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CHAPTER I
Problem and its Background
Introduction
The part of the text is designed to introduce you to some of the
more popular microprocessors. The design and operation of a
microprocessor are based on the digital circuits which you studied.
You will learn the basic principles of microprocessors and how to write
simple assembly language programs. In the study of computer,
programming, and microprocessor one fundamental idea emerges.
If you understand the basic principles and simple programs presented
here, you will depend on your way to understanding more complicated
ideas.
Since the microprocessor is a “computer on a chip,” it may help to
take a quick look at computer before starting to study
microprocessors.8085 it was the most popular microprocessor of the early
70’s, It had several disadvantage such as needing two power supplies
plus externally generated clock and control signal. In the other words the
8080 in not cpu on a chip because the clock and controller are on
separate.
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The 8085 microprocessor they are two types block diagram and pin
configuration,. block diagram show the control signal drive all the internet
register first is called address, data, and control buses on the internet the
diagram is an 8 bit internal data bus. This is the CPU register.
Accumulator is connected to the 8-bit internal data bus.
The pin configuration is a part of microprocessor of 8085 is not a
same block diagram but is a microprocessor because the system you
need a general idea of what each pin owes, from pin 1 to pin 40.
A microprocessor it also known as a CPU or central processing unit is a
complete computation engine that is fabricated on a single chip. If you have ever
wondered what the microprocessor in your computer is doing, or if you have ever
wondered about the differences between types of microprocessors, then read on.
In this article, you will learn how fairly simple digital logic techniques allow a
computer to do its job, whether it’s playing a game or spell checking a document.
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Objectives of the study
After completing this chapter, you should be able to:
1) List the three main units of stored-program computer
2) Identify the function of the address, data, and control buses in a stored-
program computer.
3) Trace the evolution of the computer from the vacuum tube machine to
the microprocessor.
4) Identify significant computer that have been built over the years.
Statement of the Problem
How Microprocessor Works
The computer you are using to read this page uses a microprocessor to do
its work. The microprocessor is the heart of any normal computer, whether it is a
desktop machine, a server or a laptop. The microprocessor you are using might be
a Pentium, a K6, a PowerPC, a Sparc or any of the many other brands and types
of microprocessors, but they all do approximately the same thing in
approximately the same way.
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A microprocessor -- also known as a CPU or central processing unit -- is a
complete computation engine that is fabricated on a single chip. The first
microprocessor was the Intel 4004, introduced in 1971. The 4004 was not very
powerful -- all it could do was add and subtract, and it could only do that 4 bits at
a time. But it was amazing that everything was on one chip. Prior to the 4004,
engineers built computers either from collections of chips or from discrete
components (transistors wired one at a time). The 4004 powered one of the first
portable electronic calculators.
If you have ever wondered what the microprocessor in your computer is
doing, or if you have ever wondered about the differences between types of
microprocessors, then read on. In this article, you will learn how fairly simple
digital logic techniques allow a computer to do its job, whether it’s playing a
game or spell checking a document.
Features
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Microprocessors have become the movers and shakers of our everyday world.
We use them in computers, televisions, watches, microwaves and practically
every other electronic device. Their micro-size is no reflection of the myriad
capabilities these chips possess, ranging from 2 to 3 mm square to maybe an inch
thick. Silicon makes up the material of a microprocessor chip. Sliced wafer thin,
silicon serves as an ideal conductor and insulator for transmitting electrical
currents throughout the components of the chip. The finished product is an
integrated circuit composed of layers of built-in wiring and transistors. Through
the use of laser light, circuit outlines are etched onto a silicon surface through a
mask or stencil design. A simple chip can have as many as 3,000 transistors, with
as narrow a spacing of 60 nanometers between each one.
Function
Figure 1.0
Microchip
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A microprocessor is the central processing unit in a computer. It receives,
transmits and coordinates every command and process carried out by the system.
Electrical currents, moving through wires and transistors, are converted into
usable messages through the use of a Boolean logic language. Based on the
"on/off" frequency of current moving through transistor circuits, this Boolean
logic communicates system commands to and from receiving devices within the
computer. The microprocessor communicates within two primary capacities: logic
and the processing of information. These processes are handled by two
components within the chip: *Arithmetic logic unit (ALU), responsible for all
commands requiring an arithmetic or logic function *Control unit (CU), which
handles the information processing from the computer's memory.
Figure 1.1
Potential
1. From these units within the chip, clusters of wires called "bus" lines send
and receive information to and from system devices.
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2. The first microprocessor chip was designed in 1974. Since that time,
technological advancements continue to reduce the size requirements of
chips while doubling their processing capability. This continued progress
has made for a more efficient unit, and material costs have gone down
considerably.
3. The next step toward further development lies within the field of
nanotechnology. This field works within the molecular/subatomic realm of
science. Its purpose is to rebuild the most basic of materials--atoms and
molecules--from the ground up. Currently, nanotechnologists are working
to replicate the microprocessor chip model on a molecular scale. Once
completed, information-processing capabilities will dwarf our current
processing abilities. These improvements are expected to radically alter
technology as we know it today.
How bits and bytes work?
If you have used a computer for more than five minutes, then you have
heard the words bits and bytes. Both RAM and hard disk capacities are measured
in bytes. So are file sizes when you examine them in a file viewer. For example,
you might hear an advertisement that says "This computer has a 32-bit Pentium
processor with 64 megabytes of RAM and 2.1 gigabytes of hard disk space."
Decimal number
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The easiest way to understand bits is to compare them to something you
know: digits. A digit is a single place that can hold numerical values between 0
and 9. Digits are normally combined together in groups to create larger numbers.
