finger print based security system

Finger Print Based Security System

1. INTRODUCTION

1.1 Objective

Nowadays accurate personal identification is becoming more and more important. Usual

means (smart cards, passwords…) have shown their limits (falsification, loss…). Biometrics

(i.e. analysis of personal biological characteristics) can bring a satisfying answer to those

latter problems. Currently fingerprint recognition is the most widely used technique for

personal identification. Fingerprints are made up of locally parallel ridges with singular

points (minutiae), and they constitute a unique permanent universal pattern. The use of ink

and paper to get an image from a finger was used for a long time, but technological advances

have enabled to automate the acquisition stage by means of solid-state sensors. These sensors

exploit different techniques to acquire the image (pressure, electrical field, temperature…)

and require a static (matrix sensor) or mobile finger position (sweeping mode sensor).

Our project is developed to provide security for a Organization. In this project the

fingerprint sensor sense the thumb impression of the corresponding person and that image

will be compared with registered image, if the both images are unique, then the finger print

device activates particular task like access control to a secured area, identification of the

employee etc. The project contains 2 modes, the first one is master mode and the second is

user mode. The master mode is used to register the new user and gives the mode of

authorization. The master mode has the ability to create and delete the users. The user mode

is an ordinary mode used for the authentication of the employees. In user mode of

authorization, creation and deletion of a user cannot be performed.

The Master mode operations are done directly through interfacing the FM10 (Finger

Print Module) to the COM PORT of the computer. The application program is developed

using java API in Swings. The Java communication API is used for communicating with the

Fingerprint device. The employee details along with biometric information database is stored

in the flash memory of the Fingerprint module. The Microcontroller 89S52 is programmed to

operate under user mode. Microcontroller is programmed using C51 cross compiler.

Fingerprint image is scanned by the fingerprint device. If the scanned image matches with the

registered image then Microcontroller sends the authorized persons Id to the computer when

the person enters and leaves the organization. By this daily attendance of employees, many

employee records are maintained. The employee records are stored in the database.

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1.2 Principle of operation

When a finger is kept at the finger print reader, it will give the information

accordingly to microcontroller by sending appropriate commands to the reader and which is

displayed on the LCD. If the information matches with the one within the device then the DC

motor interfaced to the microcontroller responds accordingly. And if the information

provided by the user is incorrect or mismatch in finger prints is detected then access is

denied. Finger print reader and the microcontroller unit are connected using serial interface.

EmbeddedSystems

Embedded System is a combination of hardware and software used to achieve a single

specific task. An embedded system is a microcontroller-based, software driven, reliable, real-

time control system, autonomous, or human or network interactive, operating on diverse

physical variables and in diverse environments and sold into a competitive and cost conscious

market.

An embedded system is a special-purpose computer system designed to perform a

dedicated function. Unlike a general-purpose computer, such as a personal computer, an

embedded system performs one or a few pre-defined tasks, usually with very specific

requirements, and often includes task-specific hardware and mechanical parts not usually

found in a general-purpose computer. Since the system is dedicated to specific tasks, design

engineers can optimize it, reducing the size and cost of the product. Embedded systems are

often mass-produced, benefiting from economies of scale.

Physically, embedded systems range from portable devices such as digital watches and MP3

players, to large stationary installations like traffic lights, factory controllers, or the systems

controlling nuclear power plants. In terms of complexity embedded systems run from simple,

with a single microcontroller chip, to very complex with multiple units, peripherals and

networks mounted inside a large chassis or enclosure.

Mobile phones or handheld computers share some elements with embedded systems, such as

the operating systems and microprocessors which power them, but are not truly embedded

systems themselves because they tend to be more general purpose, allowing different

applications to be loaded and peripherals to be connected.





Examples of Embedded Systems

An embedded system typically has a specialized function with programs stored on

ROM. Examples of embedded systems are chips that monitor automobile functions, including

engine controls, antilock brakes, air bags, active suspension systems, environmental systems,

security systems, and entertainment systems. Everything needed for those functions is custom

designed into specific chips. No external operating system is required.

