Explain functions of direct memory access, Computer Engineering

Assignment Help:

Q. Explain functions of direct memory access?

Though CPU intervention in DMA is minimised however it should use path between interfaces that is system bus. So DMA involves an extra interface on system bus. A scheme known as cycle stealing permits DMA interface to transfer one data word at a time, after that it should return control of bus to processor. Processor merely delays its operation for one memory cycle to permit directly memory I/O transfer to 'steal' one memory cycle. When an I/O is requested processor issues a command to DMA interface by transmitting to DMA interface the subsequent information (Figure below): 

  • Which operations (write or read) to be performed using write or read control lines.
  • Address of I/O devices that is to be used communicated on data lines.
  • Starting location on memory where information will be read or written to be communicated on data lines and is stored by DMA interface in its address register.
  • Number of words which are to be read or written is communicated on data lines and is stored in data count register.

927_Explain functions of direct memory access.png

Figure: DMA block diagram


Related Discussions:- Explain functions of direct memory access

What are the input for uml development, What are the Input for UML developm...

What are the Input for UML development UML is an attempt to standardize artefacts of analysis and design consisting of semantic models, diagrams and syntactic notations. The fi

Determine about the memory stack, Memory Stack Stack could exist as a s...

Memory Stack Stack could exist as a stand-alone unit or could be executed in a random-access memory attached to the CPU. The implementation of a stack in a CPU is done by assig

Explain working of counters, Q. Explain working of Counters? A counter ...

Q. Explain working of Counters? A counter is a register that goes through a predetermined sequence of states when clock pulse is applied. In principle value of counters is incr

Illustrate clock signals of clock pulse generator, Q. Illustrate Clock sign...

Q. Illustrate Clock signals of clock pulse generator? Synchronization in a sequential circuit is attained by a clock pulse generator that gives continuous clock pulse.  Figure

How can we send data to external programs, How can we send data to external...

How can we send data to external programs? Using SPA/GPA parameters(SAP memory). Using EXPORT/IMPORT data (ABAP/4 memory)

Applications of electronic data interchange in business, What are the appli...

What are the applications of Electronic Data Interchange in business? The applications of Electronic Data Interchange are as given below: 1. Organisations that use EDI 2

An example subroutine call, Create your own Subprogram that does *not* use ...

Create your own Subprogram that does *not* use any input parameters. You decide the theme. You should give the pseudocode and an example Subroutine call. Be sure to give an overvie

Write short note on quantization, Write short note on Quantization. Qua...

Write short note on Quantization. Quantization: This is the first step in PCM. The whole amplitude range of the modulating signal is divided in a number of standard levels term

Elements of composition, The Elements of composition are the formal languag...

The Elements of composition are the formal language used to communicate in the visual arts. The elements of composition can be loosely broken into 5 main elements, Line, shape, val

Cache simulater, Requirements You are required to program (in a high l...

Requirements You are required to program (in a high level language such as C, C++, Java) and implement a cache simulator which will have the following inputs and outputs:-

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd