Historical Background of Intel

Microprocessors
Intel 4004

Year of introduction 1971

 4-bit microprocessor
 4 KB main memory
 45 instructions
 PMOS technology
was first programmable device which was used in
calculators
Historical Background of Intel
Microprocessors
 Intel 8008

Year of introduction 1972

 8-bit version of 4004
 16 KB main memory
 48 instructions
 PMOS technology
 Slow
Historical Background of Intel
Microprocessors
 Intel 8080

Year of introduction 1973

 8-bit microprocessor
 64 KB main memory
 2 microseconds clock cycle time
 500,000 instructions/sec
 10X faster than 8008
 NMOS technology
 Drawback was that it needed three power supplies.
 Small computers (Microcomputers) were designed in mid 1970’s
using 8080 as CPU.
Historical Background of Intel
Microprocessors
 Intel 8085
 Year of introduction 1975
 8-bit microprocessor-upgraded version of 8080
 64 KB main memory
 1.3 microseconds clock cycle time
 246 instructions
 Intel sold 100 million copies of this 8-bit
microprocessor
 uses only one +5v power supply.
Historical Background of Intel
Microprocessors
 Intel 8086/8088

Year of introduction 1978 for 8086 and 1979 for 8088

 16-bit microprocessors
 Data bus width of 8086 is 16 bit and 8 bit for 8088
 1 MB main memory
 400 nanoseconds clock cycle time
 6 byte instruction cache for 8086 and 4 byte for 8088
 Other improvements included more registers and additional
instructions
 In 1981 IBM decided to use 8088 in its personal computer
Historical Background of Intel
Microprocessors
 Intel 80186

Year of introduction 1982

 16-bit microprocessor-upgraded version of 8086
 1 MB main memory
 Contained special hardware like programmable
counters, interrupt controller etc.
 Never used in the PC
 But was ideal for systems that required a minimum of
hardware
Historical Background of Intel
Microprocessors
 Intel 80286

Year of introduction 1983

 16-bit high performance microprocessor with memory
management & protection
 16 MB main memory
 Few additional instructions to handle extra 15 MB
 Instruction execution time is as little as 250 ns
 Concentrates on the features needed to implement
MULTITASKING
Historical Background of Intel
Microprocessors
 Intel 80386

Year of introduction 1986

 Intel’s first practical 32-bit microprocessor
 4 GB main memory
 Improvements include page handling in virtual
environment
 Includes hardware circuitry for memory management
and memory assignment
 Memory paging and enhanced I/O permissions
Historical Background of Intel
Microprocessors
 Intel 80486

Year of introduction 1989

 32-bit high performance microprocessor
 4 GB main memory
 Incorporates 80387-like floating point coprocessor and
 8 K byte cache on one package
 About half of the instructions executed in 1 clock
instead of 2 on the 80386
Historical Background of Intel
Microprocessors
 Pentium

Year of introduction 1993

 32-bit microprocessor, 64-bit data bus and 32-bit
address bus
 4 GB main memory
 Double clocked 120 and 133MHz versions
 Fastest version is the 233MHz, Dual integer processor
 16 KB L1 cache (split instruction and data: 8 KB each)
Historical Background of Intel
Microprocessors
 Pentium Pro

Year of introduction 1995

 32-bit microprocessor, formerly code-named P6
 64 GB main memory, 64-bit data bus and 36-bit
address bus
 16 KB L1 cache (split instruction/data: 8 KB each), 256
KB L2 cache
 Uses three execution engines
 Intel launched this processor for the server market
Historical Background of Intel
Microprocessors
 Pentium II

Year of introduction 1997

 32-bit microprocessor, 64-bit data bus and 36-bit
address bus, MMX
 64 GB main memory
 32 KB split instruction/data L1 caches (16 KB each)
 Module integrated 512KB L2 cache (133MHz)
 A version of P2 called Xeon; specifically designed for
high-end applications
Historical Background of Intel
Microprocessors
 Pentium III

Year of introduction 1999

 32-bit microprocessor, 64-bit data bus and 36-bit
address bus
 64 GB main memory
 Dual Independent Bus (simultaneous L2 and system
memory access)
 On-chip 256 KB L2 cache
 P3 was available in clock frequencies of up to 1 GHz
Historical Background of Intel
Microprocessors
 Pentium IV

Year of introduction 2002

 32-bit microprocessor, 64-bit data bus and 36-bit
address bus
 64 GB main memory
 1.4 to 1.9 GHz and the latest at 3.20 GHz and 3.46GHz
(Hyper-Threading)
 1MB/512KB/256KB L2 cache
 Specialized for streaming video, game and DVD
applications
Microprocessor
 is a semiconductor device consisting of
electronic logic circuits
 manufactured by using various fabrication
schemes
 capable of performing computing functions
 capable of transporting data/information
 can be divided into 3 segments:
 Arithmetic and Logic Unit
 Register Unit
 Control Unit
Von Neumann Machine
 Three key concepts:

 Data and instructions are stored in a single set of

read-write memory

 Contents of memory are addressable by memory

address, without regard to the type of data contained

 Execution occurs in a sequential fashion, unless

explicitly altered, from one instruction to the other
Computer System Components
 Memory

Stores instructions and data

 Input/Output
 Called peripherals
 Used to input and output instructions and data

 Arithmetic and Logic Unit

 – Performs arithmetic operations (addition, subtraction)
 – Performs logical operations (AND, OR, XOR,
SHIFT, ROTATE)
Computer System Components
 Control Unit
 – Coordinates the operation of the computer

System Interconnection and Interaction
 Bus—A group of lines used to transfer bits between the
microprocessor and other components of the computer
system. Bus is used to communicate between parts of the
computer. There is only one transmitter at a time and only
the addressed device can respond.

 Types
 » Address
 » Data
 » Control signals
CPU Components
Registers
 Hold data, instructions, or other items
 Various sizes
 Program counter and memory address registers
must be of same size/width as address bus
 Registers which hold data must be of same
size/width as memory words
CPU Components
Control Unit
 Generates control signals which are necessary
for execution of an instruction.
 Connect registers to the bus.
 Controls the data flow between CPU and
peripherals (including memory).
 Provides status, control & timing signals
required for the operation of memory and I/O
devices to the system.
 Acts as a brain of computer system
All actions of the control unit are associated
with the decoding and executions of
instructions (fetch and execute cycles).
CPU Components
Arithmetic and Logic Unit
 Executes arithmetic and logical operations.
 Accumulator is a special 8-bit register
associated with ALU.Register ‘A’ in 8085 is an
accumulator.
 Source of one of the operands of an arithmetic or
logical operation.
 serves as one input to ALU.
 Final result of an arithmetic or logical operation
is placed in accumulator.
Arithmetic and Logic Unit
ALU performs the following arithmetic & logical operations:
 Addition
 Subtraction
 Logical AND
 Logical OR
 Logical EXCLUSIVE OR
 Complement(logical NOT)
 Increment (add 1)
 Decrement (subtract 1)
 Left shift, Rotate Left, Rotate right
 Clear etc.
Status Flags
 Intel 8085 microprocessor contains five
flip-flops to serve as status flags. The
flip-flops are set or reset according to
the conditions which arise due to an
arithmetic & logical operation
ALU
PIN DIAGRAM 0F 8085