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Input\Output in Computer System - Coggle Diagram
Input\Output in Computer System
I/O Module
Program,operation or device that transfers data to or from computer and to or from a peripheral device
Input device: Mouses, Keyboard and etc..
Output Device: Printer, Projector and etc..
Input/Output device: CD-ROM, Modem
I/O Module Function
Interface with the CPU and memory via the system bus/Central switch
Interface with one or more peripheral devices by tailored data links
Input/Output Data Transfer
Asynchronous Serial transfer
consists of start bit,character bits, and stop bits.
Start bit is always a 0 and used to indicate the beginning of character
Stop bit is always a 1.
Character oriented
Binary information is sent only when it is available
The line remains idle when there is no information to be transmitted
Asynchoronous communication Interface
The transmission of data without the use of an external clock signal
most significant aspect is variable bit rate
Characteristic of isolated and memory mapped I/O
Isolated I/O
Can read and write one to four bytes to an I/O device
Large selection of memory access commands avaiable
Memory Mapped I/O
The processor and the I/O device share the same memory location
Need more I/O or memory select lines
Transfer mode
Programmed I/O
The method od transferring data between the CPU and peripheral such as a network adapter/ATA storage device
It Happens when software running on the CPU uses instructions that access I/O address sapce to perform data transfer to or from an I/O device
Interrupt-Initiated I/O
Overcome CPU waiting
No repeated CPU checking of device
I/O module interrupts when ready
Direct Memory Access
a method of transferring data between peripherals and memory without using CPU
DMA controller periodically takes over conrol of the system bus from the CPU
DMAC generates address, data and control signals to transfer data between memory and I/O devices
the I/O controller has the ability to transfer data directly to/from the memory without involving the processor