Eureka Electrosoft Solutions Pvt. Ltd. - EESPL · Eureka Electrosoft Solutions Pvt. Ltd. E u r e k a E m b e d d e d & A d v a n c e d S o f t w a r e T e c h n o l o g i e s Page

Eureka Electrosoft Solutions Pvt. Ltd.

E u r e k a E m b e d d e d & A d v a n c e d S o f t w a r e T e c h n o l o g i e s ( E E A S T )

A T r a i n i n g U n i t o f E u r e k a E l e c t r o s o f t S o l u t i o n s P v t . L t d .

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Company Profile




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EUREKA ELECTROSOFT SOLUTIONS PVT. LTD (EESPL)

……..making IT happen

Augmentation is a dream virtue of every performer – we at EESPL

envisaged on a theme for providing a new epitome of IT solutions in the

embedded Telecom & Software based Product development services. Our

edge right from the start was creating a perceptible differentiation among the

plethora of communized IT solutions.

EESPL - where progress is a winning habit

Eureka ElectroSoft Solutions Pvt. Ltd. (EESPL) is primarily operating as

a registered R & D lab for the development and conception of Advanced

Automation related software and hardware solutions. Our expertise includes

electronics and software based stand alone solutions as well as combined

integrated solutions termed as “Electrosoft Solutions”. At EESPL over the

years we have developed a core competency to maximize the quality &

innovation parameter while working on any task. Our proven values

have made us as a prime leader in providing customized solutions.

It is our stiff endeavor to amplify our clients viewpoints and to carve up

their thoughts. This in turn is transformed into factual scenario

working models with a collection of prime technological aspects. All this is

and much more in the shortest turnaround period.

EESPL – the background and essence of operations

The year 2002 witnessed the birth of a visualization – which was to impart

economy with a pinnacle swiftness of innovation in contemporary Industrial

IT Solutions. There came EESPL and a new chapter of imparting excellence

in IT techniques came into subsistence.

That was the foundation and today the road voyaged by EESPL

encompasses years of reliance, accomplishments and above all unlimited

bonds. Bonds that speak for themselves, relationships that reflect factual

progress. Triumph at EESPL is defined as the never ending smile on our

dear customer‘s face. At EESPL we do not impart conception, we create

endearing teams.




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Indulging within minds, Imparting technologies

Understanding the pulsation of a customer forms our principal challenge.

Assurances that mean results, efforts that capitulate advancement and

outcomes that move imaginings form the spirit of our day after day working.

Timeliness is of chief value to us and understanding the modern day race for

time, we deliver the maximum in minimum and that too with precision.

Our approach of operation also constitutes of a dedicated Registered

Research and Development lab to make available the final deliverables with

thread bare technologies.

Our precedence is often devised on the scale of our customer‘s desires. After

carefully analyzing on the need based approach we craft a well planned set

of operations – each fragment is build with an in depth focus on customer‘s

requirements.




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Vision & Mission:

Our corporate vision is to provide a fully functional IT platform to all

complex tasks thereby inducing a greater sense of effectiveness and to

consistently create value for money, by providing solutions which enable our

customers to achieve excellence and sustainable competitive edge.

Mission target

Our mission statement is to provide endearing technologies of future in the

present era and for that we are committed to develop innovative and the

most valuable solutions to our customers as our motto is “Changing Ideas

into Reality”.

Our Core Values:

Innovation

Flexibility is the key to our offerings, and intrinsic to this flexibility, is the

spirit of

Innovation that we bring to our products and services - from the very first

stage of design to implementation and customer support.

Competence

At EESPL we always pride ourselves on the vision, skills, expertise and

professionalism of our team. Our team members make use of their keen

Competence to foresee industry trends and meet demanding customer

needs. And the working of their collective minds in a highly supportive

environment ensures that our products and services retain a competitive edge

at all times.

Quality Objectives

Quality forms the basis of our work culture. To impart the right and the

leading technology, we follow the most rigorous norms. Each of our product

stage goes through multi check points. Every possible situation is thought of

and a remedial action is built in. The presence of our dedicated Quality




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Analysis team makes sure that the minutest details are met with precision.

We fully understand the global quality perspective and we follow in tandem

with the same.

QUALITY TESTING

Extensive industry exposure, expanded skills and comprehensive experience

in executing key projects for reputed global companies enable us to bring

world-class technology, true-value professional expertise & immense

knowledge of successful project management.

Quality Assurance is one of the key focus areas and once a solution is

developed, our Software Testing Team steps in to perform the rigorous

rituals, required to deliver a robust, flawless product/application. Software

testing at Olive is performed at several points in the Software Development

Life Cycle (SDLC), as an application is constructed component by

component into a functioning system. Our qualified testers carry out intense

testing for bugs and flaws and fix the same - all within the strictest time

frame.

CUSTOMER SUPPORT AND FEEDBACK REVIEW

EESPL at your doorstep

Ensuring total customer satisfaction is EESPL‘s forte and the company has

implemented an effective customer relationship management strategy for

increased efficiency and overall success. From project kick-off to customer

sign-off, Eureka's dedicated Managers will work in tandem with you and

provide round-the-clock updates on project status. They also solve problems,

answer queries and give instant feedback. Eureka provides 24x7 online

support, proposed (each customer query will be immediately recorded and a

ticket number will be issued for future reference).




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After the project delivery, each customer is requested to provide feedback on

a number of relevant criteria such as delivery schedule, product quality,

issue resolution, communication, risk management, knowledge and

professionalism. After obtaining the critical information through relevant

questionnaires, we make an in-depth analysis of the valuable data and

measure customer satisfaction at all levels. EESPL also encourages peer

reviews for enhancing cross-functional co-ordination and strengthening

quality initiatives

Olive believes in partnerships - partnerships that develop into mutually

beneficial symbiotic relationships brandishing the competitive edges of both.

With Olive's Internet technology as expertise, you can compete with the

world's premium e-business solution providers and develop a technology

EESPL not just delivers online presence but specializes in employing its

technology to help clients make the most of their online presence. We

strategize and impart technical applications, marketing and design skills

required maximizing a company's online potential.

WHY EESPL

Well, its got to be somebody. Why not us? Of course, you are the best judge

when it comes to choosing a technology partner and we leave that for you to

decide. Our goal is only to provide a clear and detailed insight into your

project work and possible expansion plan when the time comes. First and

foremost, we never compromise on quality. Any and all work, big or small,

is important to us. We believe in delivering high quality products that

exceeds client‘s expectations. Second, our experienced architects help you

design a product that is far more powerful and open when it comes to

enhancements. Third, we are delivery oriented and believe in delivering no

matter what it takes. We provide cost effect solutions at competitive prices

to ensure your ROI is high and budget is well under control. With those said,

we leave the call on you to decide ‗Why us?‘




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Eureka Electronics & Embedded Solutions (E3S):

Mastering the art of aptness

Electronic product design is the result of integrated proficiency covering both the

software and the electronic/hardware design facets. With our proficient Design Centre on

the anvil, a panel of devoted experienced engineers works as a team to provide a highly

receptive and customized service solutions. Each perspective of customer service is

performed with paramount flawlessness thereby inducing a path full of aptness. At E3S

order goes hand in hand with the final conclusion. We very well understand the throb of

the client and it is our primary intent to form a cohesive plan of action. Understanding on

a common platform with the client forms the chief medium of our achievement.

Components of our Project work – putting able brains to work

Converting simple ideas to real time products

Enhancing the performance aptitude of existing products

In depth investigations into offered technologies

Testing & Verifications of numerous assignments

The Execution Schedule – implementing the knowledge minds

What we require is simply a brief of the requirements, which can be documented or can

be the result of an able discussion. The upshot of the same is a firm proposal from our

side which is entirely Free of cost.




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Eureka Telecom & Infrastructure Services(ETIS):

Connecting Emotions

Our venture into the turf of Telecom Network Services has been under the aegis of

Eureka Telecom Solutions. Our principal focal point in this sphere is to fuse diverse

expertise for catering to Telecom Networking, Communication & Infrastructure

maintenance needs of globally distributed Enterprises and Telecom Carriers (GSM &

CDMA).

Our laurels in segment sector include associations with variety of renowned Telecom

players such as SPICE, VODAFONE, RELIANCE, ERICSSON, SIEMENS, NOKIA

and ZTE. On the offerings are telecom site installation and commissioning, BSC &

Transcoder Installation & Commissioning, BSS support and Maintenance, Installation of

MSCs, Electrical resourcing and installation. In addition to above utilities, we are also

diligently developing hardware and software based automation gear for TELECOM

sector.




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Eureka Smart Software Solutions(E3S) :

Placing Thoughts into Implementation

Software Development at E3S forms a perceptible and exceedingly expertised service

which gratifies to the requirements of landmark technology projects for software

companies and large enterprise clients. The spotlight of this function is to generate a

eminent conception with faster time to-market and condensed engineering costs. Working

hand in glove with our clientele, their personalized wants for product development

projects are met with absolute knack.

Another pioneering concept envisaged by E3S is the provision of software architecture

analysis to make certain the solution being offered can be capably designed, developed

and supported. E3S proficiency extents to various industry facades and technology

spectrums. Our association with customers inculcates an innovative wave of product

development which in turn creates intelligent solutions that drastically cut down

operating costs. All this momentum adds to greater induced efficiency. Some real life

technologies covered by us in software development are: Desktop and Web

applications, Client/Server based applications, Telecom related software tools

development, Biometric based identification and account solutions, RFID based

applications, Biomedical Viewers and related software development, Image

processing and enhancement tools, GSM/CDMA based bulk SMS alerting systems,

Reengineering and Migration etc.




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Eureka Embedded & Advanced Software Trainings(EEAST)

Preparing the Visionaries of Tomorrow …Today

Right from origin Eureka Electrosoft Solutions emerged as a futurist leader in industrial,

corporate training and engineering project assistance. Covering the grounds of embedded

and advanced software technologies it was aptly christened as ElectroSoft Embedded &

Advanced Software Technologies (EEAST).

EEAST is a name to reckon with for the engineering project guidance workshops and

trainings. In trainings the foremost emphasis is laid on covering the gap between the

theoretical and real practical aspects of the technology.

What is done by mind is seldom forgotten, but, what is done by hand is remembered a

lifetime. Based on this principle our Training & Project oriented workshops create a

foundation of real time project based culture. All this goes a long way in creating learning

by doing methodology wherein the wisdom is mastered perfectly.

Since the invent of copious training kits and development boards is completely in-

house, hence there is no dearth of functional training resources. Provision flexible

training modules ranging from one month to six months durations, provide a success

oriented launcpad. Each module is carefully crafted to nurture the students with practical

aspects as well as the theoretical concepts which they have harvested during the general

curriculum process. In campus and corporate trainings also form the serviceable phase of

EEAST.




