Download presentation
Presentation is loading. Please wait.
Published byEdmund Owen Modified over 9 years ago
1
COMPUTER ORGANIZATIONS CSNB123 NSMS2013 Ver.1Systems and Networking1
2
COMPUTER ORGANIZATIONS CSNB123 Overview Input/Output devices: external / peripheral devices NSMS2013 Ver.1Systems and Networking2
3
COMPUTER ORGANIZATIONS CSNB123 Importance of Peripheral Devices Interaction between computer and the outside world – make it functional NSMS2013 Ver.1Systems and Networking3
4
COMPUTER ORGANIZATIONS CSNB123 I/O Modules Contains logic perform communication function between the peripheral and the bus Interface to the system bus/central switch Control peripheral devices NSMS2013 Ver.1Systems and Networking4
5
COMPUTER ORGANIZATIONS CSNB123 Importance of I/O Module Varieties of peripheral devices various operation Not practical – burden the processor Hard to control – data transfer rate is slower than processor and memory Use different data formats and word lengths NSMS2013 Ver.1Systems and Networking5
6
COMPUTER ORGANIZATIONS CSNB123 Major Function of I/O Interface to the processor and memory via system bus/central switch to one/more peripheral devices NSMS2013 Ver.1Systems and Networking6
7
COMPUTER ORGANIZATIONS CSNB123 External Device (ED) ED connected to computer by a link to an I/O module Use of link; Exchange; Status Control Data NSMS2013 Ver.1Systems and Networking7
8
COMPUTER ORGANIZATIONS CSNB123 Classification of ED NSMS2013 Ver.1Systems and Networking8
9
COMPUTER ORGANIZATIONS CSNB123 Interface to I/O Module NSMS2013 Ver.1Systems and Networking9
10
COMPUTER ORGANIZATIONS CSNB123 Interface to I/O Module (Cont.) NSMS2013 Ver.1Systems and Networking10 TermDescription Control logiccontrols the device’s operation Transducerconverts data; From electrical to other forms of energy (output) From other forms to electrical (input) Bufferrelated to transducer- hold data temporarily, size 8 to 16 bits
11
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module NSMS2013 Ver.1Systems and Networking11
12
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module (Cont.) To coordinate the flow of traffic between internal resources and ED E.g. data transfer from ED to CPU Check device status - CPU ask I/O module I/O module returns device status Ready – CPU request data I/O module get data from ED Transfer data NSMS2013 Ver.1Systems and Networking12
13
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module (Cont.) To communicate between internal resources and ED Operations; Command decoding Accept command from CPU send to control bus Data Exchange between CPU and I/O module over data bus Status reporting Status of ED Address recognition Know address for each I/O device NSMS2013 Ver.1Systems and Networking13
14
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module (Cont.) The I/O module must able to perform DC Operations; Command Data Status information NSMS2013 Ver.1Systems and Networking14
15
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module (Cont.) Data comes from main memory in rapid burst and must be buffered by the I/O module, then send to the device at device’s rate NSMS2013 Ver.1Systems and Networking15
16
COMPUTER ORGANIZATIONS CSNB123 Categories of Major Function for I/O Module (Cont.) I/O module responsible for; error detection Transmission error report errors to the CPU NSMS2013 Ver.1Systems and Networking16
17
COMPUTER ORGANIZATIONS CSNB123 I/O Module Structure TermDescription System busConnect I/O module to the computer Data registersBuffer the in/out data into/from I/O module Status/Control registers Provide register’s status Control signal lines Allow I/O module logic interacts with CPU CPU issue command to the IO module Address linesKnow and generate device’s address External device interface logic Device interfaces to the device it’s control I/O channel / processor Handle detail processing burden I/O LogicUsed in primitive I/O module NSMS2013 Ver.1Systems and Networking17
18
COMPUTER ORGANIZATIONS CSNB123 Programmed I/O Direct Memory Access (DMA) Interrupt Driven I/O NSMS2013 Ver.1Systems and Networking18
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.