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COMPANY LOGO
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OVERVIEW
1
Introduction of bus lines2
Introduction of typical buses3
Conclusion4
Setting the problem
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Setting the problems
How to connect components in the processor such as hard disks, memory, sound system, video system and so on?
How many parts are there in the modern bus system?
What should we know the bus?
How many kinds of bus?
What are some typical buses?
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I/O Bus
I/O Bus
PCI Bus (1993)
ISA Bus (1981)
AT Bus (1987)USB Bus (2000)
PCI Express Bus (2004)
AGP Bus (1996)
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Understanding bus
Concept of bus system
Purpose of using bus
Characteristics of bus
Advantages of bus
Disadvantages of bus
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Concept of bus
A bus in the computing is the set of physical connection(cable, printed circuits, ...) which can be share by multiple hardware components in order to communicate with one another.
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Purpose of using bus
The purpose of using bus is to reduce the
number of “pathways” needed for
communication between the components, by
carry out all communication over a single
data channel.
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Characteristics of Bus
The amount of information that can be transmitted at once.
This amount, expressed in bit, corresponds to the number of physical lines over which data is sent simultaneously.
The bus speed is also defined by its frequency (expressed in Hertz), the number of data packets sent or received per second.
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Bus disadvantages
The major disadvantage of a bus is that it creates a communications bottleneck.
A bus limits the maximum I/O throughput.
For high performance systems, designing a bus system capable of meeting the demands of the processor is a major challenge.
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Bus Advantages
Two major advantages of a bus organization are:
Low cost: a single set of wires is shared between multiple cores
Versatility: new cores can be added easily and cores can be reused in a different design if the bus interface is the same
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Bus Classification
3 ways to classify kinds of bus: Base on signal function:
• Address bus• Data bus• Control bus
Base on speed:• VXL bus• Processor bus• I/O bus
Base on operation rules• Synchronous bus• Asynchronous bus
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ADDRESS BUS
Computer bus (a series of lines connecting two or more devices) used to specify a physical address
Consists of all the signals necessary to define any of the possible memory address locations within the computer, or for modular memories any of the possible memory address locations within a module
Defined as a label, symbol, or other set of characters used to designate a location or register where information is stored
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ADDRESS BUS (cont)
An address must be transmitted to memory over the address bus before data or instructions can be written into or read from memory by the CPU or I/O sections
The width of the address bus determines the amount of memory a system can address
Example:
a system with a 32-bit address address 232 (4,294,967,296) memory locations.
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DATA BUS
Function: the bidirectional data bus, sometimes called the memory bus, handles the transfer of all data and instructions between functional areas of the computer
Only transmit in one direction at a time
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DATA BUS
Transfer instructions from memory to the CPU for
execution. It carries data (operands) to and from the CPU
and memory as required by instruction translation
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CONTROL BUS
Used by the CPU to direct and monitor the actions of the other functional areas of the computer
Used to transmit a variety of individual signals (read, write, interrupt, acknowledge …) necessary to control and co-ordinate the operations of the computer
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Typical buses – ISA Bus
Some focused information: ISA = Industry Standard Architecture ISA was a computer bus standards for IBM
compatible computers.
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Typical buses – ISA Bus
Some focused information: The ISA bus was developed by a team lead
by Mark Dean at IBM as part of the IBM PC project in 1981.
ISA bus is the oldest, slowest and soon to become obsolete I/O bus system.
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Typical buses – ISA Bus
Some focused information: Is used with sound cards, disk drives or most
network and video cards.
8-bit ISA (XT) card 16-bit ISA card
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Typical buses – ISA Bus
History: In 1981, it appeared on the first PC the 8-bit
ISA bus ran at a modest 4.77 – the same speed as the processor.
In 1982, it was extended for the XT (X-Tended Technology) system architecture.
In 1984, the newer 16-bit standard, the IBM AT bus, was introduced.
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Typical buses – ISA Bus
History: In1988, ISA was improved to 32-bit EISA
(Extended Industry Standard Architecture) standard and renamed the AT bus.
In 1990s, most ISA cards remained as 8-bit technology.
Now, in late 2008, the extinction of vestigial ISA from chipsets may be on the horizon
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Typical buses – ISA Bus
Bus width 8 – bit
Compatible with
8 bit ISA
Pins 62
Power +5 V, -5 V, +12 V, -12V
Clock 4.7727266 MHz
Bus width 16 – bit
Compatible with
16 bit ISA
Pins 98
Power +5 V, -5 V, +12 V, -12V
Clock 8.333333 MHz
8-bit ISA Bus 16-bit ISA Bus
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Typical buses – PCI Express Bus
Some focused information: PCI Express = Peripheral Component
Interconnect Express = PCI-E
PCI-E bus is an interconnect bus that allows you to add expansion boards to a computer.
PCI Express bus was developed in July 2002
It is the development of PCI -> it’s compatible with PCI architecture
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Typical buses – PCI Express Bus
Advantages of PCI Express High bandwidth, can reach up to 5-80 gigabits
per second.
The serial technology offers a scalable performance.
Point-to-point link for each device.
Small connectors facilitate the implementation for system designers.
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Typical buses – PCI Express Bus
PCI Express slots (x4,x16,x1,x16) and PCI slot
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Typical buses – USB Bus
Some focused information: USB = Universal Serial Bus
It based on serial type architecture
It is an input-output interface
It quicker than standard serial ports
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Typical buses – USB Bus
USB standards: The USB 1.0 standard developed from 1995 The USB 1.1 standards provide several
clarification but doesn’t change speed.
The USB 2.0 standard obtains speeds reach 480Mbit/s
The USB 3.0 standard released in 2007, the speed is 4.8 GB/s.
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Typical buses – USB Bus
Type of connectors: 2 Type A: the shape is rectangular and used for
less bandwidth intensive devices (keyboard, mouse, webcam, etc.)
Type B: the shape is square and used for high speed devices (external hard disks, etc.)
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Conclusion
Bus is very importance in computer architecture
It’s used largely and in most of everything which is related to physical computers
Use Bus to connect components in a processor.
There are 2 main parts in the bus system: system bus and I/O bus.
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Conclusion
We introduced some basic information about bus consists of concept, purposes of using, characteristics, advantages and disadvantages.
In the range of our research, we only mention some kinds of buses. They are address bus, data bus and control bus.
Some typical buses: ISA bus, PCI bus and USB bus.