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Eureka Human Resources & Turnkey Support Solutions(EHRTSS)

Fostering Proficient Intellect

Today‘s contemporary industry requires dexterous wits to work on extensive global

dares. We fully recognize the types of individuals required for high end IT programmes.

Human resources form the base of every organization and we also have a share in putting

weight to this base. We provide capable man power in fine execution of complexed IT

programmes. Noted professionals from various fields are on our database, hence we have

distinguished corporates, like Vodafone and Spice Telecommunications on our client

list.

Benefits to an operator

prompt deployment of resources

complete compliant with local work regulations

Provision of unrestricted series of skills

Existence of skilled consultants with training on precise equipment & software.

The alternative also exists wherein the entire project can be executed by us on turn key

basis. Examples of turnkey work we provide are Line Of Sight Survey, RF and TR

Planning, Pre-Bid and Swap-outs




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Eureka Project Kits and Spares (EPKS)

For an Uninterrupted Performance & Adept Learning

EEAST is today a well trusted partner of thousands of hobbyists, OEMs, Colleges, schools,

repair shops and Government Organizations for electronics kits and spares. Our wide range of

stock comprises of everything ranging from electronics components to test instruments and

extending to educational kits. Principally we deal in Project oriented Hardware kits, Robotic

kits, Device Programmers, Development Boards, Software tools, Components etc. These

inventive kits are of leading advantage for engineering students from all branches. Their projects

can be developed with simplicity using these kits as they are very undemanding to grasp and

employ. Component resourcing for the students at their own places with the minimum market

cost is also undertaken by us.




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Training Modules




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Introduction

Technology has rapidly grown in past two-three decades. An engineer without

practical knowledge and skills cannot survive in this technical era. Theoretical

knowledge does matter but it is the practical knowledge that is the difference

between the best and the better. Organizations also prefer experienced engineers

than fresher ones due to practical knowledge and industrial exposure of the

former. So industrial exposure is mandatory for engineers nowadays. The practical

training is highly conductive for solid foundation for:

1) Knowledge and personality. 2) Confidence building 3) Enhancement of

creativity.

Embedded Systems are present every where around us like from a simple digital

wrist watch to the most complex satellite space ships. All entities involving

automation are equipped with embedded systems.

At the core of every embedded system there is either a microprocessor or a

microcontroller or any other programmable intelligent unit that works with the

other interfaced units to make a complete working product. So in ongoing

cutthroat competition it is mandatory for every engineer to understand and become

proficient in this upcoming technology.

Embedded systems are computers which are part of special-purpose devices. Due

to the limited duties these systems can be highly optimized to the particular needs.

Traditionally most of these systems are used for control and process measurement,

as a side-effect of higher integration of integrated circuits more complex

applications can be solved by embedded systems. To be able to solve these

problems, embedded systems are commonly equipped with various kinds of

peripherals. Early applications of embedded devices include the guidance

computer of the Minuteman I missiles and the Apollo guidance computer. The

Minuteman I & II missiles are intercontinental ballistic nuclear warheads,

produced by Boeing in the 1960‘s. Due to the large quantities of ICs used in the

guidance system of Minuteman II missiles, prices for ICs fell from 1000$ each to

3$ each. This lead to wide adoption of embedded systems in consumer electronics




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in the 1980‘s. Nowadays embedded systems can be found in devices from digital

watches to traffic-control systems. The broad range of applications with totally

different requirements lead to various implementation approaches. The range of

hardware used in embedded systems reaches from FPGAs to full blown desktop

CPUs which are accompanied by special purpose ICs such as DSPs. On the

software side, depending on the needs, everything, from logic fully implemented

in hardware, to systems with own operating system and different applications

running on it, can be found.

'




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Module -1

POWER SUPPLY DESCRIPTION:

The power supply circuit comprises of four basic parts:

The transformer steps down the 220 V a/c. into 12 V a/c. The transformer

work on the principle of magnetic induction, where two coils: primary and

secondary are wound around an iron core. The two coils are physically

insulated from each other in such a way that passing an a/c. current through

the primary coil creates a changing voltage in the primary coil and a

changing magnetic field in the core. This in turn induces a varying a/c.

voltage in the secondary coil.

The a/c. voltage is then fed to the bridge rectifier. The rectifier circuit is used

in most electronic power supplies is the single-phase bridge rectifier with

capacitor filtering, usually followed by a linear voltage regulator. A rectifier

circuit is necessary to convert a signal having zero average value into a non-

zero average value. A rectifier transforms alternating current into direct

TRANSFORMER

SHUNT

CAPACITOR

BRIDGE

RECTIFIER

VOLTAGE

REGULATOR




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current by limiting or regulating the direction of flow of current. The output

resulting from a rectifier is a pulsating D.C. voltage. This voltage is not

appropriate for the components that are going to work through it.

1N4007

12-0-12 V

1000uF

O/P

16 V

TRANSFORMER

The ripple of the D.C. voltage is smoothened using a filter capacitor of 1000

microF 25V. The filter capacitor stores electrical charge. If it is large enough

the capacitor will store charge as the voltage rises and give up the charge as

the voltage falls. This has the effect of smoothing out the waveform and

provides steadier voltage output. A filter capacitor is connected at the

rectifier output and the d.c voltage is obtained across the capacitor. When

this capacitor is used in this project, it should be twice the supply voltage.

When the filter is used, the RC charge time of the filter capacitor must be

short and the RC discharge time must be long to eliminate ripple action. In

other words the capacitor must charge up fast, preferably with no discharge.

When the rectifier output voltage is increasing, the capacitor charges to the

peak voltage Vm. Just past the positive peak, the rectifier output voltage

starts to fall but at this point the capacitor has +Vm voltage across it. Since

the source voltage becomes slightly less than Vm, the capacitor will try to

send current back through the diode of rectifier. This reverse biases the

7805




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diode. The diode disconnects or separates the source the source form load.

The capacitor starts to discharge through load. This prevents the load voltage

from falling to zero. The capacitor continues to discharge until source

voltage becomes more than capacitor voltage. The diode again starts

conducting and the capacitor is again charged to peak value Vm. When

capacitor is charging the rectifier supplies the charging through capacitor

branch as well as load current, the capacitor sends currents through the load.

The rate at which capacitor discharge depends upon time constant RC. The

longer the time constant, the steadier is the output voltage. An increase in

load current i.e. decrease in resistance makes time constant of discharge path

smaller. The ripple increase and d.c output voltage V dc decreases.

Maximum capacity cannot exceed a certain limit because the larger the

capacitance the greater is the current required to charge the capacitor.

The voltage regulator regulates the supply if the supply if the line voltage

increases or decreases. The series 78xx regulators provide fixed regulated

voltages from 5 to 24 volts. An unregulated input voltage is applied at the IC

Input pin i.e. pin 1 which is filtered by capacitor. The out terminal of the IC

i.e. pin 3 provides a regular output. The third terminal is connected to

ground. While the input voltage may vary over some permissible voltage

12

3VIN

GN

DVOUT

- -

1N

40

07

+

I\P(12V)

-

+

OU

TP

UT

GR

OU

ND

+

-

7805

470 E

LED

T1

220 V AC

1 5

4 8

J2

12

D1

-

D2

O\P(5V)

-

-

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+

C1

10

00

UF

D3

+D4

+




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range, and the output voltage remains constant within specified voltage

variation limit. The 78xx IC‘s are positive voltage regulators whereas 79xx

IC‘s are negative voltage regulators.

These voltage regulators are integrated circuits designed as fixed voltage

regulators for a wide variety of applications. These regulators employ

current limiting, thermal shutdown and safe area compensation. With

adequate heat sinking they can deliver output currents in excess of 1 A.

These regulators have internal thermal overload protection. It uses output

transistor safe area compensation and the output voltage offered is in 2% and

4% tolerance.




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MODULE 2:

THE MICROCONTROLER:

In our day to day life the role of micro-controllers has been immense. They

are used in a variety of applications ranging from home appliances, FAX

machines, Video games, Camera, Exercise equipment, Cellular phones

musical Instruments to Computers, engine control, aeronautics, security

systems and the list goes on.

MICROCONTROLLERS VERSUS MICROPROCESSORS

What is the difference between a microprocessor and microcontroller? The

microprocessors (such as 8086,80286,68000 etc.) contain no RAM, no ROM

and no I/O ports on the chip itself. For this reason they are referred as

general- purpose microprocessors. A system designer using general- purpose

microprocessor must add external RAM, ROM, I/O ports and timers to make

them functional. Although the addition of external RAM, ROM, and I/O

ports make the system bulkier and much more expensive, they have the

advantage of versatility such that the designer can decide on the amount of

RAM, ROM and I/o ports needed to fit the task at hand. This is the not the

case with microcontrollers. A microcontroller has a CPU (a microprocessor)

in addition to the fixed amount of RAM, ROM, I/O ports, and timer are all

embedded together on the chip: therefore, the designer cannot add any

external memory, I/O, or timer to it. The fixed amount of on chip RAM,

ROM, and number of I/O ports in microcontrollers make them ideal for

many applications in which cost and space are critical. In many applications,




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for example a TV remote control, there is no need for the computing power

of a 486 or even a 8086 microprocessor. In many applications, the space it

takes, the power it consumes, and the price per unit are much more critical

considerations than the computing power. These applications most often

require some I/O operations to read signals and turn on and off certain bits.

It is interesting to know that some microcontrollers manufactures have gone

as far as integrating an ADC and other peripherals into the microcontrollers.

EXTERNAL

INTERRUPTS

TXD RXD

MICROCONTROLLER BLOCK DIAGRAM

INTERRUPT CONTROL ON-CHIP ROM for

program code ON-CHIP RAM

ETC.

TIMER 0

TIMER 1

SERIAL

PORT 4 I/O

PORTS

BUS

CONTROL OSC

CPU




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MICROCONTROLLERS FOR EMBEDDED SYSTEMS

In the literature discussing microprocessors, we often see a term embedded

system. Microprocessors and microcontrollers are widely used in embedded

system products. An embedded product uses a microprocessor (or

microcontroller) to do one task and one task only. A printer is an example of

embedded system since the processor inside it performs one task only:

namely, get data and print it. Contrasting this with a IBM PC which can be

used for a number of applications such as word processor, print server,

network server, video game player, or internet terminal. Software for a

variety of applications can be loaded and run. Of course the reason a PC can

perform myriad tasks is that it has RAM memory and an operating system

that loads the application software into RAM and lets the CPU run it. In an

embedded system, there is only one application software that is burned into

ROM. An PC contains or is connected to various embedded products such as

the keyboard, printer, modem, disk controller, sound card, CD-ROM driver,

mouse and so on. Each one of these peripherals has a microcontroller inside

it that performs only one task. For example, inside every mouse there is a

microcontroller to perform the task of finding the mouse position and

sending it to the PC.

Although microcontrollers are the preferred choice for many embedded

systems, there are times that a microcontroller is inadequate for the task. For

this reason, in many years the manufacturers for general-purpose

microprocessors have targeted their microprocessor for the high end of the

embedded market.




