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

Zero flag, Zero flag: The next line compares the value in register. A ...

Zero flag: The next line compares the value in register. A with the value 1. If they are equivalent, the Zero flag is set (to 1). The next line then jumps to start: only if th

Program for declare the threshold, 1. Start your program at address $8500. ...

1. Start your program at address $8500. To do this you need to inform the assembler, through the EQU and ORG assembler directives, that you want your program to start at $8500. Thi

Assembler directives and operators-microprocessor, Assembler Directives and...

Assembler Directives and Operators The major advantage of machine language programming is directly that the memory control is in the hands of the programmer, so that, he can be

Computes the integral square root - assembly program, Computes the integral...

Computes the integral square root: Problem: Square Root:   For this problem you will write a short assembly program that computes the integral square root of an input numb

Program to add 8-bit series numbers-assembly language, Program: Write a pr...

Program: Write a program to perform addition of a series of 8-bit numbers. The series have 100 (numbers). Solution : In the first program, we have been implemented the add

Linking a program-microprocessor, Linking a program The DOS linking pro...

Linking a program The DOS linking program LINK.EXE links the different object modules of function library routines and source program to produce an integrated executable code o

Pointer and index registers-microprocessor, Pointer and Index Registers ...

Pointer and Index Registers The pointers contain offset within the specific segments. The pointers BP, IP and SP generally containoffsets within thedata, code and stack segment

Matrices, code to add two matrices

code to add two matrices

4 bit 2s complement multiplier, How to design 4 bit signed 2s complement m...

How to design 4 bit signed 2s complement multiplier?

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