For example, 6357 has 4 digits. It is understood that in the number 6357 that the 7
is filling the "1s place", while the 5 is filling the 10s place, the 3 is filling the 100s
place and the 6 is filling the 1000s place. So you could express things this way if
you wanted to be explicit:
(6 * 1000) + (3 * 100) + (5 * 10) + (7 * 1) = 6000 + 300 + 50 + 7 =
6357
Another way to express it would be to use powers of 10. Assuming that we are
going to represent the concept of "raised to the power of" with the "^" symbol (so
"10 squared" is written as "10^2"), another way to express it is like this:
(6 * 10^3) + (3 * 10^2) + (5 * 10^1) + (7 * 10^0) = 6000 + 300 +
50 + 7 = 6357
What you can see from this expression is that each digit is a placeholder for the
next higher power of 10, starting in the first digit with 10 raised to the power of
zero.
That should all feel comfortable - we all work with decimal digits every day and
have no problems. The neat thing about number systems is that there is nothing
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that forces you to have 10 different values in a digit. Our "base-10" number
system likely grew up because we have 10 fingers, but if we happened to evolve
to have 8 fingers instead we would probably have a base-8 number system. You
can have base-anything numbers systems. In fact, there are lots of good reasons to
use different bases in different situations.
Bits
Computers happen to operate using the base-2 number system, also known
as the binary number system (just like the base-10 number system is known as
the decimal number system). The reason computers use the base-2 system is
because it makes it a lot easier to implement them with current electronic
technology. You could wire up and build computers that operate in base-10, but
they would be fiendishly expensive right now. On the other hand, base-2
computers are dirt cheap.
So computers use binary numbers, and therefore use binary digits in place
of decimal digits. The word bit is a shortening of the words "Binary digIT".
Where decimal digits have 10 possible values ranging from 0 to 9, bits have only
2 possible values: 0 and 1. Therefore a binary number is composed of only 0s and
1s, like this: 1011. How do you figure out what the value of the binary number
1011 is? You do it in the same way we did it above for 6357, but you use a base
of 2 instead of a base of 10. So:
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(1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0) = 8 + 0 + 2 + 1 = 11
You can see that in binary numbers, each bit holds the value of increasing
powers of 2. That makes counting in binary pretty easy. Starting at zero and going
though 20, counting in decimal and binary look like this
0 = 0
1 = 1
2 = 10
3 = 11
4 = 100
5 = 101
6 = 110
7 = 111
8 = 1000
9 = 1001
10 = 1010
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11 = 1011
12 = 1100
13 = 1101
14 = 1110
15 = 1111
16 = 10000
17 = 10001
18 = 10010
19 = 10011
20 = 10100
When you look at this sequence, 0 and 1 are the same for decimal and
binary number systems. At the number 2 you see carrying first take place in the
binary system. If a bit is 1, and you add 1 to it, the bit becomes zero and the next
bit becomes 1. In the transition from 15 to 16 this effect roles over through 4 bits,
turning 1111 into 10000.
Bytes
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Bits are rarely seen alone in computers. They are almost always bundled
together into 8-bit collections, and these collections are called bytes. Why are
there 8 bits in a byte? A similar question is, "Why are there 12 eggs in a dozen?"
The 8-bit byte is something that people settled on through trial and error over the
past 50 years.
With 8 bits in a byte, you can represent 256 values ranging from 0 to 255, as
shown here:
0 = 00000000
1 = 00000001
2 = 00000010
...
254 = 11111110
255 = 11111111
In the How Stuff Works article on CDs you saw that a CD uses 2 bytes, or 16
bits, per sample. That gives each sample a range from 0 to 65,535, like this:
0 = 0000000000000000
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1 = 0000000000000001
2 = 0000000000000010
...
65534 = 1111111111111110
65535 = 1111111111111111
Bytes are frequently used to hold individual characters in a text document.
In the ASCII character set, each binary value between 0 and 127 is given a
specific character. Most computers extend the ASCII character set to use the full
range of 256 characters available in a byte. The upper 128 characters handle
special things like accented characters from common foreign languages.
The table at the right shows the 127 standard ASCII codes. Computers
store text documents, both on disk and in memory, using these codes. For
example, if you use Notepad in Windows 95/98 to create a text file containing the
words, "Four score and seven years ago", Notepad would use one byte of memory
per character (including one byte for each space character between the words
(ASCII value 32)). When Notepad stores the sentence in a file on disk, the file
will also contain one byte per character and space. Try this experiment: open up a
new file in Notepad and insert the sentence, "Four score and seven years ago" in
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it. Save the file to disk under the name getty.txt. Then use the explorer and look
at the size of the file. You will find that the file has a size of 30 bytes on disk: one
byte for each character. If you add another word to the end of the sentence and re-
save it, the file size will jump to the appropriate number of bytes. Each character
consumes a byte.
If you were to look at the file as a computer looks at it, you would find
that each byte contains not a letter but a number. The number is the ASCII code
corresponding to the character. So on disk The numbers for the file look like this:
F o u r a n d s e v e n ...
70 111 117 114 32 97 110 100 32 115 101 118 101 110 32 ...
By looking in the ASCII table you can see a one-to-one correspondence
between each character and the ASCII code used. Note the use of 32 for a space -
32 is the right ASCII code for a space. We could expand these decimal numbers
out to binary numbers (so 32 = 00100000) if we wanted to be technically correct -
that is how the computer really deals with things.
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How Boolean Logic Work
Figure 1.2
A solder less breadboard
In the article How Boolean Logic Works, we looked at seven fundamental
gates. These gates are the building blocks of all digital devices. We also saw how
to combine these gates together into higher-level functions, such as full adders. If
you would like to experiment with these gates so you can try things out yourself,
the easiest way to do it is to purchase something called TTL chips and quickly
wire circuits together on a device called a solder less breadboard. Let's talk a
little bit about the technology and the process so you can actually try it out!