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INTRODUCTION TO 8051

In 1981, Intel Corporation introduced an 8-bit microcontroller called the

8051. This microcontroller had 128 bytes of RAM, 4K bytes of on-chip

ROM, two timers, one serial port, and four ports (8-bit) all on a single chip.

The 8051 is an 8-bit processor, meaning the CPU can work on only 8- bit

pieces to be processed by the CPU. The 8051 has a total of four I/O ports,

each 8- bit wide. Although 8051 can have a maximum of 64K bytes of on-

chip ROM, many manufacturers put only 4K bytes on the chip.

The 8051 became widely popular after Intel

allowed other manufacturers to make any flavor of the 8051 they please with

the condition that they remain code compatible with the 8051. This has led

to many versions of the 8051 with different speeds and amount of on-chip

ROM marketed by more than half a dozen manufacturers. It is important to

know that although there are different flavors of the 8051, they are all

compatible with the original 8051 as far as the instructions are concerned.

This means that if you write your program for one, it will run on any one of

them regardless of the manufacturer. The major 8051 manufacturers are

Intel, Atmel, Dallas Semiconductors, Philips Corporation, Infineon.

AT89C51 FROM ATMEL CORPORATION

This popular 8051 chip has on-chip ROM in the form of flash memory. This

is ideal for fast development since flash memory can be erased in seconds

compared to twenty minutes or more needed for the earlier versions of the

8051. To use the AT89C51 to develop a microcontroller-based system

requires a ROM burner that supports flash memory: However, a ROM eraser

is not needed. Notice that in flash memory you must erase the entire contents

of ROM in order to program it again. The PROM burner does this erasing of




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flash itself and this is why a separate burner is not needed. To eliminate the

need for a PROM burner Atmel is working on a version of the AT89C51

that can be programmed by the serial COM port of the PC.

FEATURES OF AT89C51

- 4K on-chip ROM

- 128 bytes internal RAM (8-bit)

- 32 I/O pins

- Two 16-bit timers

- Six Interrupts

- Serial programming facility

- 40 pin Dual-in-line Package

PIN DESCRIPTION

The 89C51 have a total of 40 pins that are dedicated for various functions

such as I/O, RD, WR, address and interrupts. Out of 40 pins, a total of 32

pins are set aside for the four ports P0, P1, P2, and P3, where each port takes

8 pins. The rest of the pins are designated as Vcc, GND, XTAL1, XTAL,

RST, EA, and PSEN. All these pins except PSEN and ALE are used by all

members of the 8051 and 8031 families. In other words, they must be

connected in order for the system to work, regardless of whether the

microcontroller is of the 8051 or the 8031 family. The other two pins, PSEN

and ALE are used mainly in 8031 based systems.

Vcc

Pin 40 provides supply voltage to the chip. The voltage source is +5 V.

GND

Pin 20 is the ground.




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XTAL1 and XTAL2

The 8051 have an on-chip oscillator but requires external

clock to run it. Most often a quartz crystal oscillator is connected to input

XTAL1 (pin 19) and XTAL2 (pin 18). The quartz crystal oscillator

connected to XTAL1 and XTAL2 also needs two capacitors of 30 pF value.

One side of each capacitor is connected to the ground.

C2

XTAL2

C1

XTAL1

GND

It must be noted that there are various speeds of the 8051 family. Speed

refers to the maximum oscillator frequency connected to the XTAL. For

example, a 12 MHz chip must be connected to a crystal with 12 MHz

frequency or less. Likewise, a 20 MHz microcontroller requires a crystal

frequency of no more than 20 MHz. When the 8051 is connected to a crystal

oscillator and is powered up, we can observe the frequency on the XTAL2

pin using oscilloscope.

RST

Pin 9 is the reset pin. It is an input and is active high (normally low).

Upon applying a high pulse to this pin, the microcontroller will reset and

terminate all activities. This is often referred to as a power –on reset.

Activating a power-on reset will cause all values in the registers to be lost.

Notice that the value of Program Counter is 0000 upon reset, forcing the

CPU to fetch the first code from ROM memory location 0000. This means




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that we must place the first line of source code in ROM location 0000 that is

where the CPU wakes up and expects to find the first instruction. In order to

RESET input to be effective, it must have a minimum duration of 2 machine

cycles. In other words, the high pulse must be high for a minimum of 2

machine cycles before it is allowed to go low.

EA

All the 8051 family members come with on-chip ROM to store programs. In

such cases, the EA pin is connected to the Vcc. For family members such as

8031 and 8032 in which there is no on-chip ROM, code is stored on an

external ROM and is fetched by the 8031/32. Therefore for the 8031 the EA

pin must be connected to ground to indicate that the code is stored

externally. EA, which stands for ―external access,‖ is pin number 31 in the

DIP packages. It is input pin and must be connected to either Vcc or GND.

In other words, it cannot be left unconnected.

PSEN

This is an output pin. PSEN stands for ―program store enable.‖ It is

the read strobe to external program memory. When the microcontroller is

executing from external memory, PSEN is activated twice each machine

cycle.

ALE

ALE (Address latch enable) is an output pin and is active high. When

connecting a microcontroller to external memory, potr 0 provides both

address and data. In other words the microcontroller multiplexes address and

data through port 0 to save pins. The ALE pin is used for de-multiplexing

the address and data by connecting to the G pin of the 74LS373 chip.




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I/O port pins and their functions

The four ports P0, P1, P2, and P3 each use 8 pins, making them

8-bit ports. All the ports upon RESET are configured as output, ready to be

used as output ports. To use any of these as input port, it must be

programmed.

Port 0

Port 0 occupies a total of 8 pins (pins 32 to 39). It can be used

for input or output. To use the pins of port 0 as both input and output

ports, each pin must be connected externally to a 10K-ohm pull-up

resistor. This is due to fact that port 0 is an open drain, unlike P1, P2

and P3. With external pull-up resistors connected upon reset, port 0 is

configured as output port. In order to make port 0 an input, the port

must be programmed by writing 1 to all the bits of it. Port 0 is also

designated as AD0-AD7, allowing it to be used for both data and

address. When connecting a microcontroller to an external memory,

port 0 provides both address and data. The microcontroller

multiplexes address and data through port 0 to save pins. ALE

indicates if P0 has address or data. When ALE=0, it provides data D0-

D7, but when ALE=1 it has address A0-A7. Therefore, ALE is used

for de-multiplexing address and data with the help of latch 74LS373.

Port 1

Port 1 occupies a total of 8 pins (pins 1 to 8). It can be used as

input or output. In contrast to port 0, this port does not require pull-up

resistors since it has already pull-up resistors internally. Upon reset,

port 1 is configures as an output port. Similar to port 0, port 1 can be

used as an input port by writing 1 to all its bits.




Page 29

Port 2


as input or output. Just like P1, port 2 does not need any pull-up

resistors since it has pull-up resistors internally. Upon reset port 2 is

configured as output port. To make port 2 input, it must be

programmed as such by writing 1s to it.

Port 3


as input or output. P3 does not need any pull-up resistors, the same as

P1 and P2 did not. Although port 3 is configured as output port upon

reset, this is not the way it is most commonly used. Port 3 has an

additional function of providing some extremely important signals

such as interrupts. Some of the alternate functions of P3 are listed

below:

P3.0 RXD (Serial input)

P3.1 TXD (Serial output)

P3.2 INT0 (External interrupt 0)

P3.3 INT1 (External interrupt 1)

P3.4 T0 (Timer 0 external input)

P3.5 T1 (Timer 1 external input)

P3.6 WR (External memory write strobe)

P3.7 RD (External memory read strobe)




Page 30

MODULE -2

LED INTERFACING

Like a normal diode, an LED consists of a chip of semiconducting material

impregnated, or doped, with impurities to create a p-n junction. As in other

diodes, current flows easily from the p-side, or anode, to the n-side, or

cathode, but not in the reverse direction. Charge-carriers—electrons and

holes—flow into the junction from electrodes with different voltages. When

an electron meets a hole, it falls into a lower energy level, and releases

energy in the form of a photon.

The wavelength of the light emitted, and therefore its color, depends on the

band gap energy of the materials forming the p-n junction. In silicon or

germanium diodes, the electrons and holes recombine by a non-radiative

transition which produces no optical emission, because these are indirect

band gap materials. The materials used for an LED have a direct band gap

with energies corresponding to near-infrared, visible or near-ultraviolet light.

LED development began with infrared and red devices made with gallium

arsenide. Advances in materials science have made possible the production

of devices with ever-shorter wavelengths, producing light in a variety of

colors.

LEDs are usually built on an n-type substrate, with an electrode attached to

the p-type layer deposited on its surface. P-type substrates, while less

common, occur as well. Many commercial LEDs, especially GaN/InGaN,

also use sapphire substrate. Substrates that are transparent to the emitted

wavelength, and backed by a reflective layer, increase the LED efficiency.

The refractive index of the package material should match the index of the

semiconductor, otherwise the produced light gets partially reflected back

into the semiconductor, where it may be absorbed and turned into additional

heat, thus lowering the efficiency. This type of reflection also occurs at the

surface of the package if the LED is coupled to a medium with a different

refractive index such as a glass fiber or air. The refractive index of most

LED semiconductors is quite high, so in almost all cases the LED is coupled

http://en.wikipedia.org/wiki/Diode

http://en.wikipedia.org/wiki/Doping_%28semiconductor%29

http://en.wikipedia.org/wiki/P-n_junction

http://en.wikipedia.org/wiki/Anode

http://en.wikipedia.org/wiki/Cathode

http://en.wikipedia.org/wiki/Electron

http://en.wikipedia.org/wiki/Electron_hole

http://en.wikipedia.org/wiki/Voltage

http://en.wikipedia.org/wiki/Energy_level

http://en.wikipedia.org/wiki/Energy

http://en.wikipedia.org/wiki/Photon

http://en.wikipedia.org/wiki/Wavelength

http://en.wikipedia.org/wiki/Band_gap

http://en.wikipedia.org/wiki/Silicon

http://en.wikipedia.org/wiki/Germanium

http://en.wikipedia.org/wiki/Indirect_band_gap

http://en.wikipedia.org/wiki/Indirect_band_gap

http://en.wikipedia.org/wiki/Direct_band_gap

http://en.wikipedia.org/wiki/Gallium_arsenide

http://en.wikipedia.org/wiki/Gallium_arsenide

http://en.wikipedia.org/wiki/Materials_science

http://en.wikipedia.org/wiki/Wavelength

http://en.wikipedia.org/wiki/Sapphire

http://en.wikipedia.org/wiki/Refractive_index




Page 31

into a much lower-index medium. The large index difference makes the

reflection quite substantial (per the Fresnel coefficients), and this is usually

one of the dominant causes of LED inefficiency. Often more than half of the

emitted light is reflected back at the LED-package and package-air

interfaces. The reflection is most commonly reduced by using a dome-

shaped (half-sphere) package with the diode in the center so that the

outgoing light rays strike the surface perpendicularly, at which angle the

reflection is minimized. An anti-reflection coating may be added as well.