Network managers will need to manage more and more embedded systems devices,

ranging from printers to scanners, to handheld computing devices, to cell phones. All of these

have a need to connect with other devices, either directly or through a wireless or direct-

connect network. Most will have custom operating systems or variations of existing operating

systems (e.g., Microsoft Windows CE).

It's easy to picture nearly every electronic device as having an embedded system. For

example, refrigerators, washing machines, and even coffee brewers will benefit in some way

from embedded systems. A critical feature of an embedded system is its ability to

communicate, so embedded systems support Ethernet, Bluetooth (wireless), infrared, or other

technologies.

A weather station on top of a building may employ an embedded system that gathers

information from external sensors. This information can be pushed or pulled. In the push

scenario, the data is automatically sent to devices that have requested it. In the pull scenario,

users or network devices access the weather station to read the latest information.

Characteristics of Embedded System:

• An embedded system is any computer system hidden inside a product other than a

computer

• There will encounter a number of difficulties when writing embedded system

software in addition to those we encounter when we write applications

1. Throughput – Our system may need to handle a lot of data in a short period of

time.

2. Response–Our system may need to react to events quickly

3. Testability–Setting up equipment to test embedded software can be difficult





4. Debugability–Without a screen or a keyboard, finding out what the software is

doing wrong (other than not working) is a troublesome problem

5. Reliability – embedded systems must be able to handle any situation without

human intervention

6. Memory space – Memory is limited on embedded systems, and you must make

the software and the data fit into whatever memory exists

7. Program installation – you will need special tools to get your software into

embedded systems

8. Power consumption – Portable systems must run on battery power, and the

software in these systems must conserve power

9. Processor hogs – computing that requires large amounts of CPU time can

complicate the response problem

10. Cost – Reducing the cost of the hardware is a concern in many embedded system

projects; software often operates on hardware that is barely adequate for the job.

• Embedded systems have a microprocessor/ microcontroller and a memory. Some

have a serial port or a network connection. They usually do not have keyboards,

screens or disk drives.

1.3 Applications

Personal laptops and ATM

Door lock system and Safe box

Vehicles

Industry

2. BLOCK DIAGRAM AND DESCRIPTION





2.1 Block Diagram

Fig 2.1 Block Diagram

2.2Block DiagramDescription

The block diagram and its brief description are explained in block wise and this consists of

following blocks

MICROCONTROLLER

FINGERPRINT MODULE

RS-232 Cable, MAX-232.

LCD (LIQUID CRYSTAL DISPLAY)

POWER SUPPLY

DC MOTOR

Microcontroller AT89S52





The major heart of this project is at89s52 microcontroller, the reasons why we selected this in

our project?,. The AT89S52 provides the following standard features: 8K bytes of Flash, 256

bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a

six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and

clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to

zero frequency and supports two software selectable power saving modes. The Idle Mode

stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to

continue functioning. The Power-down mode saves the RAM con-tents but freezes the

oscillator, disabling all other chip functions until the next interrupt or hardware reset.

Fingerprint module

Fingerprint module consists of f fingerprint sensor and scanning section.A fingerprint

pattern is composed of a sequence of ridges and valleys. In afingerprint image, the ridges

appear as dark lines while the valleys are the light areasbetween the ridges. A cut or burn to a

finger does not affect the underlying ridgestructure, and the original pattern will be

reproduced when new skin grows. Ridges andvalleys generally run parallel to each other, and

their patterns can be analyzed on aglobal and local level.Ridges and valleys generally run

parallel to each other, and their patterns can beanalyzed on a global and local level.