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If you look back at the history of computer technology, you find that all
computers are designed around Boolean gates. The technologies used to
implement those gates, however, have changed dramatically over the years. The
very first electronic gates were created using relays. These gates were slow and
bulky. Vacuum tubes replaced relays. Tubes were much faster but they were just
as bulky, and they were also plagued by the problem that tubes burn out (like light
bulbs). Once transistors were perfected (transistors were invented in 1947),
computers started using gates made from discrete transistors. Transistors had
many advantages: high reliability, low power consumption and small size
compared to tubes or relays. These transistors were discrete devices, meaning that
each transistor was a separate device. Each one came in a little metal can about
the size of a pea with three wires attached to it. It might take three or four
transistors and several resistors and diodes to create a gate.
In the early 1960s, integrated circuits (ICs) were invented. Transistors,
resistors and diodes could be manufactured together on silicon "chips." This
discovery gave rise to SSI (small scale integration) ICs. An SSI IC typically
consists of a 3-mm-square chip of silicon on which perhaps 20 transistors and
various other components have been etched. A typical chip might contain four or
six individual gates. These chips shrank the size of computers by a factor of about
100 and made them much easier to build.
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As chip manufacturing techniques improved, more and more transistors
could be etched onto a single chip. This led to MSI (medium scale integration)
chips containing simple components, such as full adders, made up of multiple
gates. Then LSI (large scale integration) allowed designers to fit all of the
components of a simple microprocessor onto a single chip. The 8080 processor,
released by Intel in 1974, was the first commercially successful single-chip
microprocessor. It was an LSI chip that contained 4,800 transistors. VLSI (very
large scale integration) has steadily increased the number of transistors ever since.
The first Pentium processor was released in 1993 with 3.2 million transistors, and
current chips can contain up to 20 million transistors.
In order to experiment with gates, we are going to go back in time a bit
and use SSI ICs. These chips are still widely available and are extremely reliable
and inexpensive. You can build anything you want with them, one gate at a time.
The specific ICs we will use are of a family called TTL (Transistor Logic, named
for the specific wiring of gates on the IC). The chips we will use are from the
most common TTL series, called the 7400 series. There are perhaps 100 different
SSI and MSI chips in the series, ranging from simple AND gates up to complete
ALUs (arithmetic logic units).
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Figure 1.3
Integrated circuit
The 7400-series chips are housed in DIPs (dual inline packages). As
pictured on the right, a DIP is a small plastic package with 14, 16, 20 or 24 little
metal leads protruding from it to provide connections to the gates inside. The
easiest way to construct something from these gates is to place the chips on a
solder less breadboard. The breadboard lets you wire things together simply by
plugging pieces of wire into connection holes on the board.
All electronic gates need a source of electrical power. TTL gates use 5
volts for operation. The chips are fairly particular about this voltage, so we will
want to use a clean, regulated 5-volt power supply whenever working with TTL
chips. Certain other chip families, such as the 4000 series of CMOS chips, are far
less particular about the voltages they use. CMOS chips have the additional
advantage that they use much less power. However, they are very sensitive to
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static electricity, and that makes them less reliable unless you have a static-free
environment to work in. Therefore, we will stick with TTL here.
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CHAPTER II
Conceptual Framework
Microprocessor History
Figure 1.3
Various microprocessors
A microprocessor (sometimes abbreviated µP) is a digital electronic
component with transistors on a single semiconductor integrated circuit (IC). One
or more microprocessors typically serve as a central processing unit (CPU) in a
computer system or handheld device.
Microprocessors made possible the advent of the microcomputer. Before
this, electronic CPUs were typically made from bulky discrete switching devices
(and later small-scale integrated circuits) containing the equivalent of only a few
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transistors. By integrating the processor onto one or a very few large-scale
integrated circuit packages (containing the equivalent of thousands or millions of
discrete transistors), the cost of processor power was greatly reduced. Since the
advent of the IC in the mid-1970s, the microprocessor has become the most
prevalent implementation of the CPU, nearly completely replacing all other
forms.
The evolution of microprocessors has been known to follow Moore's Law when it
comes to steadily increasing performance over the years. This law suggests that
the complexity of an integrated circuit, with respect to minimum component cost,
doubles every 24 months. This dictum has generally proven true since the early
1970s. From their humble beginnings as the drivers for calculators, the continued
increase in power has led to the dominance of microprocessors over every other
form of computer; every system from the largest mainframes to the smallest
handheld computers now uses a microprocessor at its core.
The first microprocessors
As with many advances in technology, the microprocessor was an idea
whose time had come. Three projects arguably delivered a complete
microprocessor at about the same time, Intel's 4004, Texas Instruments' TMS
1000, and Garrett Air search’s Central Air Data Computer.
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In 1968, Garrett was invited to produce a digital computer to compete with
electromechanical systems then under development for the main flight control
computer in the US Navy's new F-14 Tomcat fighter. The design was complete by
1970, and used a MOS-based chipset as the core CPU. The design was smaller
and much more reliable than the mechanical systems it competed against, and was
used in all of the early Tomcat models. However, the system was considered so
advanced that the Navy refused to allow publication of the design, and continued
to refuse until 1997. For this reason the CADC, and the MP944 chipset it used,
are fairly unknown even today.
TI developed the 4-bit TMS 1000 and stressed pre-programmed embedded
applications, introducing a version called the TMS1802NC on September 17,
1971, which implemented a calculator on a chip. The Intel chip was the 4-bit
4004, released on November 15, 1971, developed by Federico Faggin.
TI filed for the patent on the microprocessor. Gary Boone was awarded U.S.
Patent 3,757,306 for the single-chip microprocessor architecture on September 4,
1973. It may never be known which company actually had the first working
microprocessor running on the lab bench. In both 1971 and 1976, Intel and TI
entered into broad patent cross-licensing agreements, with Intel paying royalties
to TI for the microprocessor patent. A nice history of these events is contained in
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court documentation from a legal dispute between Cyrix and Intel, with TI as
intervener and owner of the microprocessor patent.
A computer-on-a-chip is a variation of a microprocessor which combines
the microprocessor core (CPU), some memory, and I/O (input/output) lines, all on
one chip. The computer-on-a-chip patent, called the "microcomputer patent" at
the time, U.S. Patent 4,074,351, was awarded to Gary Boone and Michael J.
