Dma-how dma works-microprocessor, Assembly Language

Assignment Help:

DMA

  • DMA stands for Direct Memory Access
    • It is uses same Address/Data lines on ISA bus
    • It controls the ISA bus instead of the processor ("bus master")
    • Floppy Drive (DRQ2)
    • Hard Drive (varies)
    • Sound Card (varies)

 

  • DMA vs. Programmed I/O
    • It need less processor load
    • It can continually transfer the same block (loop indefinitely)
    • The devices which are demand-based can be serviced more efficiently

     

  • DMA characteristics:
    • It is 16-bit or 8-bit transfers

 

HOW DMA WORKS to transfer data from memory to a peripheral:

1. The peripheral Device requests for DMA service by pulling DREQ line high

2. The DMA controller requests CPU go on hold by pulling CPU's HRQ line high

3. The CPU finished current bus cycle, then acknowledges with HLDA the CPU relinquishes ALL bus control now (3-state)

4. The DMA controller activates DACK line to acknowledge the DMA to the peripheral

5. The DMA start transferring data to the peripheral

 


Related Discussions:- Dma-how dma works-microprocessor

Assembly - Zombie Game using Irvine & Visual 2010, http://www.raritanval.ed...

http://www.raritanval.edu/uploadedFiles/faculty/cs/full-time/Brower/CISY256/2013Spring/CISY256%20Assembly%20Project.pdf

Rics/cisc architecture-microprocessor, RICS/CISC Architecture An essent...

RICS/CISC Architecture An essential aspect of computer architecture is the design of the instruction set for the processor.  The instruction set selected for a specific compute

Third generation microprocessor, III rd Generation Microprocessor: T...

III rd Generation Microprocessor: The single 3rd generation microprocessor chip having 64-pins began with the introduction of 16-bit Intel 8086 in 1978. The other essential

The alpha, The Alpha : The development of the Alpha chip start in the y...

The Alpha : The development of the Alpha chip start in the year 1988 The new chip used 64 bit technology, let users to pack  more  complexity  into  their  programs  than  exis

Write an assembly program to find out largest number, Program :  Write an...

Program :  Write an assembly program to find out the largest number from a given unordered array of 8-bit numbers that stored in the locations starting from a known address. S

The real time system (rts)-microprocessor, The real time System (RTS) : ...

The real time System (RTS) : Calling the clock real-time is somewhat of a misnomer because it only shows the time setting it has been given. The RTC is the other half of chip

Write a mips assembly language program, Write a MIPS/SPIM assembly language...

Write a MIPS/SPIM assembly language program that prints the smallest and largest values found in a non-empty table of N word-sized integers. The address of the first entry in your

Addsub, Using the AddSub program from Ch3 under c:\Masm615\examples as a re...

Using the AddSub program from Ch3 under c:\Masm615\examples as a reference, write a program that subtracts three 16-bit integers using only registers. Insert a call DumpRegs statem

Iret-loop-unconditional branch instruction-microprocessor, IRET : Return f...

IRET : Return from ISR:- When an interrupt service routine is called, before transferring control to it, the IP, CS  register and flag registers are stored in the stack to ment

Org-proc-assemblers directive-microprocessor, ORG : Origin:- The ORG di...

ORG : Origin:- The ORG directive directs the assembler to begin the memory allotment for the specific segment, code or block from the declared  address in the ORG  statement. W

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