The package may be cheap plastic, which may be colored, but this is only

for cosmetic reasons or to improve the contrast ratio; the color of the

packaging does not substantially affect the color of the light emitted. Other

strategies for reducing the impact of the interface reflections include

designing the LED to reabsorb and reemit the reflected light (called photon

recycling) and manipulating the microscopic structure of the surface to

reduce the reflectance, either by introducing random roughness or by

creating programmed moth eye surface patterns.

Conventional LEDs are made from a variety of inorganic semiconductor

materials, producing the following colors:

Aluminium gallium arsenide (AlGaAs) — red and infrared

Aluminium gallium phosphide (AlGaP) — green

Aluminium gallium indium phosphide (AlGaInP) — high-brightness

orange-red, orange, yellow, and green

Gallium arsenide phosphide (GaAsP) — red, orange-red, orange, and yellow

Gallium phosphide (GaP) — red, yellow and green

Gallium nitride (GaN) — green, pure green (or emerald green), and blue

also white (if it has an AlGaN Quantum Barrier)

Indium gallium nitride (InGaN) — near ultraviolet, bluish-green and blue

Silicon carbide (SiC) as substrate — blue

Silicon (Si) as substrate — blue (under development)

Sapphire (Al2O3) as substrate — blue

Zinc selenide (ZnSe) — blue

Diamond (C) — ultraviolet

Aluminium nitride (AlN), aluminium gallium nitride (AlGaN), aluminium

gallium indium nitride (AlGaInN) — near to far ultraviolet (down to

http://en.wikipedia.org/wiki/Fresnel_equations

http://en.wikipedia.org/wiki/Anti-reflection_coating

http://en.wikipedia.org/wiki/Semiconductor_materials

http://en.wikipedia.org/wiki/Semiconductor_materials

http://en.wikipedia.org/wiki/Aluminium_gallium_arsenide

http://en.wikipedia.org/wiki/Infrared

http://en.wikipedia.org/wiki/Aluminium_gallium_phosphide

http://en.wikipedia.org/wiki/Aluminium_gallium_indium_phosphide

http://en.wikipedia.org/wiki/Gallium_arsenide_phosphide

http://en.wikipedia.org/wiki/Orange_%28color%29

http://en.wikipedia.org/wiki/Yellow

http://en.wikipedia.org/wiki/Gallium_phosphide

http://en.wikipedia.org/wiki/Gallium_nitride

http://en.wikipedia.org/wiki/Blue

http://en.wikipedia.org/wiki/Indium_gallium_nitride

http://en.wikipedia.org/wiki/Silicon_carbide

http://en.wikipedia.org/wiki/Silicon

http://en.wikipedia.org/wiki/Sapphire

http://en.wikipedia.org/wiki/Zinc_selenide

http://en.wikipedia.org/wiki/Diamond

http://en.wikipedia.org/wiki/Aluminium_nitride

http://en.wikipedia.org/wiki/Aluminium_gallium_nitride

http://en.wikipedia.org/w/index.php?title=Aluminium_gallium_indium_nitride&action=edit

http://en.wikipedia.org/w/index.php?title=Aluminium_gallium_indium_nitride&action=edit

http://en.wikipedia.org/wiki/Ultraviolet




Page 32

210 nm) With this wide variety of colors, arrays of multicolor LEDs can be

designed to produce unconventional color patterns.

CIRCUIT Diagram

D3

LED

C?CAP NP

D7

LED

D4

LED

D5

LED

D8

LED

U?

AT89C52

91819 29

30

31

12345678

2122232425262728

1011121314151617

3938373635343332

RSTXTAL2XTAL1 PSEN

ALE/PROG

EA/VPP

P1.0/T2P1.1/T2-EXP1.2P1.3P1.4P1.5P1.6P1.7

P2.0/A8P2.1/A9

P2.2/A10P2.3/A11P2.4/A12P2.5/A13P2.6/A14P2.7/A15

P3.0/RXDP3.1/TXD

P3.2/INTOP3.3/INT1

P3.4/TOP3.5/T1

P3.6/WRP3.7/RD

P0.0/AD0P0.1/AD1P0.2/AD2P0.3/AD3P0.4/AD4P0.5/AD5P0.6/AD6P0.7/AD7

D1

LED

R1R

40

D2

LED

Y?

CRYSTAL

VCC

D6

LED

20




Page 33

FOUR ON FOUR OFF PATTERN

#include<reg51.h> // This file contains the Ports and SFR

address of 8051

#include<delay.h> // This file is used to produce seconds and

milliseconds delay

#define led P1 // 'P1' is given the another name as „led‟, u can use

'led' Or directly 'P1'

//for programming

void main() // main program starts from here

{

while (1) // Repeat forever

{

led=0xf0; // light on lower 4 leds '0'-> ON (11110000)

secdelay(1); // 1 secdelay

led=0x0f; // light on upper 4 leds '1'-> OFF (00001111)

secdelay (1);

}

}




Page 34

LEDS Programs

ON – OFF PATTERN

#include<reg51.h> //This file contains the Ports and SFR address of

8051

#include<delay.h> //This file is used to produce seconds and

milliseconds delay

#define led P1 // 'P1' is given the another name as 'led' ,u can use


//for programming


{

while(1) // Infinite Loop for infinite rotation

{

led=0x00; // light on All 8-leds '0'-> ON

secdelay(1); // 1 secdelay

led=0xff; // light OFF All 8-leds '1'-> OFF

secdelay(1);

}

}




Page 35

LEDS +SWITCHES

#include<reg51.h> //This file contains the Ports and SFR address

of 8051

#include<delay.h> //This file is used to produce seconds and

miliseconds delay

#define led P1 // 'P1' is given the another name as 'led' ,u can use


//for programming

sbit s1=P3^2; // define only single bit using sbit syntex

sbit s2=P3^3;

sbit s3=P3^4;


{

led=0xff;

while(1) // Infinite Loop for infinite rotation

{

if(s1==0)

{

led=0x00;

secdelay(1);




Page 36

led=0xff;

secdelay(1);

}

else if(s2==0)

{

led=0xf0;

secdelay(1);

led=0x0f;

secdelay(1);

}

else if(s3==0)

{

led=0xaa;

secdelay(1);

led=0x55;

secdelay(1);

}

else

{

led=0xff;

}

}

}




Page 37

MODULE -3

DC MOTOR

Circuit Diagram

Working Principle:

The principle upon which the d.c. motor works is very simple . If a

current carrying conductor is placed in a magnetic field,

mechanical force is experienced on the conductor, the direction of

which is given by the Fleming's left hand rule and hence the

1 2

VCC

Y1

GROUND

10UFU1

8051

31

19

18

9

12131415

12345678

3938373635343332

2122232425262728

1716

29

301110

40

20

EA/VP

X1

X2

RESET

INT0INT1T0T1

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

P2.0P2.1P2.2P2.3P2.4P2.5P2.6P2.7

RDWR

PSEN

ALE/PTXDRXD

VCC

VSS

SW1

RE

SE

T S

/W

12

VCC

C2

1 2

S3

10K

S11 2

S2

MG2

MOTOR DC

12

U5

UL2003

1

2

3

4

5

6

7

8 9

10

11

12

13

14

15

16IN1

IN2

IN3

IN4

IN5

IN6

IN7

GRD VCC

OUT7

OUT6

OUT5

OUT4

OUT3

OUT2

OUT1

DEVICE

K1

RELAY SPDT

35

412

C3

C

R2

RESISTOR SIP 10

123456789

10

33PF

CRYSTAL33PF

VCC

C1

R1




Page 38

conductor moves in the direction of force. The magnitude of the

mechanical force experienced on the conductor is given by:

F = B Ic Lc newtons

where B is the field strength in teslas ,

Ic is the current flowing through the conductor in amperes

and Lc is the length of the conductor in metres.

When the motor is connected to the d.c. supply mains a direct

current passes through the brushes and the

commutator to the armature winding ; while it passes through the

commutator it is converetd into a.c. so that the group of conductors

under successive field poles carry currrent in the opposite

direction. Also the direction of the currrent in the individual

conductors reverse as they pass away from the influence of one

pole to that of the next.

The split phase arrangement of the motor creates two fluxes B1and B2

which induces voltage around them in the rotor and under the influence of

these induced voltages current flows in the rotor. The current i1 produced by

flux B1 reacts with flux B2 and develops force F1.The quantities are going

to be expressed as :

B1=B1max . sin(wt)

B2=B2max . sin(wt + ß)

It may be assumed with negligible error thet the paths in which the

rotor current flow has negligible self-inductance and hence the

rotor currents are in phase with their respective voltages.

i1(db1/dt)=.B1max.cos wt

i2(db2/dt)=K. B2 max.cos (wt +X)

Since the two forces (f1and f2 ) developed are in opposition

.Therefore the net force F acting on the movable element is given

as:




Page 39

F=F2-F1(B2.i1-i2.b1)

F=K B1 max.B2 max sin r)

EMF Equation:

Back EMF, Eb=Flux *ZNP/60A

where

Z= total number of armature cunductors

N= Speed in r.p.m

P= total number of poles

A= Total number of parallel paths.

V= Eb + IaRa

Ia= (V - Eb)/Ra

where

V = Terminal voltage

Ia= Armature current

Ra= Armature resistance

Eb= back e.m.f.

Types of D.C. motor:

(i) Permanent magnet motors: It consists of an armature and one or

several permanent magnets encircling the armature . Field coils are

usually notrequired. However some of these motors do have coils

wound on the poles .

If they exist , these coils are intended only for recharging the

magnets in the event that they loose their strength.

(ii) Seperately excited D.C. motors: These motors have field coils




Page 40

similar to those of a shunt wound machine, but the armature and

field coils are fed from diferent supply sources and may have

different voltage ratings.

(iii) Series wound D.C. motor: As the name indicates, the field

coils,

consisting of few turns of a thick wire are connected in series with

the armature. The cross-sectional area of the wire used for the field

has to be fairly large to carry the armature current ,but owing to the

higher current , the number of turns of wire in them need not be

large.

(iv) Shunt wound D.C. motor: These motors are so named because

they basically operate with field coils connected in parallel with

the armature. The field winding consists of a large number of turns

of comparatively fine wire so as to provide large resistance. The

field current is much less than the armature current, sometimes as

low as 5%.

(v) Compound wound D.C. motor : A compound wound D.C.

motor has both shunt and series field coils. The shunt field is

normally stronger of the two. Compound wound motors are of two

types:.

(a) Cumalative compound wound motor.

(b) Differential compound wound motor.




