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

How can i pass parameters to my simulation, How can I pass parameters to my...

How can I pass parameters to my simulation? A  test  bench  and  simulation  would likely  need  many  different  parameters  and  settings  for  various sorts of tests and con

Illustrate abstract class, What is an abstract class? Please, expand by exa...

What is an abstract class? Please, expand by examples of using both. Explain why?   Abstract classes are closely related to interfaces. They are classes that cannot be instanti

Define hyperlinks, Q. Define Hyperlinks? Hyperlinks, or links are one o...

Q. Define Hyperlinks? Hyperlinks, or links are one of the most significant characteristics of web pages. A link moves us from current page to a destination which is specified i

Write a short note on pointer operators in c, Write a short note on pointer...

Write a short note on pointer operators in c Pointers (that is, pointer values) are generated with the ''address-of'' operator &, which we can also think of as the ''pointer-to

What are the aspects of security policy, What are the aspects of security p...

What are the aspects of security policy The security policy should cover aspects such as network service access, physical access, limits of acceptable behaviour, company's pro

Explain the term - ancestors, Explain the term - ancestors The ancestor...

Explain the term - ancestors The ancestors of modern age computer were mechanical and electro-mechanical instruments. This ancestry can be traced as back and seventeenth centur

Engineering and managerial economics, write a short note on good blend of e...

write a short note on good blend of engineering and managerial economics

The spanning tree of connected graph with 10 vertices, The spanning tree of...

The spanning tree of connected graph with 10 vertices have 9 edges of spanning tree of connected graph with 10 vertices

What is a subroutine, What is a subroutine? A subroutine is a named, in...

What is a subroutine? A subroutine is a named, independent section of C code that performs a particular task and optionally returns a value to the calling program.

What is thread, What is Thread? A thread, sometimes termed a lightweigh...

What is Thread? A thread, sometimes termed a lightweight process (LWP), is a fundamental unit of CPU utilization; this comprises a thread ID, a register set, a program counter

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