Cochran of TI. Aside from this patent, the standard meaning of microcomputer is
a computer using one or more microprocessors as its CPU(s), while the concept
defined in the patent is perhaps more akin to a microcontroller.
According to A History of Modern Computing, (MIT Press), pp. 220-21,
Intel entered into a contract with Computer Terminals Corporation, later called
Data point, of San Antonio TX, for a chip for a terminal they were designing.
Data point later decided not to use the chip, and Intel marketed it as the 8008 in
April, 1972. This was the world's first 8-bit microprocessor. It was the basis for
the famous "Mark-8" computer kit advertised in the magazine Radio-Electronics
in 1974. The 8008 and its successor, the world-famous 8080, opened up the
microprocessor component marketplace.
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Notable 8-bit designs
The 4004 was later followed in 1972 by the 8008, the world's first 8-bit
microprocessor. These processors are the precursors to the very successful Intel
8080 (1974), Zilog Z80 (1976), and derivative Intel 8-bit processors. The
competing Motorola 6800 was released in August 1974. Its architecture was
cloned and improved in the MOS Technology 6502 in 1975, rivaling the Z80 in
popularity during the 1980s.
Both the Z80 and 6502 concentrated on low overall cost, through a
combination of small packaging, simple computer bus requirements, and the
inclusion of circuitry that would normally have to be provided in a separate chip
(for instance, the Z80 included a memory controller). It was these features that
allowed the home computer "revolution" to take off in the early 1980s, eventually
delivering semi-usable machines that sold for US$99.
The Western Design Center, Inc. (WDC) introduced the CMOS 65C02 in
1982 and licensed the design to several companies which became the core of the
Apple IIc and IIe personal computers, medical implantable grade pacemakers and
defibrillators, automotive, industrial and consumer devices. WDC pioneered the
licensing of microprocessor technology which was later followed by ARM and
other microprocessor Intellectual Property (IP) providers in the 1990s.
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Motorola trumped the entire 8-bit world by introducing the MC6809 in 1978,
arguably one of the most powerful, orthogonal, and clean 8-bit microprocessor
designs ever fielded - and also one of the most complex hardwired logic designs
that ever made it into production for any microprocessor. Micro coding replaced
hardwired logic at about this point in time for all designs more powerful than the
MC6809 - specifically because the design requirements were getting too complex
for hardwired logic.
Another early 8-bit microprocessor was the Signe tics 2650, which
enjoyed a brief flurry of interest due to its innovative and powerful instruction set
architecture.
A seminal microprocessor in the world of spaceflight was RCA's RCA
1802 (aka CDP1802, RCA COSMAC) (introduced in 1976) which was used in
NASA's Voyager and Viking space probes of the 1970s, and onboard the Galileo
probe to Jupiter (launched 1989, arrived 1995). RCA COSMAC was the first to
implement C-MOS technology. The CDP1802 was used because it could be run at
very low power, and because its production process (Silicon on Sapphire) ensured
much better protection against cosmic radiation and electrostatic discharges than
that of any other processor of the era. Thus, the 1802 is said to be the first
radiation-hardened microprocessor.
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16-bit designs
The first multi-chip 16-bit microprocessor was the National
Semiconductor IMP-16, introduced in early 1973. An 8-bit version of the chipset
was introduced in 1974 as the IMP-8. In 1975, National introduced the first 16-bit
single-chip microprocessor, the PACE, which was later followed by an NMOS
version, the INS8900.
Other early multi-chip 16-bit microprocessors include one used by Digital
Equipment Corporation (DEC) in the LSI-11 OEM board set and the packaged
PDP 11/03 minicomputer, and the Fairchild Semiconductor Micro Flame 9440,
both of which were introduced in the 1975 to 1976 timeframe.
The first single-chip 16-bit microprocessor was TI's TMS 9900, which
was also compatible with their TI 990 line of minicomputers. The 9900 was used
in the TI 990/4 minicomputer, the TI-99/4A home computer, and the TM990 line
of OEM microcomputer boards. The chip was packaged in a large ceramic 64-pin
DIP package while most 8-bit microprocessors such as the Intel 8080 used the
more common, smaller, and less expensive plastic 40-pin DIP. A follow-on chip,
the TMS 9980, was designed to compete with the Intel 8080, had the full TI 990
16-bit instruction set, used a plastic 40-pin package, moved data 8 bits at a time,
but could only address 16KB. A third chip, the TMS 9995, was a new design. The
family later expanded to include the 99105 and 99110.
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The Western Design Center, Inc. (WDC) introduced the CMOS 65816 16-
bit upgrade of the WDC CMOS 65C02 in 1984. The 65816 16-bit microprocessor
was the core of the Apple IIgs and later the Super Nintendo Entertainment
System, making it one of the most popular 16-bit designs of all time.
Intel followed a different path, having no minicomputers to emulate, and
instead "upsized" their 8080 design into the 16-bit Intel 8086, the first member of
the x86 family which powers most modern PC type computers. Intel introduced
the 8086 as a cost effective way of porting software from the 8080 lines, and
succeeded in winning a lot of business on that premise. The 8088, a version of the
8086 that used an external 8-bit data bus, was the microprocessor in the first IBM
PC, the model 5150. Following up their 8086 and 8088, Intel released the 80186,
80286 and, in 1985, the 32-bit 80386, cementing their PC market dominance with
the processor family's backwards compatibility.
The integrated microprocessor memory management unit (MMU) was
developed by Childs et al. of Intel, and awarded US patent number 4,442,484.
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Figure 1.4
Upper interconnect layers on an Intel 80486 DX2
16-bit designs were in the market only briefly when full 32-bit
implementations started to appear.
