PC Fundamentals
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Transcript PC Fundamentals
PC Fundamentals
Presentation 17 – Buses
Copyright © 2007 Heathkit Company, Inc. All Rights Reserved
Objectives
At the end of this presentation,
you will be able to:
2
Define computer bus and explain its
purpose.
Define the following terms: ISA, MCA,
EISA, VL-Bus, PCI, PCI Express, and AGP.
Discuss the characteristics of the PCI, PCI
Express, and AGP buses.
Recognize the connector (or slot) of an ISA,
PCI, PCI Express, and VGA bus.
3
CPU
Parallel Port
Memory
Keyboard Controller
Video
Adapter
The Data Bus
System Controller
4
CPU
Memory
Keyboard Controller
Video
Adapter
System Controller
5
CPU
Memory
Video
Adapter
6
7
What is a Bus?
Signal Pathways
A way of passing information between
components inside and outside the
computer.
A modular way of expanding the functions
or capabilities of the computer.
8
PC Bus Architectures
ISA
MCA
EISA
VL-Bus
PCI
AGP
PCI Express
9
The Original IBM PC Bus
Introduced on the original IBM PC
8-bit data path
4.77-MHz clock
8 Interrupts – Only one of which was
available for expansion boards.
4 DMA Channels – Only one of which was
available for expansion boards.
10
The Original IBM PC Bus
8-Bit Card
8-Bit Slot
11
Industry Standard Architecture
(ISA) Bus
Introduced
on the IBM AT Computer
16-bit data path
Backward compatible with IBM-PC Bus
8-MHz clock
15 Interrupts
7 DMA Channels
12
Industry Standard Architecture
(ISA) Bus
16-Bit Card
16-Bit Slot
8-Bit Section
Added Pins
13
Industry Standard Architecture
(ISA) Bus
8-Bit Card
16-Bit Slot
14
Micro-Channel Architecture (MCA)
Bus
Introduced on the IBM PS/2
16-bit or 32-bit data path
10-MHz clock
Configured by software rather than by
jumpers or switches
Not compatible with the ISA bus
Bus Mastering
15
Bus Mastering
Allows
data to be passed from one
device to another without CPU
intervention.
Allows
a controller card to take control
of the bus, leaving the CPU free to
concentrate on other tasks.
16
Bus Mastering vs. DMA
DMA can send data from peripheral to
RAM or from RAM to peripheral, without
the intervention of the CPU.
Bus Mastering can send data from
peripheral to peripheral, without the
intervention of the CPU.
17
Extended ISA Bus (EISA)
The industry’s answer to the MCA bus
Backward compatible with ISA
16-bit or 32-bit data path
8-MHz Clock
Configured by software, not jumpers or
switches
Bus Mastering
18
CPU
High Speed
CPU Bus
BUS
Controller
Low Speed
I/O Bus
ISA Bus
Slots
19
CPU
Local Bus
Slots
High Speed
CPU Bus
BUS
Controller
Low Speed
I/O Bus
ISA Bus
Slots
20
VESA Local Bus (VL-Bus)
Clock
speed same as the processor
32-bit
data path
Regular
ISA slot with local bus
connector added
Bus
Mastering
21
Peripheral Component Interconnect
(PCI)
Developed
for Pentium-class
processors
32-bit
and 64-bit data path versions
33-MHz
Clock
Processor
Plug
Independent
and Play with Bus Mastering
22
Peripheral Component Interconnect
(PCI) Bus
23
PCI Evolution
32-bit, 33 MHz
64-bit, 33 MHz
32-bit, 66 MHz
64-bit, 66 MHz
24
PCI-X
PCI-X 66
PCI-X 133
PCI-X 266
PCI-X 533
64-bit
64-bit
64-bit
64-bit
66 MHz
133 MHz
266 MHz
533 MHz
25
PCI Express
The
next generation of PCI.
Serial data paths.
Very high speed (2500 MHz)
Scales easily as additional serial data
paths are added.
X1 has one serial path, X4 four serial
paths, etc.
26
PCI-Express @ 2500 MHz
PCI Express x1
PCI Express x4
PCI Express x8
PCI Express x16
PCI Express x32
Lanes
Bandwidth
1
4
8
16
32
250 Mbps
1000 Mbps
2000 Mbps
4000 Mbps
8000 Mbps
27
PCI and PCI Express Slots
PCI Express X 16
PCI Express X 1
Conventional PCI
Conventional PCI
28
Accelerated Graphics Port (AGP)
Developed for high speed graphics cards
Frees the PCI bus from making video
transfers
Used only for video cards
Considered a port rather than a bus
66 MHz, 32-Bit
29
Accelerated Graphics Port
(AGP)
30
AGP Modes
32-bits @ 66 MHz
Data Cycles
Per Clock
AGP
AGP 2X
AGP 4X
AGP 8X
1
2
4
8
Bandwidth
266 Mbps
533 Mbps
1066 Mbps
2133 Mbps
31
PC Fundamentals
End
Copyright © 2007 Heathkit Company, Inc. All Rights Reserved