Page 41

DC MOTOR PROGRAMS

Program for PWM

#include<reg51.h>

#include<delay.h>

sbit dc motor=P0^5; // define the motor using sbit as dc_motor

#define ON 1

#define OFF 0

void PWM(unsigned char Ton)

{

dc_motor=ON; // switch on the Dc motor for Ton

millisecond

ms_delay(Ton);

dc_motor=OFF; // switch oFF the Dc motor for (100-Ton)

millisecond

ms_delay(100-Ton);

}

void main()

{

while(1)

{

PWM(50);

}




Page 42

}

ON -OFF DC MOTOR

#include<reg51.h>

#include<delay.h>

/* define the motor using sbit as dc motor */

sbit dc_motor=P0^5;

#define ON 1

#define OFF 0

void main()

{

while(1)

{

dc_motor=ON; // switch on the Dc motor

secdelay(3);

dc_motor=OFF; // switch OFF the Dc motor

secdelay(2);

}

}




Page 43

MODULE -4

RELAY THE ELECTROMAGNETIC solenoid valve

Figure no 2.15: Electromagnetic Solenoid Valve

The electromagnetic relay consists of a multi-turn coil, wound on an iron core, to form an

electromagnet. When the coil is energised, by passing current through it, the core becomes

temporarily magnetised. The magnetised core attracts the iron armature. The armature is pivoted

which causes it to operate one or more sets of contacts.

When the coil is de-energised the armature and contacts are released. The coil can be

energised from a low power source such as a transistor while the contacts can switch high

powers such as the mains supply. The relay can also be situated remotely from the control

source. Relays can generate a very high voltage across the coil when switched off. This can

damage other components in the circuit. To prevent this a diode is connected across the coil.




Page 44

As there are always some chances of high voltage spikes back from the switching circuit i.e.

heater so an optocoupler/isolator MCT2e is used. It provides and electrical isolation between the

microcontroller and the heater. MCT2e is a 6-pin IC with a combination of optical transmitter

LED and an optical receiver as phototransistor. Microcontroller is connected to pin no 2 of

MCT2e through a 470-ohm resistor. Pin no.1 is given +5V supply and pin no.4 is grounded.

To handle the current drawn by the heater a power transistor BC-369 is used as a current driver.

Pin no.5 of optocoupler is connected to the base of transistor. It takes all it‘s output to Vcc and

activates the heater through relay circuit. The electromagnetic relay consists of a multi-turn coil,

wound on an iron core, to form an electromagnet. When the coil is energized, by passing current

through it, the core becomes temporarily magnetized. The magnetized core attracts the iron

armature. The armature is pivoted which causes it to operate one or more sets of contacts. When

the coil is de-energised the armature and contacts are released. Relays can generate a very high

voltage across the coil when switched off. This can damage other components in the circuit. To

prevent this a diode is connected across the coil. Relay has five points. Out of the 2 operating

points one is permanently connected to the ground and the other point is connected to the

collector side of the power transistor. When Vcc reaches the collector side i.e. signal is given to

the operating points the coil gets magnetized and attracts the iron armature. The iron plate moves

from normally connected (NC) position to normally open (NO) position. Thus the heater gets the

phase signal and is ON. To remove the base leakage voltage when no signal is present a 470-ohm

resistance is used.




Page 45

Circuit diagram

1 2

VCC

Y1

GROUND

10UFU1

8051

31

19

18

9

12131415

12345678

3938373635343332

2122232425262728

1716

29

301110

40

20

EA/VP

X1

X2

RESET

INT0INT1T0T1

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

P2.0P2.1P2.2P2.3P2.4P2.5P2.6P2.7

RDWR

PSEN

ALE/PTXDRXD

VCC

VSS

SW1

RE

SE

T S

/W

12

VCC

C2

1 2

S3

10K

S11 2

S2

MG2

MOTOR DC

12

U5

UL2003

1

2

3

4

5

6

7

8 9

10

11

12

13

14

15

16IN1

IN2

IN3

IN4

IN5

IN6

IN7

GRD VCC

OUT7

OUT6

OUT5

OUT4

OUT3

OUT2

OUT1

DEVICE

K1

RELAY SPDT

35

412

C3

C

R2

RESISTOR SIP 10

123456789

10

33PF

CRYSTAL33PF

VCC

C1

R1




Page 46

SIMPLE RELAY CONTROL

#include<reg51.h>

#include<delay.h>

sbit dev=P0^6; // define the 220v device using sbit as dev

#define ON 1

#define OFF 0

void main()

{

while(1)

{

dev=ON;

secdelay(5);

dev=OFF;

secdelay(3);

}

}




Page 47

RELAY CONTROL WITH TIME

#include<reg51.h>

#include<delay.h>

#define seg_port P2 // define segment port

sbit s1=P3^2; // define the switches using sbit as s1,s2,s3

sbit s2=P3^3;

sbit s3=P3^4;

sbit dev=P0^6;

#define delay 60

#define ON 1

#define OFF 0

// array is used to store the value of data to be sent on the port to

display

// any digit on seven segment as below

unsigned char

seg_array[10]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};

void main()

{

unsigned char maxlen=0;

while(1)

{

seg_port=seg_array[maxlen]; // show '0' on 7 segment

while(s3!=0) // while u not pressed switch s3

the statement in this




Page 48

{ //while loop

will execute

if(s1==0) // if u press s1

{

maxlen++; // then increment value of

maxlen by one

if(maxlen>9) // if maxlen is > 9 then store

'0' in maxlen

maxlen=0; //Note: The above step is

necessary because we can't

// show 2 digit value (ie. 10,11 etc

) on single 7 segment

ms_delay(223); // some delay for key

debouncing

}

else if(s2==0) // if u press s2

{

maxlen--; // then decrement maxlen by

one

if(maxlen==255) // if maxlen is equal to 255

then store '9' in maxlen

maxlen=9; // note :if u decrement an

unsigned char type variable

//when its value go below '0' the new

value 255 is stored in it

// so thats why the above step is

necessary

ms_delay(223);




Page 49

}

secdelay(1);

seg_port=seg_array[maxlen]; // send corresponding

data vale from array

// to segment port

}

secdelay(1);

while(maxlen<10)

{

seg_port=seg_array[maxlen];

secdelay(2);

maxlen++;

}

dev=ON;

secdelay(delay);

dev=OFF;

}}




Page 50

MODULE -5

STEPPER MOTOR Motion Control, in electronic terms, means to accurately control the movement of an object based

on either speed, distance, load, inertia or a combination of all these factors. There are numerous

types of motion control systems, including; Stepper Motor, Linear Step Motor, DC Brush,

Brushless, Servo, Brushless Servo and more.

A stepper motor is an electromechanical device which converts electrical pulses into discrete

mechanical movements. Stepper motor is a form of ac. motor .The shaft or spindle of a stepper

motor rotates in discrete step increments when electrical command pulses are applied to it in the

proper sequence. The motors rotation has several direct relationships to these applied input

pulses. The sequence of the applied pulses is directly related to the direction of motor shafts

rotation. The speed of the motor shafts rotation is directly related to the frequency of the input

pulses and the length of rotation is directly related to the number of input pulses applied [39].

For every input pulse, the motor shaft turns through a specified number of degrees, called

a step. Its working principle is one step rotation for one input pulse. The range of step size may

vary from 0.72 degree to 90 degree. In position control application, if the number of input pulses

sent to the motor is known, the actual position of the driven job can be obtained.

A stepper motor differs from a conventional motor (CM) as under:

a. Input to SM is in the form of electric pulses whereas input to a CM is invariably from a

constant voltage source.

b. A CM has a free running shaft whereas shaft of SM moves through angular steps.

c. In control system applications, no feedback loop is required when SM is used but a

feedback loop is required when CM is used.

d. A SM is a digital electromechanical device whereas a CM is an analog electromechanical

device [40].




Page 51

3.12.1Open Loop Operation

One of the most significant advantages of a stepper motor is its ability to be accurately controlled

in an open loop system. Open loop control means no feedback information about position is

needed. This type of control eliminates the need for expensive sensing and feedback devices such

as optical encoders. Control position is known simply by keeping track of the input step pulses

[39].

Every stepper motor has a permanent magnet rotor (shaft) surrounded by a stator. The

most common stepper motor has four stator windings that are paired with a center-tapped

common. This type of stepper motor is commonly referred to as a four- phase stepper motor. The

center tap allows a change of current direction in each of two coils when a winding is grounded,

thereby resulting in a polarity change of the stator. Notice that while a conventional motor shaft

runs freely, the stepper motor shaft moves in a fixed repeatable increment which allows one to

move it to a precise position. This repeatable




Page 52

Fig 3.20: Rotor Alignment

fixed movement is possible as a result of basic magnetic theory where poles of the Same polarity

repel and opposite poles attract. The direction of the rotation is dictated by the stator poles. The

stator poles are determined by the current sent through the wire coils. As the direction of the

current is changed, the polarity is also changed causing the reverse motion of the rotor. The

stepper motor used here has a total of 5 leads: 4 leads representing the four stator windings and 1




Page 53

common for the center tapped leads. As the sequence of power is applied to each stator winding,

the rotor will rotate. There are several widely used sequences where each has a different degree of

precision. Table shows the normal 4-step sequence. For clockwise go for step 1 to 4 & for counter

clockwise go for step 4 to 1.

Fig 3.21: Stator Windings Configuration

Step Winding A Winding B Winding C Winding D

1 0 1 1 1

2 1 0 1 1

3 1 1 0 1

4 1 1 1 0

Table 3.6: Input Sequence to the Windings

3.12.2 Step Angle & Steps per Revolution

Movement associated with a single step, depends on the internal construction of the motor, in

particular the number of teeth on the stator and the rotor. The step angle is the minimum degree

of rotation associated with a single step.

Step per revolution is the total number of steps needed to rotate one complete rotation or 360

degrees (e.g., 180 steps * 2 degree = 360) [31].

Winding D

Winding B

123

4 5 6

Winding DWinding C

Winding A




Page 54

Since the stepper motor is not ordinary motor and has four separate coils, which have to

be energized one by one in a stepwise fashion. We term them as coil A, B, C and D. At a

particular instant the coil A should get supply and then after some delay the coil B should get a

supply and then coil C and then coil D and so on the cycle continues. The more the delay is

introduced between the energizing of the coils the lesser is the speed of the stepper motor and

vice versa.