LCDModule

A liquid crystal is a material (normally organic for LCDs) that will flow like a liquid

but whose molecular structure has some properties normally associated with solids. The

Liquid Crystal Display (LCD) is a low power device. The power requirement is typically in

the order of microwatts for the LCD. However, an LCD requires an external or internal light

source. It is limited to a temperature range of about 0C to 60C and lifetime is an area of

concern, because LCDs can chemically degrade

There are two major types of LCDs which are:

1. Dynamic-scattering LCDs

2. Field-effect LCDs





Field-effect LCDs are normally used in such applications where source of energy is a prime

factor (e.g., watches, portable instrumentation etc.).They absorb considerably less power than

the light-scattering type. However, the cost for field-effect units is typically higher, and their

hoight is limited to 2 inches. On the other hand, light-scattering units are available up to 8

inches in height. Field-effect LCD is used in the project for displaying the appropriate

information.

The turn-on and turn-off time is an important consideration in all displays. The response time

of LCDs is in the range of 100 to 300ms.The lifetime of LCDs is steadily increasing beyond

10,000+hours limit. Since the color generated by LCD units is dependent on the source of

illumination, there is a wide range of color choice.

Power supply

The Entire Project needs power for its operation. However, from the study of this

project it comes to know that we supposed to design 5v and 12v dc power supply. So by

utilizing the following power supply components, required power has been gained. (230/12v

(1A and 500mA) – Step down transformers, Bridge rectifier to converter ac to dc, booster

capacitor and +5v (7805) and +12v (7812) regulator to maintain constant 5v & 12 supply for

the controller circuit and Fingerprint module).

DC Motors

In this project DC motors can be used to drive the gates. There are always two

options in front of thedesigner whether to use a DC motor or a stepper motor. When it comes

to speed, weight, size,cost... DC motors are always preferred over stepper motors. There are

many things which youcan do with your DC motor when interfaced with a microcontroller.

For example you cancontrol the speed of motor; you can control the direction of rotation.In

this part of tutorial we will learn to interface and control of a DC motor with

amicrocontroller. Usually H‐bridge is preferred way of interfacing a DC motor. These days

manyIC manufacturers have H‐bridge motor driver available in the market like L293D is

most used HBridgedriver IC. H‐bridge can also be made with the help of transistors and

MOSFETs etc.rather of being cheap, they only increase the size of the design board, which is

sometimes notrequired so using a small 16 pin IC is preferred for this purpose.

3. FINGERPRINT MODULE





3.1 Introduction

In the 21st century the use of biometric based systems have seen an

exponentialgrowth. This is all because of tremendous progress in this field making it possible

tobring down their prices, easiness of use and its diversified use in every day life.Biometrics

is becoming new state of art method of security systems. Biometrics areused to prevent

unauthorized access to ATM, cellular phones , laptops , offices, carsand many other security

concerned things. Biometric have brought significant changesin security systems making

them more secure then before, efficient and cheap. Theyhave changed the security system

from what you remember (such as password) orwhat you possess (such as car keys) to

something you embody (retinal patterns,fingerprints, voice recognition).

What is biometrics?

Biometrics is the science of verifying the identity of an individual throughphysiological

measurements or behavioral traits. Since biometric identifiers are associated permanently

with the user they are more reliable than token or knowledge based authentication methods.

Advantages of Biometrics

Biometrics offers several advantages over traditional security measures. Some of

them are presented below.

1. Accuracy and Security

Biometrics based security systems are far most secure and accurate thantraditional

password or token based security systems. For example a password basedsecurity system has

always the threat of being stolen and accessed by the unauthorized user. Further more the

traditional security systems are always prone to accuracy ascompared to biometrics which is

more accurate.

2.One individual, Multiple IDs

Traditional security systems face the problem that they don’t give solution to

theproblem of individuals having multiple IDs. For examples a person having

multiplepassports to enter a foreign country. Thanks to biometrics!!! They give us a system

inwhich an individual can’t possess multiple IDs and can’t change his ID through out hislife

time. Each individual is identified through a unique Biometric identity throughout theworld.

3. One ID, multiple individuals





In traditional security systems one ID can be used by multiple individuals.

