What is cpu?
• The function of any computer revolves
around a central component known as CPU.
• CPU known as the “Central Processing
unit” is called the “BRAIN OF THE
• CPU is responsible for processing the data
inside the computer system.It is also
responsible for controlling all other
components of the system.
The central processing unit (CPU) of a
computer is the main unit that dictates
the rest of the computer organization
1. Register set: Stores intermediate data
during the execution of instructions;
2. Arithmetic logic unit (ALU):Performs
the required micro-operations for
executing the instructions
3. Control unit: supervises the transfer of
information among the registers and
instructs the ALU as to which operation to
perform by generating control signals.
Simple Model Computer block diagram
Arithmetic and logic unit
1 Arithmetic and Logical
operations are performed in
2 ALU consists of an
accumulator (ACC), a set of
logic circuits, and a
status register (SR).
1 Control Unit
controls the overall
operations of the
Control Unit Consists
of the program
Counter (PC), the
instruction register (IR)
and the instruction
Memory Unit 1
Memory unit consists of
the main store, the
memory data register
(MDR), the memory
address register (MAR),
and the address decoder.
Main store is composed of
a large number of memory
• The law is named after Intel co-founder
• It is the observation that “over the history of
computing hardware, the number of
transistors on integrated circuits double
approximately every two years”.
• The Period is often quoted as “6 months”.
• The law is now used in the SemiConductor industry to guide long-term planning
and to set targets for research &
It`s a multipurpose, programmable device that accepts digital
data as input, processes it according to instructions stored in its
memory & provides results as output.
Microprocessors operate on numbers and symbols.
General-purpose microprocessors in personal computers are
used for computation, text editing, multimedia display, and
communication over the Internet.
Many more microprocessors are part of embedded systems,
providing digital control of a myriad of objects from appliances
to automobiles to cellular phones and industrial process
On the basis of instruction set, these`re classified into CISC &
chip maker."Intel Inside" advertising
campaign made it and its Pentium
processor household names..
Founded by Robert Noyce, Gordan
Moore, Andrew in 1968.
Celeron is a brand name given by
Intel Corp. to a number of different x86
computer microprocessor models.
Introduced in April 1988.
Advanced Micro Devices, Inc.(AMD
)`s an American multinational
semiconductor company based in
Sunnyvale, California. main products
include microprocessors, motherboard
Athlon is the brand name applied to a
series of x86-compatible
microprocessors designed and
manufactured by Advanced Micro
The Athlon made its debut on June 23,
1999. Athlon is the ancient Greek word
for "Champion/trophy of the games"
The Motorola 68000 is a 16/32-bit CISC
microprocessor core designed and
marketed by Freescale Semiconductor
(formerly Motorola Semiconductor
Introduced in 1979.
THE 8 BIT
THE 16 BIT
THE 32 BIT
THE 64 BIT PROCESSORS
INTEL CORE 2
INTEL CORE i3
INTEL CORE i5
INTEL CORE i7
4 BIT MICROPROCESSORS
Year of Introduction
to 740 kHz
500 kHz to
8 BIT MICROPROCESSORS
16 BIT MICROPROCESSORS
From 1979 to
transistor ons per
16 BIT MICROPROCESSORS
Year of Clock rate
transistors per second
6 MHz with
8 MHz, 10
32 BIT MICROPROCESSORS
Transistor per second
64 BIT MICROPROCESSORS
Name & Yr of Intro
No. of cores
Intel Core 2 (2006)
Clock speed: 1.2
GHz to 3 GHz.
291 million transistors..
Launched in three
Intel Core 2 Duo
Intel Core 2 Quad
Intel Core 2 Extreme
Intel Core i3
2 Physical Cores
clock speed: 2.93
GHz to 3.33 GHz
Intel Core i5
4 Physical Cores
Clock speed: 2.40
GHz to 3.60 GHz.
781 million transistors.
