8237 modes-microprocessor, Assembly Language

Assignment Help:

8237 modes :

Intel 8237 can be set to four different type of style of transfer:

1) Single - One transfer at a time,  it allow processor access to the bus between transfers.

2) Block - Transfer all data, it do not allow processor access to the bus (may cause problems with memory refresh).

3) Demand - it keep transferring as long as target keeps DRQ asserted.

4) Cascade - it allow a slave controller use of the DMAC (used for DRQ4).

 

(A) In addition, the DMA controller can be set to make continuous transfers

o   It known as auto-initialized DMA

o   normally DMA is known as "single-cycle"

 

(B) 8237 is clocked at 1/2 of ISA Bus (0.5 *BLCK)

o   up to 4.166MHz (8.33 Mhz ISA)

o   Maximum transfer rate: 4.166MB/s (16-bit DMA)

o   Maximum Programmed I/O transfer rate: 2.77 MB/s

 

(C) Size of transfer

o   Master can only produce word-sized transfers

o   Slave can produce byte-sized transfers

o   Minimum transfer size: 1 byte

o   Maximum transfer size: 64KB (8-bit),128KB (16-bit)

 


Related Discussions:- 8237 modes-microprocessor

Input output memory mapped-microprocessor, Memory Mapped I/O Memory I/O...

Memory Mapped I/O Memory I/O devices are mapped into the system memory map with ROM and RAM. To access a hardware  device, simply write or  read  to  those  'special'  addresse

Assebmly code, You have to write a subroutine (assembly language code using...

You have to write a subroutine (assembly language code using NASM) for the following equation.

8086, Ask(2) Write a program to mask bits D3D2D1D0 and to set bits D5D4 and...

Ask(2) Write a program to mask bits D3D2D1D0 and to set bits D5D4 and to invert bits D7D6 of the AX register question #Minimum 100 words accepted#

Code for reading flow & generating led output, Code for Reading Flow & Gene...

Code for Reading Flow & Generating LED Output The code starts with the scanning of the PORT 3, for reading the flow status to check for various flow conditions and compare to

Assembly language, how to find out the given number is positive or negative...

how to find out the given number is positive or negative?

Input output interface-microprocessor, I/O interface I/O  devices such ...

I/O interface I/O  devices such as displays and keyboards  establish  communication of computer with outside world. Devices may be interfaced in 2 ways Memory mapped I/O and I/

Hashing, what is double hashing

what is double hashing

Call-unconditional branch instruction-microprocessor, CALL : Unconditional...

CALL : Unconditional Call:- This instruction is utilized to call a subroutine from a basic program. In case of assembly language programming, the term procedure is utilized int

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