Forexample in case of a password based security system a single password can be

sharedamong multiple individuals and they can share the resources allotted to a

singleindividual. Biometric based security system doesn’t allow such a crime. Here

eachindividual has a single unique ID and it can’t be shared with any other individual.

Biometrics categories

Biometrics can be categorized in various categories as follow.

1.Physical biometrics

2.Behavioral biometrics

Physical biometrics

This biometrics involves measurement of physical characteristics of individuals.The

most prominent of these include

Fingerprints

Face

Hand geometry

Iris scans

Behavioral biometrics

This category of biometrics is temporal in nature. They are evolved duringthe life

time of an individual. It involves measuring the way in which an individual performscertain

tasks. Behavioral biometrics include

Gait

Handwriting

Speech

Signature

3.2History of Fingerprint





Fingerprints have been scientifically studied for many years in our society.

Thecharacteristics of fingerprints were studied as early as 1600s. Meanwhile, using

fingerprints as a means of identification first occurred in the mid-1800s. Sir WilliamHerschel,

in 1859, discovered that fingerprints do not change over time and that eachpattern is unique

to an individual. With these findings, he was the first to implement asystem using fingerprints

and handprints to identify an individual in 1877. By 1896,police forces in India realized the

benefit of using fingerprints to identify criminals, andthey began collecting the fingerprints of

prisoners along with their other measurements

With a growing database of fingerprint images, it soon became desirable to havean

efficient manner of classifying the various images. Between 1896 and 1897, SirEdward

Henry developed the Henry Classification System, which quickly foundworldwide

acceptance within a few years. This system allows for logical categorizationof a complete set

of the ten fingerprint images for a person. By establishing groupingsbased on fingerprint

pattern types, the Henry System greatly reduces the effort ofsearching a large database. Until

the mid-1990s, many organizations continued to usethe Henry Classification System to store

their physical files of fingerprint images.

As fingerprints began to be utilized in more fields, the number of requests

forfingerprint matching began to increase on a daily basis. At the same time, the size ofthe

databases continued to expand with each passing day. Therefore, it soon becamedifficult for

teams of fingerprint experts to provide accurate results in a timely manner. Inthe early 1960s,

the FBI, Home Office in the United Kingdom, and Paris PoliceDepartment began to devote a

large amount of resources in developing automaticfingerprint identification systems. These

systems allowed for an improvement inoperational productivity among law enforcement

agencies. At the same time, theautomated systems reduced funding requirements to hire and

train human fingerprintexperts. Today, automatic fingerprint recognition technology can be

found in a widerange of civilian applications.

What is A Fingerprint ?

A fingerprintis the feature pattern of one finger. It is believed with strongevidences

that each fingerprint is unique. Each person has his ownfingerprints with the permanent

uniqueness. So fingerprints have being usedfor identification and forensic investigation for a

long time. Fingerprintrecognitionis one of the most reliable identification





techniques.Fingerprint technologyis the most widely used for security purposes.

TheTechnology is being frequently used in criminal investigation purpose.

Figure 3.2 Fingerprint image acquired by an Optical Sensor.

3.3 Fingerprint features

A fingerprint pattern is composed of a sequence of ridges and valleys. In afingerprint

image, the ridges appear as dark lines while the valleys are the light areasbetween the ridges.

A cut or burn to a finger does not affect the underlying ridgestructure, and the original pattern

will be reproduced when new skin grows. Ridges andvalleys generally run parallel to each

other, and their patterns can be analyzed on aglobal and local level.Ridges and valleys

generally run parallel to each other, and their patterns can beanalyzed on a global and local

level.

Depending on the application, fingerprint based systems can be used in one of two modes

1) Master Mode (enrollment, deletion…..).

2) User Mode (Verification or identification).