Page 55

Circuit diagram

R1

VCC

10K

Y1

33PF

VCC

S11 2

1 2

C1

U1

8051

31

19

18

9

12131415

12345678

3938373635343332

2122232425262728

1716

29

301110

40

20

EA/VP

X1

X2

RESET

INT0INT1T0T1

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

P2.0P2.1P2.2P2.3P2.4P2.5P2.6P2.7

RDWR

PSEN

ALE/PTXDRXD

VCC

VSS

CRYSTAL

S2

C2

VCC

33PF

MG1MOTOR STEPPER

123

4 5 6

1 2

C3

10UF

GROUND

S3

U5

UL2003

1

2

3

4

5

6

7

8 9

10

11

12

13

14

15

16IN1

IN2

IN3

IN4

IN5

IN6

IN7

GRD VCC

OUT7

OUT6

OUT5

OUT4

OUT3

OUT2

OUT1

C

R2

RESISTOR SIP 10

123456789

10

SW1

RE

SE

T S

/W

12




Page 56

DIRECTION CONTROL

#include<reg51.h>

#include<delay.h>

sbit m1=P0^0; // define the four windigs of stepper motor using sbit

as m1,m2,m3,m4 sbit m2=P0^1;

sbit m3=P0^2;

sbit m4=P0^3;

void mov_clk()

{

m1=1;m2=0;m3=0;m4=0; //give high pulse to m1 motor

moves one step angle in

// clockwise

ms_delay(200);


moves two step angle in

// clockwise

ms_delay(200);


moves three step angle in

// clockwise

ms_delay(200);


moves four step angle in // clockwise

ms_delay(200);

}

void mov_anticlk()

{




Page 57



// anti clockwise

ms_delay(200);

m1=0;m2=0;m3=1;m4=0;

ms_delay(200);

m1=0;m2=1;m3=0;m4=0;

ms_delay(200);

m1=1;m2=0;m3=0;m4=0;

ms_delay(200);

}

void motor_stop()

{

m1=0;m2=0;m3=0;m4=0;

}

void main()

{

while(1)

{

mov_clk(); // motor moves in clock wise

direction

motor_stop(); // motor stops

secdelay(2);

mov_anticlk(); // motor moves in anticlock wise

direction

motor_stop(); // motor stops




Page 58

secdelay(2);

}

}

DIRECTION CONTROL +SWITCHES

#include<reg51.h>

#include<delay.h>

sbit m1=P0^0; //define the four windigs of stepper motor using

sbit as m1,m2,m3,m4

sbit m2=P0^1;

sbit m3=P0^2;

sbit m4=P0^3;

sbit s1=P3^2; //define the switches using sbit as s1,s2,s3

sbit s2=P3^3;

sbit s3=P3^4;

void mov_clk()

{



// clockwise

ms_delay(200);


moves two step angle in

// clockwise

ms_delay(200);




Page 59


moves three step angle in //clockwise

ms_delay(200);


moves four step angle in

// clockwise

ms_delay(200);

}

void mov_anticlk()

{



//anti clockwise

ms_delay(200);

m1=0;m2=0;m3=1;m4=0;

ms_delay(200);

m1=0;m2=1;m3=0;m4=0;

ms_delay(200);

m1=1;m2=0;m3=0;m4=0;

ms_delay(200);

}

void motor_stop()

{

m1=0;m2=0;m3=0;m4=0;

}




Page 60

void main()

{

while(1)

{

if(s1==0)

{


direction

}

else if(s2==0)

{

mov_anticlk(); // motor moves in anticlock

wise direction

}

else if(s3==0)

{


direction

secdelay(1);

mov_anticlk(); // motor moves in anticlock

wise direction

secdelay(1);

}

else

{

motor_stop(); }}} // motor stops




Page 61

MODULE -6

Seven Segment

The seven-segment LED display has four individual digits, each with a

decimal point. Each of the seven segments (and the decimal point) in a given

digit contains an individual LED. When a suitable voltage is applied to a

given segment LED, current flows through and illuminates that segment

LED. By choosing which segments to illuminate, any of the nine digits can

be shown. For example, as shown in the figure below, a 2 can be displayed

by illuminating segments a, b, d, e, and g.

Seven segment displays come in two varieties - common anode (CA) and

common cathode (CC). In a CA display, the anodes for the seven segments

and the decimal point are joined into a single circuit node. To illuminate a

segment in a CA display, the voltage on a cathode must be at a suitably

lower voltage (about .7V) than the anode. In a CC display, the cathodes are

joined together, and the segments are illuminated by bringing the anode

voltage higher than the cathode node (again, by about .7V). The Digilab

board uses CA displays.




Page 62

The seven LEDs in each digit are labelled a-g. Since the Digilab board uses

CA displays, the anodes for each of the four digits are connected in a

common node, so that four separate anode circuit nodes exist (one per digit).

Similar cathode leads from each digit have also been tied together to form

seven common circuit nodes, so that one node exists for each segment type.

These four anode and seven cathode circuit nodes are available at the J2

connector pins labelled A1-A4 and CA-CG. With this scheme, any segment

of any digit can be driven individually. For example, to illuminate segments

b and c in the second digit, the b and c cathode nodes would be brought to a

suitable low voltage (by connecting the corresponding circuit node available

at the J2 connector to ground), and anode 2 would be brought to a suitable

high voltage (by connecting the corresponding circuit node available at the

J2 connector to Vdd).




Page 63

Circuit diagram

VCC

U2

7-segment

5 4 3 2 110

9876g f

vcc a b

hcvcc

de

10UF

LED3

SW1

RE

SE

T S

/W

12

1 2

LED7

LED4

C2

LED2

10K

1 2

U1

8051

31

19

18

9

12131415

12345678

3938373635343332

2122232425262728

1716

29

301110

40

20

EA/VP

X1

X2

RESET

INT0INT1T0T1

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

P2.0P2.1P2.2P2.3P2.4P2.5P2.6P2.7

RDWR

PSEN

ALE/PTXDRXD

VCC

VSS

S11 2

VCC

GROUND

CRYSTAL33PF

LED1

33PF

Y1

R2

470 E

S2

LED5

S3

VCC(5V)

C3

LED8

R1

C1

LED6




Page 64

UP COUNTER

#include<reg51.h>

#include<delay.h>

#define seg_port P2 //define segment port

// array is used to store the value of data to be sent on the port to display


unsigned char


void main()

{

unsigned char count;

while(1)

{

for(count=0;count<10;count++)

{

seg_port=seg_array[count]; // put array digit value from

array to the port

secdelay(1);

}

}

}




Page 65

DOWN COUNTER

#include<reg51.h>

#include<delay.h>

#define seg_port P2 // define segment port

// array is used to store the value of data to be sent on the port to display


unsigned char


void main()

{

char count;

while(1)

{

for(count=9;count>=0;count--)

{

seg_port=seg_array[count]; // send the corresponding value

of digit fom array to // port

secdelay(1);

}

}

}




Page 66

UP AND DOWN WITH SWITCH

#include<reg51.h>

#include<delay.h>

#define seg_port P2

sbit s1=P3^2; //define the switches using sbit as s1,s2,s3

sbit s2=P3^3;

sbit s3=P3^4;

// array is used to store the value of data to be sent on the port to

display


unsigned char


void main()

{

char maxlen=0,flag;

flag=0;

seg_port=seg_array[maxlen]; // show '0' on 7 segment

while(1)

{

while(s3!=0) // while u not pressed switch s3 the

statement in this

{ //while loop will

execute

if(s1==0) // if u press s1




Page 67

{

maxlen++; // then increment value of maxlen by one

if(maxlen>9) // if maxlen is > 9 then store '0' in maxlen

maxlen=0; // Note: The above step is necessary because we

can't show two digit

// value (ie. 10,11 etc

) on single 7 segment

flag=0; // reset flag ie flag=0

ms_delay(223); // some delay for key

debouncing

}

else if(s2==0) // if u press s2

{

maxlen--; // then decrement maxlen by

one

if(maxlen<0) // if maxlen is equal to 255

then store '9' in maxlen

maxlen=9;

flag=1; // set flag ie flag=1;

ms_delay(223);

}

secdelay(1);

seg_port=seg_array[maxlen]; // send corresponding

data vale from array

// to segment port




Page 68

}

secdelay(1);

if(flag==0) // if flag is reset (ie flag=0)

then increment value

{

while(maxlen<10)

{


secdelay(2);

maxlen++;

}

maxlen=9;flag=1;

}

else // if flag is set(ie flag=1) then

decrement value

{

while(maxlen>=0)

{


secdelay(2);

maxlen--;

} maxlen=0;flag=0;

}} }




Page 69

MODULE – 7

LCD

Liquid Crystal Display

3.2.12.1 LCD Display

Liquid crystal displays (LCD) are widely used in recent years as compares to LEDs. This is due

to the declining prices of LCD, the ability to display numbers, characters and graphics,

incorporation of a refreshing controller into the LCD, their by relieving the CPU of the task of

refreshing the LCD and also the ease of programming for characters and graphics. HD 44780

based LCDs are most commonly used.

LCD pin description

The LCD discuss in this section has the most common connector used for the Hitatchi 44780

based LCD is 14 pins in a row and modes of operation and how to program and interface with

microcontroller is describes in this section.

Fig 3.21 LCD Pin Description Diagram

VCC, VSS, VEE

Vcc

1615141312111098

654321

7

1615141312111098

654321

7

D7

E

Vcc

D4

ContrastRS

Gnd

R/W

Gnd

D0

D3

D6D5

13

2

D2D1




Page 70

The voltage VCC and VSS provided by +5V and ground respectively while VEE is used for

controlling LCD contrast. Variable voltage between Ground and Vcc is used to specify the

contrast (or "darkness") of the characters on the LCD screen.

RS (register select)

There are two important registers inside the LCD. The RS pin is used for their selection as

follows. If RS=0, the instruction command code register is selected, then allowing to user to send

a command such as clear display, cursor at home etc.. If RS=1, the data register is selected,

allowing the user to send data to be displayed on the LCD.

R/W (read/write)

The R/W (read/write) input allowing the user to write information from it. R/W=1, when it read

and R/W=0, when it writing.

EN (enable)

The enable pin is used by the LCD to latch information presented to its data pins. When data is

supplied to data pins, a high power, a high-to-low pulse must be applied to this pin in order to for

the LCD to latch in the data presented at the data pins.

D0-D7 (data lines)

The 8-bit data pins, D0-D7, are used to send information to the LCD or read the contents of the

LCD‘s internal registers. To displays the letters and numbers, we send ASCII codes for the letters

A-Z, a-z, and numbers 0-9 to these pins while making RS =1. There are also command codes that

can be sent to clear the display or force the cursor to the home position or blink the cursor.

We also use RS =0 to check the busy flag bit to see if the LCD is ready to receive the

information. The busy flag is D7 and can be read when R/W =1 and RS =0, as follows: if R/W =1

and RS =0, when D7 =1(busy flag =1), the LCD is busy taking care of internal operations and

will not accept any information. When D7 =0, the LCD is ready to receive new information.

