INPUT/OUTPUT

Assalamualaikum and hello guys!
This post will discuss about new topic.This topic is about input and output computer organization.In this topic there all have six subtopic.But today i will not discuss all the subtopics.I will just discuss about accessing I/O devices.

OUTLINE

>Accessing I/O devices

>Interrupts                

>Direct memory access

>Buses                      

>Interface circuits       

>Standard I/O            

interfaces          

  

CONTENT COVERAGE

ACCESSING I/O DEVICES

>Single-bus structure

• The bus enable all the devices connected to it to exchange information.
• consists of three sets of lines used to :- 

         - carry address 

         - data

         - control signals

• Each I/O devices is assigned a unique set of addresses

I/O MAPPING

Memory mapped I/O

>Devices and memory share an address space 

>I/O looks just like memory read/write 

>No special commands for I/O

• large selection of memory access commands available

Isolated I/O

>Separate address spaces

>Need I/O or memory select lines 

>Specials commands for I/O

• limited set

MEMORY-MAPPED I/O

>I/O devices and the memory share the address space,so the arrangement is called      memory-mapped I/O

>Any machine instruction that can access memory can be used to transfer data or from an  I/O device using memory-mapped

>Most computer system use memory-mapped I/O

>Some processor have special IN and OUT instructions to perform I/O transfers

I/O INTERFACE FOR AN INPUT DEVICE

NURFARAH ALIA BINTI KAMARUDDIN 

B031310432