Intel Core i7 (2008)
4 Physical Cores
Clock rate: 2.66
GHz to 3.33 GHz.
CPU SPEED (MHz)
PENTIUM II/ XEON
16 BIT SUCCESSOR TO
16 MB, LINEAR
FIRST WITH 32 BIT
FREQUENTLY USED TERMS:
CLOCK RATE:Typically refers to the frequency at which
a CPU is running. It uses the SI unit Hertz.
TRANSISTOR: A transistor is a semiconductor device
used to amplify and switch electronic signals and
electrical power. The transistor is the fundamental
building block of modern electronic devices, and is
ubiquitous in modern electronic systems.
BIT:It`s the basic unit of a memory.
• CACHE MEMORY: High speed memory present b/w RAM
& CPU. Inc. the processing speed.
• MULTI CORE PROCESSING:A multi-core processor is a
single computing component with two or more
independent actual central processing units (called
"cores"), which are the units that read and execute
• THERMAL DESIGN POWER: The thermal design power
(TDP), refers to the maximum amount of power the
cooling system in a computer is required to dissipate.
• DATA BUS: In computer architecture, a bus is a
subsystem that transfers data between CPU & Memory,
• CONTROL BUS: Specifies whether the data`s to be read
or written to the memory.
• ADDRESS BUS: An address bus is a computer bus (a
series of lines connecting two or more devices) used to
specify a physical address.
CISC VS RISC
1. Complex Instruction Set
Computer (CISC) processors
has a bigger instruction set with
many addressing modes.
1.Reduced Instruction Set Computers
(RISC) processors have a smaller
instruction set with few addressing
2. It has to use a separate microprogramming unit with a control
memory to implement complex
2.It has a hard-wired programmedunit without a control memory, and
separate hardware to implement each
and every instruction.
3. An easy compiler design
3. A complex compiler design.
4. The calculations are slower and 4The calculations are faster and precise
instruction 5. Decoding of instruction is simple
6.The Execution time is very high.
6. It takes very less execution time.
7. They frequently need the external 7. Since they use a hardwired model,
memory access to make calculations.
they take the external memory access for
8. Pipelining does not function correctly 8. Pipelining is not a major problem and
in this option speeds up the processors.
9. These processors often stall because of 9. Since the instructions are
complex, stalling is mostly reduced.
10. Code Expansion is not a problem in 10. Code expansion can be a problem in
some cases for RISC processors.
11. Disc space is wasted.
11. Disc space is saved.
12. Used in low end applications such us 12. Used in High end applications such us
Security systems, home automation
video processing, telecommunications,
APPLICATIONS OF A MICROPROCESSOR
Instrumentation: Frequency counters, function generators, frequency synthesizers, spectrum
analyses and many other instruments are available , where microprocessors are used as
controller. Also used in medical instrumentation.
Microprocessor based controllers are available in home appliances, such as microwave oven,
washing machine etc.
Digital telephone sets. The use of microprocessor in television, satellite communication have
made teleconferencing possible. Railway reservation and air reservation system also uses this
technology. LAN and WAN for communication of vertical information through computer network.
Office Automation and Publication :
Microprocessors based systems are being used for word processing, spread sheet operations,
Consumer : The use of microprocessor in toys, entertainment equipment and home applications
is making them more entertaining and full of features.
BENEFITS & LIMITATIONS
• BENEFITS: Microprocessors make quick
decisions and handle multiple
instructions based on those quick
• LIMITATIONS: Sometimes, they get
over-heated, and restriction inflicts on
size of data.
What features should one consider about
the processor while purchasing a
a) The clock speed of the processor. The more the
speed, the faster`s the processor.
b) The bus speed. High bus speeds will increase the
performance of computer operations that are RAMintensive, such as video and audio editing and
coding programs, or high-end 3D games.
c) Number of "Cores". More cores, faster CPU.
d) Cache memory of the CPU. The more it is, the
faster`s the computer.