CODES COMMAND TO LCD INSTRUCTION




Page 71

(HEX) Register

1 Clear display screen

2 Return home

4 Decrement cursor(shift cursor to left)

6 Increment cursor(shift cursor to right)

5 Shift display right

7 Shift display left

8 Display off, cursor off

A Display off, cursor on

C Display on, cursor off

E Display on, cursor blinking

F Display on, cursor blinking

10 Shift cursor position to left

14 Shift cursor position to right

18 Shift the entire display to the left

1C Shift the entire display to the right

80 Force cursor to beginning of 1st line

C0 Force cursor to beginning of 2nd line

38 2 line and 5x 7 matrix

LCD pin description




Page 72

Pin Symbol I/O Description

1 VSS - Ground

2 VCC - +5V power supply

3 VEE - Power supply to control contrast

4 RS I RS=0 to select command register, RS=1 to select data register.

5 R/W I R/W=0 for write, R/W=1 for read

6 E I/O Enable

7 PB0 I/O The 8 bit data bus

8 PB1 I/O The 8 bit data bus

9 DB2 I/O The 8 bit data bus









Page 73

Circuit diagram




Page 74

LCD FUNCTION

#include<reg51.h>

#include<delay.h>

#define DATA P1 // define DATA and Control Pins of LCD

sbit RS=P3^5;

sbit RW=P3^6;

sbit E=P3^7;

void lcd_cmd(unsigned char datax) // function to write command at

lcd port

{

ms_delay(20);

DATA=datax;

RS=0; //clear RS (ie. RS=0) to write command

RW=0; // write operation

E=1; // send H-L pulse at E pin

ms_delay(5);

E=0;

}

void lcd_data (unsigned char datax) // function to write data at lcd

port

{

ms_delay(20);

DATA=datax;




Page 75

RS=1; // set RS=1 to write DATA



ms_delay (5);

E=0;

}

void lcd_init() // function to initialize the LCD at

power on time

{

lcd_cmd(0x38); // 2x16 display select

ms_delay(3);

lcd_cmd (0x38); // 2x16 display select

ms_delay(3);

lcd_cmd (0x0c); // display on cursor off command

ms_delay(3);

lcd_cmd (0x06); // automatic cursor movement to

right

ms_delay(3);

lcd_cmd (0x01); // lcd clear command

ms_delay(3);

lcd_cmd (0x80); // first row first coloumn select

command

ms_delay(3);

}




Page 76

void lcd_puts(unsigned char *str) // function to display string to lcd

{

while(*str!='\0')

{

lcd_data(*str);

str++;

}

}

void displaypval(unsigned int datax) // function to display 3 digit

decimal value to lcd

{

unsigned int temp,temparr[3];

for(temp=3;temp>0;temp--)

{

temparr[temp-1]=datax%10;

datax=datax/10;

}

for(temp=0;temp<3;temp++)

{

lcd_data(temparr[temp]+48);

}

}

void main()




Page 77

{

lcd_init();

while(1)

{

lcd_cmd(0x80);

lcd_puts("Value");

lcd_cmd(0xc0);

displaypval(123);

}

}




Page 78

HOW TO DISPLAY CHARACTER

#include<reg51.h>

#include<delay.h>

#define DATA P1 // define DATA and Control

Pins of LCD

sbit RS=P3^5;

sbit RW=P3^6;

sbit E=P3^7;

void lcd_cmd(unsigned char datax) // function to write command

at lcd port

{

ms_delay(20);

DATA=datax;

RS=0; //clear RS (ie. RS=0) to write

command



ms_delay(5);

E=0;

}

void lcd_data (unsigned char datax) // function to write data at lcd

port

{

ms_delay(20);

DATA=datax;





Page 79



ms_delay (5);

E=0;

}

void lcd_init() // function to initialize the

lcd at power on time

{


ms_delay(3);


ms_delay(3);

lcd_cmd (0x0c); // display on cursor off

command

ms_delay(3);


right

ms_delay(3);


ms_delay(3);


command

ms_delay(3);

}

void main()




Page 80

{

lcd_init();

while(1)

{

lcd_cmd(0x80); // send address of 1st row ,1st col (0x80) as a

command to lcd

lcd_data('H'); // send data ('H') to lcd

lcd_data('E'); // send data ('E') to lcd

lcd_data('L'); // send data ('L') to lcd

lcd_data('L'); // send data ('L') to lcd

lcd_data('O'); // send data ('O') to lcd

}

}




Page 81

NUMBER DISPLAY

#include<reg51.h>

#include<delay.h>

#define DATA P1 // define DATA and Control Pins

of LCD

sbit RS=P3^5;

sbit RW=P3^6;

sbit E=P3^7;


lcd port

{

ms_delay(20);

DATA=datax;

RS=0; //clear RS (ie. RS=0) to write

command



ms_delay(5);

E=0;

}

void lcd_data (unsigned char datax) // function to write data at

lcd port

{

ms_delay(20);

DATA=datax;




Page 82



E=1; //send H-L pulse at E pin

ms_delay (5);

E=0;

}

void lcd_init() // function to initialize the LCD at

power on time

{


ms_delay(3);


ms_delay(3);

lcd_cmd (0x0c); // display on cursor off command

ms_delay(3);


right

ms_delay(3);


ms_delay(3);


command

ms_delay(3);

}

void main()




Page 83

{

unsigned char start_loc=0x80,count;

lcd_init();

while(1)

{

for(count=0;count<10;count++) // loop to count from 0 to 9

{

lcd_cmd(start_loc); // set start location as 0x80

lcd_data(count+48); // add 48 to the count to

convert it to ASCII value

secdelay(1); // wait for one second

start_loc++; // increment start location

if(start_loc==0x90) // if the cursor is at 17th

location

start_loc=0xc0; // change the location to 0xc0

(2nd row 1st column)

if(start_loc==0xd0) // if the cursor is at 33rd

location then

{

lcd_cmd(0x01); //clear lcd and

start_loc=0x80; // change the location to 0x80

(1st row 1st column)

}

}

} }




Page 84

A –Z DISPLAY

#include<reg51.h>

#include<delay.h>

#define DATA P1 // define DATA and Control Pins of LCD

sbit RS=P3^5;

sbit RW=P3^6;

sbit E=P3^7;


lcd port

{

ms_delay(20);

DATA=datax;

RS=0; //clear RS (ie. RS=0) to write command


E=1; //send H-L pulse at E pin

ms_delay(5);

E=0;

}

void lcd_data (unsigned char datax) // function to write data at

lcd port

{

ms_delay(20);

DATA=datax;





Page 85



ms_delay (5);

E=0;

}

void lcd_init() // function to initialize the lcd

at power on time

{


ms_delay(3);


ms_delay(3);

lcd_cmd (0x0c); // display on cursor off

command

ms_delay(3);


right

ms_delay(3);


ms_delay(3);

lcd_cmd (0x80); // first row first column select

command

ms_delay(3);

}

void main()




Page 86

{

unsigned char start_loc=0x80,count,ch;

lcd_init();

while(1)

{

ch=65; // ASCII value of 'A' is 65 (u can

also write ch='A')

for(count=0;count<26;count++) // loop to count from 0 to 26 as

A-Z total 26 character

{

lcd_cmd(start_loc); // set start location as 0x80

lcd_data(ch+count); // add to the count to convert

it to ASCII value

secdelay(1); // wait for one second

start_loc++; // increment start location

if(start_loc==0x90) // if the cursior is at 17th

location

start_loc=0xc0; // change the location to 0xc0

(2nd row 1st column)

if(start_loc==0xd0) // if the cursor is at 33rd

location then

{

lcd_cmd(0x01); //clear lcd and

start_loc=0x80; }}}}

// change the location to 0x80 (1st row 1st column)




Page 87

SOLDERING COMPONENTS INTO THE PCB

Bend the component leads at right angles with both bends at the same

distance apart as the PCB pad holes.

Ensure that both component leads and the copper PCB pads are clean

and free of oxidization.

Insert component leads into holes and bend leads at about 30 degrees

from vertical.

Using small angle cutters, cut the leads at about 0.1 - 0.2 of an inch

(about 2 - 4 mm) above copper pad.

Bring tinned soldering iron tip into contact with both the component

lead and the PCB pad. This ensures that both surfaces undergo the

same temperature rise.

Bring resin cored solder in contact with the lead and the copper

pad. Feed just enough solder to flow freely over the pad and the lead

without a ‗blobbing‘ effect. The final solder joint should be shiny and

concave indicating good ‗wetting‘ of both the copper pad and the

component lead. If a crack appears at the solder to metal interface

then the potential for forming a dry joint exists. If an unsatisfactory

joint is formed, suck all the solder off the joint using a solder sucker

or solder wick (braid) and start again.




Page 88

PRECAUTIONS

1. Mount the components at the approp places before soldering.

Follow the circuit discription and components details, leads

identification etc. Do not start soldering before making it confirm

that all the components are mounted at the right place.

2. Do not use a spread solder on the board, it may cause short circuit.

3. Do not sit under the fan while soldering.

4. Position the board so that gravity tends to keep the solder where

you want it.

5. Do not over heat the components at the board. Excess heat may

damage the components or board.

6. The board should not vibrate while soldering otherwise you have a

dry or a cold joint.

7. Do not put the kit under or over voltage source. Be sire about the

voltage either is d.c. or a.c. while operating the gadget.

8. Do spare the bare ends of the components leads otherwise it may

short circuit with the other components. To prevent this use sleeves

at the component leads or use sleeved wire for connections.

9. Do not use old dark colour solder. It may give dry joint. Be sure

that all the joints are clean and well shiny.

10. Do make loose wire connections specially with cell holder,

speaker, probes etc. Put knots while connections to the circuit

board, otherwise it may get loose.




Page 89




Page 90

OTHER

ELECTRONICS

COMPONENTS

USED




Page 91

RESISTOR

A resistor is an electrical component that limits or regulates the flow of

electrical current in an electronic circuit. Resistors can also be used to

provide a specific voltage for an active device such as a transistor.

All other factors being equal, in a direct-current (DC) circuit, the current

through a resistor is inversely proportional to its resistance, and directly

proportional to the voltage across it. This is the well-known Ohm's Law. In

alternating-current (AC) circuits, this rule also applies as long as the resistor

does not contain inductance or capacitance.

Resistors can be fabricated in a variety of ways. The most common type in

electronic devices and systems is the carbon-composition resistor. Fine

granulated carbon (graphite) is mixed with clay and hardened. The resistance

depends on the proportion of carbon to clay; the higher this ratio, the lower

the resistance.

Another type of resistor is made from winding Nichrome or similar wire on

an insulating form. This component, called a wirewound resistor, is able to

handle higher currents than a carbon-composition resistor of the same

physical size. However, because the wire is wound into a coil, the

component acts as an inductors as well as exhibiting resistance. This does

not affect performance in DC circuits, but can have an adverse effect in AC

circuits because inductance renders the device sensitive to changes in output.

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E u r e k a E m b e d d e d & A d v a n c e d S o f t w a r e T e c h n o l o g y ( E E A S T )

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RESISTOR COLOUR CODE



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CAPACITOR

A capacitor is a tool consisting of two conductive plates, each of which hosts an

opposite charge. These plates are separated by a dielectric or other form of

insulator, which helps them maintain an electric charge. There are several types of

insulators used in capacitors. Examples include ceramic, polyester, tantalum air,

and polystyrene. Other common capacitor insulators include air, paper, and plastic.

