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

Show the properties of frame tag, Q. Show the properties of Frame Tag? ...

Q. Show the properties of Frame Tag? This tag is used for placing an HTML file in the frame created. We should now tell browser what to put in every frame.

Differences between inter statement and intra statement, Differences betwee...

Differences between inter statement and intra statement delay? //define register variables reg a, b, c; //intra assignment delays initial begin a = 0; c = 0;

Explain their characteristics and limitations of grammar, Identify the diff...

Identify the different classes of grammar. Explain their characteristics and limitations. As proposed through Noam Chomsky that Chomsky hierarchy contains the subsequent level

What are the applications of edi in business, What are the applications of ...

What are the applications of EDI in business A.  Organistions that use EDI Extensive users of EDI contain: BHS- is a UK and European retailer dealing majorly in appare

Difference between packet switching and circuit switching, What are the adv...

What are the advantages and disadvantages of packet switching over circuit switching? The comparison of packet switching and circuit switching demonstrating advantages and disa

What does the term entrepreneurship mean, 1) What does the term entrepreneu...

1) What does the term entrepreneurship mean to you?  What are some basic characteristics of entrepreneurs? 2) What is e-commerce?  Why are the Internet economy and e-commerce he

Describe the von neumann architecture, Describe the VON NEUMANN ARCHITECTUR...

Describe the VON NEUMANN ARCHITECTURE Most  of  present  computer  designs  are  based  on  idea  developed  by  John  vonNeumann referred to as the VON NEUMANN ARCHITECTURE. V

Direct isp service through leased line, The most expensive method of access...

The most expensive method of accessing Internet is to use leased lines which connect directly to the ISP. This will increase access rate to anywhere between 64 K and 1.5 Mbps, rely

Direct mapped strategy, Determine the layout of the specified cache for a C...

Determine the layout of the specified cache for a CPU that can address 1G x 32  of memory.  show the layout of the bits per cache location and the total number of locations.  a)

Microprocessor and interfacing, Write an ALP to count positve and numbers f...

Write an ALP to count positve and numbers from array.

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