The world's first single-chip 32-bit microprocessor was the AT&T Bell
Labs BELLMAC-32A, with first samples in 1980, and general production in
1982. After the divestiture of AT&T in 1984, it was renamed the WE 32000
(WE for Western Electric), and had two follow-on generations, the WE 32100 and
WE 32200. These microprocessors were used in the AT&T 3B5 and 3B15
minicomputers; in the 3B2, the world's first desktop super microcomputer; in the
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"Companion", the world's first 32-bit laptop computer; and in "Alexander", the
world's first book-sized super microcomputer, featuring ROM-pack memory
cartridges similar to today's gaming consoles. All these systems ran the original
Bell Labs Unix Operating System, which included the first Windows-type
software called xt-layers.
The most famous of the 32-bit designs is the MC68000, introduced in
1979. The 68K, as it was widely known, had 32-bit registers but used 16-bit
internal data paths, and a 16-bit external data bus to reduce pin count. Motorola
generally described it as a 16-bit processor, though it clearly has 32-bit
architecture. The combination of high speed, large (16 megabyte) memory space
and fairly low costs made it the most popular CPU design of its class. The Apple
Lisa and Macintosh designs made use of the 68000, as did a host of other designs
in the mid-1980s, including the Atari ST and Commodore Amiga.
Intel's first 32-bit microprocessor was the iAPX 432, which was
introduced in 1981 but was not a commercial success. It had an advanced
capability-based object-oriented architecture, but poor performance compared to
other competing architectures such as the Motorola 68000.
Motorola's success with the 68000 led to the MC68010, which added
virtual memory support. The MC68020, introduced in 1985 added full 32-bit data
and address busses. The 68020 became hugely popular in the Unix super
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microcomputer market, and many small companies (e.g., Altos, Charles River
Data Systems) produced desktop-size systems. Following this with the MC68030,
which added the MMU into the chip, the 68K family became the processor for
everything that wasn't running DOS. The continued success led to the MC68040,
which included an FPU for better math performance. A 68050 failed to achieve its
performance goals and was not released, and the follow-up MC68060 was
released into a market saturated by much faster RISC designs. The 68K family
faded from the desktop in the early 1990s.
Other large companies designed the 68020 and follow-ones into
embedded equipment. At one point, there were more 68020s in embedded
equipment than there were Intel Pentiums in PCs. The Cold Fire processor cores
are derivatives of the venerable 68020.
During this time (early to mid 1980s), National Semiconductor introduced
a very similar 16-bit pin out, 32-bit internal microprocessor called the NS 16032
(later renamed 32016), the full 32-bit version named the NS 32032, and a line of
32-bit industrial OEM microcomputers. By the mid-1980s, Sequent introduced
the first symmetric multiprocessor (SMP) server-class computer using the NS
32032. This was one of the design's few wins, and it disappeared in the late
1980s.
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Other designs included the interesting Zilog Z8000, which arrived too late to
market to stand a chance and disappeared quickly.
In the late 1980s, "microprocessor wars" started killing off some of the
microprocessors. Apparently, with only one major design win, Sequent, the NS
32032 just faded out of existence, and Sequent switched to Intel microprocessors.
64-bit microchips on the desktop
While 64-bit microprocessor designs have been in use in several markets
since the early 1990s, the early 2000s have seen the introduction of 64-bit
microchips targeted at the PC market. With AMD's introduction of the first 64-bit
IA-32 backwards-compatible architecture, AMD64, in September 2003, followed
by Intel's own x86-64 chips, the 64-bit desktop era began. Both processors can
run 32-bit legacy apps as well as the new 64-bit software. With 64-bit Windows
XP and Linux that run 64-bit native, the software too is geared to utilize the full
power of such processors.
In reality the move to 64-bits is more than just an increase in register size
from the ia32 as it also includes a small increase in register quantity for the aging
CISC designs.
The move to 64 bits by PowerPC processors had been intended since the
processor's design in the early 90s and was not a major cause of incompatibility.
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Existing integer registers are extended as are all related data pathways but in
common with the IA32 designs both floating point and vector units had been
operating at or above 64 bits for several years. Unlike the IA32 no new general
purpose registers are added so any performance gained when using the 64-bit
mode is minimal.
RISC
In the mid-1980s to early-1990s, a crop of new high-performance RISC
(reduced instruction set computer) microprocessors appeared, which were initially
used in special purpose machines and Unix workstations, but have since become
almost universal in all roles except the Intel-standard desktop.
The first commercial design was released by MIPS Technologies, the 32-
bit R2000 (the R1000 was not released). The R3000 made the design truly
practical, and the R4000 introduced the world's first 64-bit design. Competing
projects would result in the IBM POWER and Sun SPARC systems, respectively.
Soon every major vendor was releasing a RISC design, including the AT&T
CRISP, AMD 29000, Intel i860 and Intel i960, Motorola 88000, DEC Alpha and
the HP-PA.
Market forces have "weeded out" many of these designs, leaving the
PowerPC as the main desktop RISC processor, with the SPARC being used in
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Sun designs only. MIPS continues to supply some SGI systems, but is primarily
used as an embedded design, notably in Cisco routers. The rest of the original
crop of designs have either disappeared, or are about to. Other companies have
attacked niches in the market, notably ARM, originally intended for home
computer use but since focused at the embedded processor market. Today RISC
design based on the MIPS, ARM or PowerPC core power the vast majority of
computing device. In 64-bit computing, DEC Alpha, AMD64, MIPS, SPARC,
Power Architecture, and HP-Intel Itanium are all popular designs.
Special-purpose microprocessors
Though the term "microprocessor" has traditionally referred to a single- or
multi-chip CPU or System-on-a-chip (SoC), several types of specialized
processing devices have followed from the technology. The most common
examples are microcontrollers, Digital Signal Processors (DSP) and Graphics
processing units (GPU). Many examples of these are either not programmable, or
have limited programming facilities. For example, in general GPUs through the
1990s were mostly non-programmable and have only recently gained limited
facilities like programmable vertex shedders. There is no universal consensus on
what defines a "microprocessor", but it is usually safe to assume that the term
refers to a general-purpose CPU of some sort and not a special-purpose processor
unless specifically noted.