Each effectively prevents the plates from touching each other.

A capacitor is often used to store analogue signals and digital data. Another type of

capacitor is used in the telecommunications equipment industry. This type of

capacitor is able to adjust the frequency and tuning of telecommunications

equipment and is often referred to a variable capacitor. A capacitor is also ideal

for storing an electron. A capacitor cannot, however, make electrons.

SYMBOL

SYMBOL OF ELECTROLYTIC CAPACITOR

A capacitor measures in voltage, which differs on each of the two interior plates.

Both plates of the capacitor are charged, but the current flows in opposite

directions. A capacitor contains 1.5 volts, which is the same voltage found in a

common AA battery. As voltage is used in a capacitor, one of the two plates

becomes filled with a steady flow of current. At the same time, the current flows

away from the other plate.

To understand the flow of voltage in a capacitor, it is helpful to look at naturally

occurring examples. Lightning, for example, is similar to a capacitor. The cloud

represents one of the plates and the ground represents the other. The lightning is

the charging factor moving between the ground and the cloud.

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IMAGE OF ELECTROLYTIC CAPACITOR

UNPOLARISED CAPACITORS

A non-polarized ("non polar") capacitor is a type of capacitor that has no implicit

polarity -- it can be connected either way in a circuit. Ceramic, mica and some

electrolytic capacitors are non-polarized. You'll also sometimes hear people call

them "bipolar" capacitors.

SYMBOL OF NON POLARITY CAPACITOR

TRANSISTORS

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A Transistor is an semiconductor which is a fundamental component in almost

all electronic devices. Transistors are often said to be the most significant invention

of the 20th Century. Transistors have many uses including switching,

voltage/current regulation, and amplification - all of which are useful in renewable

energy applications.

A transistor controls a large electrical output signal with changes to a small input

signal. This is analogous to the small amount of effort required to open a tap

(faucet) to release a large flow of water. Since a large amount of current can be

controlled by a small amount of current, a transistor acts as an amplifier.

A transistor acts as a switch which can open and close many times per second.

Bipolar Junction Transistors

The most common type of transistor is a bipolar junction transistor. This is made

up of three layers of a semi-conductor material in a sandwich. In one configuration

the outer two layers have extra electrons, and the middle layer has electrons

missing (holes). In the other configuration the two outer layers have the holes and

the middle layer has the extra electrons.

SYMBOL OF NPN & PNP TRANSISTOR



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Layers with extra electrons are called N-Type, those with electrons missing called

P-Type. Therefore the bipolar junction transistors are more commonly known as

PNP transistors and NPN transistors respectively.

Bipolar junction transistors are typically made of silicon and so they are very

cheap to produce and purchase.

How do Transistors Work

A bipolar junction transistor has three terminals - Base, Collector, and Emitter

corresponding to the three semi-conductor layers of the transistor. The weak input

current is applied to the inner (base) layer. When there is a small change in the

current or voltage at the inner semiconductor layer (base), a rapid and far larger

change in current takes place throughout the whole transistor.



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Pictured above is a schematic diagram of the more common NPN transistor.

Below is an illustration of the same transistor using water rather than electricity to

illustrate the way it functions:

The illustration shows pipe work with three openings B (Base), C (Collector), and

E (Emitter). The reservoir of water at C is the supply voltage which is prevented

from getting though to E by a plunger. If water is poured into B, it pushes up the

plunger letting lots of water flow from C to E. If even more water is poured into B,

the plunger moves higher, and the flow of water from C to E increases.

Therefore, a small input current of electricity to the Base leads to a large flow of

electricity from the Collector to the Emitter.

Transistor Gain

Looking at the water analogy again, if it takes 1 litre of water per minute poured

into B to control 100 litres of water per minute flowing from C to E, then the Gain

(or amplification factor) is 100. A real transistor with a gain of 100 can control

100mA of current from C to E with an input current of just 1mA to the base (B).



Page 99

If the output power (current x voltage) are more than 1 Watt a Power Transistor

must be used. These let much more power flow through, and require a larger

controlling input current.

LDR

A Light Dependent Resistor (aka LDR, photoconductor, or photocell) is a device

which has a resistance which varies according to the amount of light falling on its

surface.

A typical light dependent resistor is pictured above together with (on the right hand

side) its circuit diagram symbol. Different LDR's have different specifications,

however the LDR's we sell in the REUK Shop are fairly standard and have a

resistance in total darkness of 1 MOhm, and a resistance of a couple of kOhm in

bright light (10-20kOhm @ 10 lux, 2-4kOhm @ 100 lux).

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Uses for Light Dependent Resistors

Light dependent resistors are a vital component in any electric circuit which is to

be turned on and off automatically according to the level of ambient light - for

example, solar powered garden lights, and night security lighting.

An LDR can even be used in a simple remote control circuit using the backlight

of a mobile phone to turn on a device - call the mobile from anywhere in the

world, it lights up the LDR, and lighting (or a garden sprinkler) can be turned on

remotely!

DIODES

A diode is the simplest sort of semiconductor device. Broadly speaking, a

semiconductor is a material with a varying ability to conduct electrical current.

Most semiconductors are made of a poor conductor that has had impurities (atoms

of another material) added to it. The process of adding impurities is called doping.

SYMBOL OF DIODE

Circuit Symbol

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IMAGE OF DIODES

In the case of LEDs, the conductor material is typically aluminum-gallium-

arsenide (AlGaAs). In pure aluminum-gallium-arsenide, all of the atoms bond

perfectly to their neighbors, leaving no free electrons (negatively-charged

particles) to conduct electric current. In doped material, additional atoms change

the balance, either adding free electrons or creating holes where electrons can go.

Either of these additions make the material more conductive.

A semiconductor with extra electrons is called N-type material, since it has extra

negatively-charged particles. In N-type material, free electrons move from a

negatively-charged area to a positively charged area.

A semiconductor with extra holes is called P-type material, since it effectively has

extra positively-charged particles. Electrons can jump from hole to hole, moving

from a negatively-charged area to a positively-charged area. As a result, the holes

themselves appear to move from a positively-charged area to a negatively-charged

area.

A diode comprises a section of N-type material bonded to a section of P-type

material, with electrodes on each end. This arrangement conducts electricity in

only one direction. When no voltage is applied to the diode, electrons from the N-

type material fill holes from the P-type material along the junction between the

layers, forming a depletion zone. In a depletion zone, the semiconductor material



Page 102

is returned to its original insulating state -- all of the holes are filled, so there are

no free electrons or empty spaces for electrons, and charge can't flow.

At the junction, free electrons from the N-type material fill holes

from the P-type material. This creates an insulating layer in the

middle of the diode called the depletion zone.

To get rid of the depletion zone, you have to get electrons moving from the N-type

area to the P-type area and holes moving in the reverse direction. To do this, you

connect the N-type side of the diode to the negative end of a circuit and the P-type

side to the positive end. The free electrons in the N-type material are repelled by

the negative electrode and drawn to the positive electrode. The holes in the P-type

material move the other way. When the voltage difference between the electrodes

is high enough, the electrons in the depletion zone are boosted out of their holes

and begin moving freely again. The depletion zone disappears, and charge moves

across the diode.



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When the negative end of the circuit is hooked up to the N-type layer and

the positive end is hooked up to P-type layer, electrons and holes start

moving and the depletion zone disappears.

If you try to run current the other way, with the P-type side connected to the

negative end of the circuit and the N-type side connected to the positive end,

current will not flow. The negative electrons in the N-type material are attracted to

the positive electrode. The positive holes in the P-type material are attracted to the

negative electrode. No current flows across the junction because the holes and the

electrons are each moving in the wrong direction. The depletion zone increases.

(See How Semiconductors Work for more information on the entire process.)

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When the positive end of the circuit is hooked up to the N-type layer

and the negative end is hooked up to the P-type layer, free electrons

collect on one end of the diode and holes collect on the other. The

depletion zone gets bigger.

DIODES CHARACTERISTICS



Page 105

LED

A light-emitting diode (LED) is a semiconductor device that emits visible light

when an electric current passes through it. The light is not particularly bright, but

in most LEDs it is monochromatic, occurring at a single wavelength. The output

from an LED can range from red (at a wavelength of approximately 700

nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR)

energy (830 nanometers or longer); such a device is known as an infrared-emitting diode (IRED).

An LED or IRED consists of two elements of processed material called P-type

semiconductors and N-type semiconductors. These two elements are placed in

direct contact, forming a region called the P-N junction. In this respect, the LED or

IRED resembles most other diode types, but there are important differences. The

LED or IRED has a transparent package, allowing visible or IR energy to pass

through. Also, the LED or IRED has a large PN-junction area whose shape is

tailored to the application.

SYMBOL OF LED

Circuit Symbol

Benefits of LEDs

Low power requirement: Most types can be operated with battery power

supplies.

High efficiency: Most of the power supplied to an LED or IRED is

converted into radiation in the desired form, with minimal heat production.

Long life: When properly installed, an LED or IRED can function for

decades.



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Typical Applications

Indicator lights: These can be two-state (i.e., on/off), bar-graph, or

alphabetic-numeric readouts.

LCD panel backlighting: Specialized white LEDs are used in flat-panel

computer displays.

Fiber optic data transmission: Ease of modulation allows wide

communications bandwidth with minimal noise, resulting in high speed and

accuracy.

Remote control: Most home-entertainment "remotes" use IREDs to

transmit data to the main unit.

optoisolator: Stages in an electronic system can be connected together

without unwanted interaction.

IMAGE OF DIFFERENT LED‟S







Page 107

Project Modules Detailed Cost Modules Component Quantity Cost

Power Supply

Transformer 1A 1 100

Transformer 500 mA 1 50

Power Cord 1 20

Diodes 4 8

LM7805 1 13

Capacitor 1000 uF 1 8

led 1 1

Resistance 470 ohm 1 0.25

MCU Module

40 Pin Base 1 7

MCU 1 70

Crystal 11.0592 1 9

Capacitor 22uF 1 6

Resistance 10 Kohm 1 0.25

Capacitor 33 pf 2 4

SIP 1 9

Push Button 1 3

LED Job 0

leds 8 8

Resisance 470 ohm 1 0.25

Switches 0

Push Button 3 9

Seven Segment Job 0

Seven Segment 1 17

Resistance 470 ohm 1 0.25

Base 28 Pin 1 6

DC Motor, Stepper Motor,Relay 0

ULN 2003 1 49

DC Motor 1 55

Stepper Motor 1 150

Base 16 Pin 1 4

Relay 1 25



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lamp Holder 1 10

lamp 1 0

LCD 0

LCD 1 150

16 Pin Connector 0

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