During this time processor
is free to perform other operations - which are independent
of the impending transfer being performed.
http://www.vinaymk.com/tutorials
| Is This Answer Correct ? | 14 Yes | 3 No |
Answer / ravi
During dma operation data tranfer takes place directly to
the peripheral devices,MPU releases the control of the
buses to the dma controler and two new signals are comes
into existence,(1)hold (2)hlda(hold acknowledge)
| Is This Answer Correct ? | 13 Yes | 2 No |
Answer / umuntu
THE DMA use the data bus and the microprocessor is not
involved but during this time it can do other tasks which
do not require the data bus such as ALU operation,..
| Is This Answer Correct ? | 7 Yes | 5 No |
Answer / padmapriya.c
The CPU communicates with the DMA through the address and
data buses as with any interface unit. The DMA has its own
address, which activates the DS and RS lines. The CPU
initialize the DMA through the data bus. Once the DMA
receives the start control command, it can start the
transfer between the peripheral device and the memory
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / aromal
At the time of DMA operation the micro processor can do any
other task
| Is This Answer Correct ? | 9 Yes | 14 No |
Answer / justin
the processor can do any task other task during dma operation
| Is This Answer Correct ? | 0 Yes | 15 No |
Can you name the different types of processor?
What is coprocessor?
How is the system clock calculated in the 8085?
What is the maximum clock frequency used by the 8085 microprocessor?
What is the bus arbitration problem in the 8086 and how can it be resolved?
What is 'daisy-chaining' in reference to the 8086?
Explain the addresses which are bit addressable?
What all does a microprocessor comprise of?
Can single bit of a port be accessed in 8051?
State the two type of 16 bit registers and define them?
What is segment address in 8086?
Give a circuit to divide frequency of clock cycle by two ?
86 Family 