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The RCA 1802 had what is called a static design, meaning that the clock
frequency could be made arbitrarily low, even to 0 Hz, a total stop condition. This
let the Voyager/Viking/Galileo spacecraft use minimum electric power for long
uneventful stretches of a voyage. Timers and/or sensors would awaken/speed up
the processor in time for important tasks, such as navigation updates, attitude
control, data acquisition, and radio communication.
Microprocessor Progress: INTEL
Figure 1.5
The Intel 8080 was the first microprocessor in a home computer
The first microprocessor to make it into a home computer was the Intel
8080, a complete 8-bit computer on one chip, introduced in 1974. The first
microprocessor to make a real splash in the market was the Intel 8088, introduced
in 1979 and incorporated into the IBM PC (which first appeared around 1982). If
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you are familiar with the PC market and its history, you know that the PC market
moved from the 8088 to the 80286 to the 80386 to the 80486 to the Pentium to the
Pentium II to the Pentium III to the Pentium 4. All of these microprocessors are
made by Intel and all of them are improvements on the basic design of the 8088.
The Pentium 4 can execute any piece of code that ran on the original 8088, but it
does it about 5,000 times faster!
The following table helps you to understand the differences between the
different processors that Intel has introduced over the years.
Name Date Transistors Microns Clock speed
Data width MIPS
8080 1974 6,000 6 2 MHz 8 bits 0.64
8088 1979 29,000 3 5 MHz16 bits8-bit bus
0.33
80286 1982 134,000 1.5 6 MHz 16 bits 1
80386 1985 275,000 1.5 16 MHz 32 bits 5
80486 1989 1,200,000 1 25 MHz 32 bits 20
Pentium 1993 3,100,000 0.8 60 MHz32 bits64-bit bus
100
Pentium II 1997 7,500,000 0.35 233 MHz
32 bits64-bit bus
~300
Pentium III 1999 9,500,000 0.25 450 MHz
32 bits64-bit bus
~510
Pentium 4 2000 42,000,000 0.18 1.5 GHz
32 bits64-bit bus
~1,700
Pentium 4 2004 125,000,000 0.09 3.6 32 bits ~7,000
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"Prescott" GHz 64-bit bus
Table 1.0
The Intel Microprocessor Quick Reference Guide and TSCP Benchmark Scores
Information about this table:
The date is the year that the processor was first introduced. Many
processors are re-introduced at higher clock speeds for many years after
the original release date.
A Transistors is the number of transistors on the chip. You can see that
the number of transistors on a single chip has risen steadily over the years.
A micron is the width, in microns, of the smallest wire on the chip. For
comparison, a human hair is 100 microns thick. As the feature size on the
chip goes down, the number of transistors rises.
Clock speed is the maximum rate that the chip can be clocked at. Clock
speed will make more sense in the next section.
Data Width is the width of the ALU. An 8-bit ALU can
add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can
manipulate 32-bit numbers. An 8-bit ALU would have to execute four
instructions to add two 32-bit numbers, while a 32-bit ALU can do it in
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one instruction. In many cases, the external data bus is the same width as
the ALU, but not always. The 8088 had a 16-bit ALU and an 8-bit bus,
while the modern Pentiums fetch data 64 bits at a time for their 32-bit
ALUs.
MIPS stand for "millions of instructions per second" and is a rough
measure of the performance of a CPU. Modern CPUs can do so many
different things that MIPS ratings lose a lot of their meaning, but you can
get a general sense of the relative power of the CPUs from this column.
From this table you can see that, in general, there is a relationship between
clock speed and MIPS. The maximum clock speed is a function of the
manufacturing process and delays within the chip. There is also a
relationship between the number of transistors and MIPS. For example,
the 8088 clocked at 5 MHz but only executed at 0.33 MIPS (about one
instruction per 15 clock cycles). Modern processors can often execute at a
rate of two instructions per clock cycle. That improvement is directly
related to the number of transistors on the chip and will make more sense
in the next section.
Statistics of the microprocessor
YEAR CHIP INNOVATION APPLICATIONS PROBLEMS
1971 Intel 4004 First "computer-on-a-chip"
Arithmetic , i.e. Busicom calculator
Limited resources
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1972 Intel 80088-bit bus width; first to implement interrupts
Dumb terminals, calculators, bottling machines
Interrupts worked poorly
1972Texas InstrumentsTMS 1000
On-chip memory Low-cost embedded applications
Programmers couldn't add external memory
1974 Intel 8080
10x performance of the 8008; separate address and data buses
Altair computer (first PC); traffic light controller
Difficult to program
1978 Intel 8086 16-bit bus width Desktop and portable computing
Convoluted addressing scheme
1979 Motorola 68000
16-/32-bit chip powerful enough to handle advanced graphics
Apple Lisa ('83), Unix workstations, home videogame machines
Integer unit and ex-ternal data bus only 16 bits wide
1979 Intel 808816-bit internal architecture with 8-bit external bus
IBM PCs and clones
Same convoluted addressing scheme as the 8086
1982 Intel 80286
Added memory protection; 16 MB of addressable memory; 1GB of virtual memory
Standard PC CPU
Couldn't do page faults, lacked virtual memory
1985 Intel 386 DX
64 terabytes of virtual memory; 32-bit bus; 4-GB addressable memory
Desktop PCs
Didn't yet have an on-chip FPU or on-chip cache
1986 MIPS Computer Systems
First motherboard-level RISC chip for
Unix workstations; later, midrange computers
Difficult to program; incompatible
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R2000 workstations with PC software
1987Sun MicrosystemsSPARC
An open RISC architecture
Laptops to workstations to supercomputers
Required multiple chips due to pair of CMOS gate arrays and external FPUs
1989 Intel i486
First x86 with on-chip cache, FPU, and pipelined instructions
Desktop PCs, CAD
Lacked advanced techniques of some RISC chips
1989 Intel i960CA First superscalar chip
Primarily embedded applications
Fairly expensive
1992
Digital Equipment Corp.Alpha 21064
200-MHz clock Workstations and servers
Ran hot; expensive
1993IBM and MotorolaPowerPC 601
First out-of-order execution microprocessor
Apple Macintoshes, desktop PCs, servers
Programs not usually written for out-of-order execution
1993 Intel Pentium
Dynamic branch prediction; 64-bit external data bus and 32-bit address bus
Desktop PCs and network servers Ran very hot
1995
Digital Equipment Corp.Alpha 21164
First to execute four instructions per cycle and the first with three on-chip caches
High-end desktop PCs, workstations, and servers
Runs hot; expensive
1995 Intel Pentium Pro
Has CPU chip and cache chip in same package
High-end desktop computers, graphics workstations,
Expensive
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servers
Figure 1.1
Microprocessor statistical
Microprocessor Comparison
There are many microprocessors available to the public. Not knowing the
differences can be quite frustrating -- especially when it means saving or spending
a couple hundred dollars.
