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Last Lecture
Logical Partitions of MS-DOS Disk
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Today's Lecture
Introduction to Intel 8086 microprocessor
Intel 8086 CPU Architecture
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Intel 8086 Microprocessor
Key Features:
Released by Intel in 1978
Produced from 1978 to 1990s
A 16-bit microprocessor chip.
Max. CPU clock rate :
5 MHz to 10 MHz
Instruction set: x86-16
Package: 40 pin DIP
The 8086 gave rise to Fig1:Intel 8086 Microprocessor
the x86 architecture of Intel's future processors.
Common manufacturer(s): Intel, AMD, NEC, Fujitsu, Harris
(Intersil), OKI, Siemens AG, Texas Instruments, Mitsubishi.
The Intel 8088, released in 1979, was a slightly modified
chip with an external 8-bit data bus and is notable as the
processor used in the original IBM PC.
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8086 CPU Chip
Fig1: 8086 CPU Chip in DIP Package Fig2: CPU Chip
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Intel 8086 architecture
The architecture was defined by Stephen P. Morse
with some help and assistance by Bruce Ravenel
(the architect of the 8087) in refining the final
revisions. Logic designer Jim McKevitt and John
Bayliss were the lead engineers of the hardware-level
development team and William Pohlman the
manager for the project.
The legacy of the 8086 is enduring in the basic
instruction set of today's personal computers and
servers; the 8086 also lent its last two digits to later
extended versions of the design, such as the Intel
286 and the Intel 386, all of which eventually became
known as the x86 family.
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Intel 8086 Process Technology
It was implemented using depletion-load nMOS
circuitry with approximately 20,000 active transistors
(29,000 counting all ROM and PLA sites).
It was soon moved to a new refined nMOS
manufacturing process called HMOS (for High
performance MOS) that Intel originally developed for
manufacturing of fast static RAM products.
This was followed by HMOS-II, HMOS-III versions,
and, eventually, a fully static CMOS version for
battery-powered devices, manufactured using Intel's
CHMOS processes.
The original chip measured 33 mm² (assume a
square of side length=0.57cm) and minimum feature
size was 3.2 μm.
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Why Choose the Intel 8086?
There is need to study a microprocessor. How it works, what is its
architecture, what is its instruction set architecture, how it is
programmed, how it is interfaced with other devices etc. etc.
8086 is first x86 microprocessor.
The term x86 refers to a family of instruction set architectures based
on the Intel 8086 CPU. The 8086 was launched in 1978 as a fully 16-
bit extension of Intel's early 8-bit based microprocessors and also
introduced segmentation to overcome the 16-bit addressing barrier of
earlier chips. The term x86 derived from the fact that early successors
to the 8086 also had names ending in "86". Many additions and
extensions have been added to the x86 instruction set over the years,
almost consistently with full backward compatibility.The architecture
has been implemented in processors from Intel, Cyrix, AMD, VIA, and
many others.
The PC market which uses Intel based devices takes up some 60% of
the total microprocessor market! The other main processor used by
industry is the Motorola 68000 family of microprocessors.
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Current x86 processors
http://en.wikipedia.org/wiki/8086
x86-32: EP80579 · Intel CE · Atom
x86-64: Atom (some) · Celeron ·
Pentium (Dual-Core) · Core (i3 · i5 · i7) · Xeon
Other: IOP · Itanium
x86 Assemblers: A86/A386 · FASM · GAS ·
HLA · MASM · NASM · TASM · WASM ·
YASM
http://en.wikipedia.org/wiki/X86_architecture
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8086 kit
Key features of this trainer kit are such as:
8086/8088 CPU operating at 2.5/5 MHz.
16 KB RAM with Battery backup expandable upto 256
KB.
16 KB powerful monitor EPROM.
24 I/O lines using 8255.
16 bit Timer/Counter using 8253.
RS-232C Interface using 8251.
8259 Interrupt Controller.
27 Series EPROM Programmer.
Printer Interface [Optional].
These kits are prepared and supplied by
many suppliers in India also for training and
education purpose.
Fig: 8086 kit
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http://www.flite.co.uk/the-flite-8086-an-introduction.htm
http://www.flite.co.uk/flite-flt-86-8086-training-system.htm
System Overview
The 8086 is probably the most commonly used 16-
bit microprocessor of all time, with the upwardly
compatible families of microprocessors developed
from it now at the heart of the virtually all personal
computers. This makes the 8086 the number one
choice as a platform for teaching microprocessor
principles on many computer science courses.
Fig2
Fig1: 8086 kit
The FLT86 is a well established training system for the 8086 CPU still being
manufactured by Flite Electronics International Limited in Southampton, England.
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8086 microprocessor
Address Bus – 20 lines – A19 – A0
Add
Bus
Data Bus – 16 lines – D15 – D0
Data
Microprocessor Bus
8086
16 bit- microprocessor ? Control
16-bits data bus? signals
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20 bits address bus?
It can address any one of A19……………A0
1,048,576 (=220
) memory 0……………….0 00000H
locations/addresses.
Each memory location is
one byte wide. 1……………….1 FFFFFH
To store a word of 16 bit 00000H
2 memory locations are
required.
If the first byte of the
word is at even address
8086 can read the entire
word in one operation. Memory
If the first byte of the Address
word is at an odd
address, the 8086 will Space
read the first byte with
one bus operation and
the second byte with
another bus operation.
1,048,576 memory locations=1MBytes FFFFFH
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8086 INTERNAL ARCHITECTURE
2 units are:
1. BIU
2. EU
Fig: 8086 Internal block diagram .
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BIU and EU
BIU (bus interface unit) sends out
addresses, fetches instructions from memory,
reads data from ports and memory, and
writes data to ports and memory. In other
words, the BIU handles all transfers of data
and addresses on the buses for the execution
unit.
EU (execution unit) of the 8086 tells the BIU
where to fetch instructions or data from,
decodes instructions, and executes
instructions.
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