Introduction

• Buses carry signal between the components.

• A bus is a common pathway in which data can

travel within a computer.

• This pathway used for communication and can be

established between elements

Different types of Bus1. ISA - Industry Standard

Architecture

2. EISA - Extended ISA

3. VESA - Video Electronics Standards

Association, VL Bus

4. PCI - Peripheral Component

Interconnect

5. USB - Universal Serial Bus

6. AGP - Advanced Graphics Port

ISA Bus

• ISA stands for Industry Standard

Architecture. It was a computer bus standard

for IBM compatible computers.

• ISA is the basics foAr Modern Personal

Computer. Based on the number of bits

that can be transferred on the bus.

ISA Bus Architecture

There are two versions of ISA bus.

• 8 bit ISA bus

• 16 bit ISA bus

8 bit ISA Bus

• The speed of 8 bit ISA is 4.77 MHz

• The Maximum bandwidth of 8 bit ISA bus is 4.17

MB/sec

• The bus slot provides 8 data lines and 20 address

lines

8 bit ISA Bus

16bit ISA Bus

• The 16 bit ISA bus Man at a speed of 8 MHz

• The maximum bandwidth by the 16bit ISA Bus is

8.33 MB/sec

• The 16 bit ISA bus adding an optional 16 bit

extension connector

16bit ISA Bus

EISA Bus

• The Extended Industry Standard Architecture is a

bus standard for IBM compatible computers.

• EISA buses are 32 bits wide

and support multiprocessing.

EISA Bus Architecture

VESA Bus • The VESA Local Bus (usually abbreviated to VL-

Bus or VLB) was mostly used in personal computers. 

• VESA (Video Electronics Standards Association)

Local Bus worked alongside the ISA bus.

• It acted as a high-speed conduit for memory-mapped

I/O and DMA, while the ISA bus handled interrupts

and port-mapped I/O.

VESA Bus

PCI Bus

• The PCI (Peripheral Component Interconnect) is a

high performance Bus for interconnecting chips,

expansion boards, and memory cards.

• It was originated at Intel Inc. In the early 1990’s as

standard methods of interconnecting chips on a

board. 

• Information typically transferred across the PCI bus at

33 MHz and 32 bit at a time.

• The bandwidth is calculated from the following

formula.

3.33 MHz x 4 bytes (32 bits) = 133 MB/sec.

3.33 MHz x 4 bytes (32 bits) = 133 MB/sec.

PCI Bus Architecture

Bus slots

USB Bus

• Universal Serial Bus (USB) is a specification to

establish communication between devices and a host

controller.

• USB was designed for personal computers, but it has

become commonplace on other devices such as smart

phones, PDAs and video game consoles, and as a power

cord.

USB Bus

USB Bus interface

Important Signals

Pin Name Cable Color Description

1 VCC Red +5 VDC

2 D- White Data -

3 D + Green Data +

4 GND Black Ground

The End

……Thank you……