Below is a chart that compares and contrasts important features found on some of
the more popular chips in the market today.
Celeron
Pentium II
Pentium III
Pentium III Xeon
Pentium 4
K6-II
K6-III
Athlon (K7)
Athlon XP
Duron
PowerPC G3
PowerPC G4
Transistors
7,500,000
7,500,000
9,500,000
28,100,000
55,000,000
9,300,000
21,300,000
22,000,000
37,500,000
N/A
6,500,000
10,500,000
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CPU Speed
1.06 GHz - 2 GHz
233 MHz - 450 MHz
450 MHz - 1 GHz
500 MHz - 1 GHz
1.4 GHz - 2.2 GHz
500 MHz - 550 MHz
400 MHz - 450 MHz
850 MHz - 1.2 GHz
1.67 GHz
700-800 MHz
233 MHz - 333 MHz
400 MHz - 800 MHz
L2 Cache
256 KB,full speed
512 KB,half speed
256 KB,full speed
256 KB - 2 MB,full speed
256 KB,full speed
N/A
256 KB,full speed
256 KB,full speed
384 KB,full speed
64 KB,full speed
512 KB, 1 MB,half speed
1 MB,half speed
Front-Side Bus Speed
133 MHz and 400 MHz
100 MHz
133 MHz
100 MHz
533 MHz
100 MHz
100 MHz
200 MHz and 266 MHz
266 MHz
200 MHz
100 MHz
100 MHz
Floating Point
strong
strong
strong
strong N/A N/A Stro
ngvery strong
very strong
very strong
very strong
Strong
Integer
strong
strong
strong
strong N/A N/A Exce
llentvery strong N/A N/
A N/A N/A
Table 1.2
Comparison Chart
Microprocessor Instruction
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An instruction is a binary pattern designed inside a microprocessor to
perform a specific function. The entire group of instructions, called the instruction
set, determines what functions the microprocessor can perform. These instructions
can be classified into the following five functional categories: data transfer (copy)
operations, arithmetic operations, logical operations, branching operations, and
machine-control operations.
Data Transfer (Copy) Operations-This group of instructions copy data
from a location called a source to another location called a destination,
without modifying the contents of the source. In technical manuals, the
term data transfer is used for this copying function. However, the term
transfer is misleading; it creates the impression that the contents of the
source are destroyed when, in fact, the contents are retained without any
modification. The various types of data transfer (copy) are listed below
together with examples of each type:
Arithmetic Operations-These instructions perform arithmetic operations
such as addition, subtraction, increment, and decrement.
Addition - Any 8-bit number, or the contents of a register or the contents
of a memory location can be added to the contents of the accumulator and
the sum is stored in the accumulator. No two other 8-bit registers can be
added directly (e.g., the contents of register B cannot be added directly to
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the contents of the register C). The instruction DAD is an exception; it
adds 16-bit data directly in register pairs.
Subtraction - Any 8-bit number, or the contents of a register, or the
contents of a memory location can be subtracted from the contents of the
accumulator and the results stored in the accumulator. The subtraction is
performed in 2's compliment, and the results if negative, are expressed in
2's complement. No two other registers can be subtracted directly.
Increment/Decrement - The 8-bit contents of a register or a memory
location can be incremented or decrement by 1. Similarly, the 16-bit
contents of a register pair (such as BC) can be incremented or decrement
by 1. These increment and decrement operations differ from addition and
subtraction in an important way; i.e., they can be performed in any one of
the registers or in a memory location.
Logical Operations-These instructions perform various logical operations
with the contents of the accumulator.
AND, OR Exclusive-OR - Any 8-bit number, or the contents of a register, or of a
memory location can be logically ANDed, Ored, or Exclusive-Ored with the
contents of the accumulator. The results are stored in the accumulator.
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Rotate- Each bit in the accumulator can be shifted either left or right to
the next position.
Compare- Any 8-bit number or the contents of a register, or a memory
location can be compared for equality, greater than, or less than, with the
contents of the accumulator.
Complement - The contents of the accumulator can be complemented. All
0s are replaced by 1s and all 1s are replaced by 0s.
Branching Operations
This group of instructions alters the sequence of program execution either
conditionally or unconditionally.
Jump - Conditional jumps are an important aspect of the decision-making
process in the programming. These instructions test for a certain
conditions (e.g., Zero or Carry flag) and alter the program sequence when
the condition is met. In addition, the instruction set includes an instruction
called unconditional jump.
Call, Return, and Restart - These instructions change the sequence of a
program either by calling a subroutine or returning from a subroutine. The
conditional Call and Return instructions also can test condition flags.
Machine Control Operations
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These instructions control machine functions such as Halt, Interrupt, or do
nothing. The microprocessor operations related to data manipulation can be
summarized in four functions:
1. Copying data
2. Performing arithmetic operations
3. Performing logical operations
4. Testing for a given condition and alerting the program sequence
Some important aspects of the instruction set are noted below:
1. In data transfer, the contents of the source are not destroyed; only the contents
of the destination are changed. The data copy instructions do not affect the flags.
2. Arithmetic and Logical operations are performed with the contents of the
accumulator, and the results are stored in the accumulator (with some
expectations). The flags are affected according to the results.
3. Any register including the memory can be used for increment and decrement.
4. A program sequence can be changed either conditionally or by testing for a
given data condition.
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Microprocessor Trends
Dual-core microprocessors are currently the center of attention in
computing design. There is a definite shift away from ever higher frequencies to
multicore processors to meet higher-performance requirements without pushing
power consumption beyond what can be tolerated in many applications.
Figure 1.6
A single-core processor needing a large heat sink doesn’t
Suit most embedded applications.
Other significant developments that are focused on delivering “more
MIPS per watt” include on-chip memory controllers, more sophisticated dynamic
power management and the growth of single-instruction multiple-data (SIMD)
engines. Process and transistor technologies have been the primary means to
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higher processor performance driven by higher frequencies. Recently, however,
the focus has moved away from frequency and onto power consumption. Until
recently, designers’ primary power consideration was the AC component because
of the charging and discharging of gates.
Dual-core processors
HF devices require higher voltage supplies and, therefore, exponentially
higher power-consumption and dissipation allowances. Increased interrupt
latencies, which are critical in real-time applications, are also a product of higher-
frequency processors that require deeper pipelines to feed the core. Stalls caused
by pipeline flushes—this happens when the processor takes an unpredicted branch
in code—can seriously impact performance. Other factors are forcing chip
designers to find performance gains by new means. Higher frequencies require
additional clocking overhead. A safety margin has to be built into processors
around the clock edges to ensure correct operation. Since the safety margin
remains approximately constant, there is effectively less usable time within a
clock period as the frequency increases. Thus, increased frequencies have not
been delivering similar levels of performance. Hence, system designers are
moving toward multicore processor architectures rather than higher-frequency
devices to enable higher system performance while minimizing increases in
power consumption. Dual-core microprocessors, originally conceived for
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computationally intensive applications such as servers, are now being designed
and deployed across a range of embedded application
Microprocessor Units
The Z80180™ is an 8-bit MPU which provides the benefits of reduced
system costs and also provides full backward compatibility with existing ZiLOG
Z80 devices. Reduced system costs are obtained by incorporating several key
system functions on-chip with the CPU. These key functions include I/O devices
such as DMA, UART, and timer Z80180
Figure 1.8
Functional Block Diagram
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Figure 1.9
Block diagram
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Chapter 3DEVELOPMENT OF THE PROJECT
Project Development
Figure 1.7
The two experimenter board for the MSP430 chipset. On the left
the larger chip version, on the right a small version in USB format.
A Microprocessor Development Board is a printed circuit board
containing a microprocessor and the minimal support logic needed for an
engineer to become acquainted with the microprocessor on the board, and to
learn to do some elementary assembler programming on it. It also served for the
producer of the microprocessor as a platform for testing their new chip.
It differs from a home computer by not having any logic above what is
absolutely necessary to create a working system with an ability to enter and
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execute a machine language program, and evaluate the result. So normally all
the things you would expect to have in a computer system designed for
entertainment, such as a Video Display Controller, a sound-chip, and a keyboard
usable for Basic, would not be available as a standard feature.
Synthesis and Development Procedure of Microprocessor Software
Program for Spacecraft Digital Attitude Control
A systematic procedure is developed for the synthesis of attitude
control software for three-axis stabilized satellites. In discussing the
systematic procedure, emphasis is placed on the fixed-point arithmetic
scaling strategy, and three types of simulation. These simulation
processes are: numerical simulation on a large-scale digital computer; full-
instruction simulation for the digital controller with dynamics simulated
numerically; and hardware simulation using an air bearing table on which
are mounted sensors, actuators, and a microcomputer adopted for the
prototype attitude controller.
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CHAPTER IV
Summary, Conclusion and Recommendation
Summary
Microprocessor they have three Units of 8085 first Processing Unit, Instruction
Unit, Storage and Interface Unit.
Processing unit it is arithmetic and logic unit, accumulator, status flag and
temporary register
Instruction Unit it is Instruction Register ,Instruction Decoder, Timing and
Control Unit
6
Conclusion
In this project, simulation of Intel 8085 microprocessor instructions on a
different CPU and operating system is discussed. For this purpose, a program,
which called as Sim8085, is written in a high level visual language on an Intel
80386 based CPU and Windows 95 based operating system. For the point of
engineering, program developing on an 8085-µp environment is hard and hence,
means that losing time. With the Sim8085, writing 8085-µp assembly language
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based algorithms and checking them for error is so much easy; Sim8085 has come
over all these difficulties easily.
The Intel 8085 is an 8-bit microprocessor introduced by Intel in 1977. It
was binary-compatible with the more-famous Intel 8080 but required less
supporting hardware, thus allowing simpler and less expensive microcomputer
systems to be built. The "5" in the model number came from the fact that the 8085
required only a +5-volt (V) power supply rather than the +5V, -5V and +12V
supplies the 8080 needed. Both processors were sometimes used in computers
running the CP/M operating system, and the 8085 later saw use as a
microcontroller, by virtue of its low component count. Both designs were eclipsed
for desktop computers by the compatible Zilog Z80, which took over most of the
CP/M computer market as well as taking a share of the booming home computer
market in the early-to-mid-1980s.The 8085 had a long life as a controller. Once
designed into such products as the DEC tape controller and the VT100 video
terminal in the late 1970s, it continued to serve for new production throughout the
life span of those products (generally longer than the product life of desktop.
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APPENDICES