1. Master Mode (Enrollment, Deletion):

Enrollment is done in this mode. In this mode fingerprint image is captured by a

scanner, enhanced, encoded, and stored as a reference template for future comparisons. How

fingerprint systems extract features and encode and store information in the template is based

on the system vendor’s proprietary algorithms. Template size varies depending on the vendor

and the technology. Templates can be stored remotely in a central database or within the





device itself. The reference template is linked to the identity specified on the identification

document. This reference template linked to the corresponding identity is later used for the

authentication purpose. Deletion of the enrolled users is also done in this mode.

Figure3.3.1Master Mode Block Diagram

The registration of the employees is done directly through interfacing the FM10 (Finger Print

Module) to the computer in the master mode. The application program is developed using

java API. The Java communication API is used to communicate with the fingerprint device

by which registration process can be done. The employee details along with biometric

information database are stored in the flash memory of the Fingerprint module. The flash

memory can store 100 users of data. The fingerprint image is scanned twice for each user and

the corresponding two images along with the user ID and password are stored in the flash

memory.

2. User Mode (Verification or Identification)

In this mode, the step after enrollment is to verify that a person is who he or she claims to be

(i.e., the person who enrolled). After the individual provides the fingerprint he or she enrolled

with, which the fingerprint system captures, generating a trial template that is based on the

vendor’s algorithm. The system then compares the trial biometric template with this person’s

reference template, which was stored in the system during enrollment, to determine whether

the individual’s trial and stored templates match (see figure 1).





Figure 3.3.2User Mode Block diagram

Microcontroller 89S52 is programmed to operate under user mode. The microcontroller is

interfaced with Fingerprint sensor, Computer, Infrared sensors, Keyboard, LCD display,

Relays, Door Activators. Important sections involved in the user mode:

Fingerprint Scanning section.

Microcontroller section.

LIQUID CRYSTAL DISPLAY Section.

Microcontroller-computer Interface Section.

Relay section.

3.4 Fingerprint Scanning section


FINGER PRINT SENSOR

L.C.D

FINGER PRINT

MODULE

MICRO CONTROLLER

89S52

MAX232

ULN 2003




NITIGENFIM10 a stand-alone Fingerprint Recognition Device is used for scanning

the finger fingerprint image. It provides the high recognition performance, the low power

dissipation and the RS-232 serial interface with the simple protocol for easy integration into a

wide range of applications. It has ain built Flash Memory which has a capacity of storing 100

users. The Fingerprint sensor is scans the Fingerprint and convert that Fingerprint image to

an equivalent 16 byte template. For each user two Fingerprint images each of size 16 bytes,

ID (10 bytes), Password (16 bytes) is stored in the Flash Memory.

In this user mode this FIM10(Fingerprint Device) is interfaced with the

Microcontroller 89S52. Before entering an organization the employee provides his ID and

fingerprint device is used to scan the fingerprint of he or she enrolled with, generating a trial

template. The device then compares the trial fingerprint template with this person’s reference

template, which was stored in the device memory during enrollment, to determine whether

the employee trial and stored templates match. This information is reported to the

Microcontroller. The Microcontroller is programmed to do necessary tasks.

Position of the fingerprint

In order to capture the most minutiae, maximize the surface area of the fingerprint on

thefingerprint input window.

Figure shows the correct positioning of the fingerprint on the input window.

Figure 3.4.1Correct positioning of fingerprint on input window





Figure Common mistakes

Allowable angle of fingerprint rotation

FIM10 allows up to 45 degrees for input fingerprint rotation, as illustrated in Figure.

Figure 3.4.2The allowable angle of fingerprint rotation.

Fingerprint Recognition

Our fingerprint recognition system is ultimately based on a welldefined representation

of a fingerprint recognition Technique.Taking a Fingerprint at first we enhanced the quality

of that image to make the imageclearer for easy further operations. Since the fingerprint

images acquired fromsensors or other medias are not assured with perfect quality,

thoseenhancement methods, for increasing the contrast between ridges andfurrows and for

connecting the false broken points of ridges due to insufficientamount of ink, are very useful

for keep a higher accuracy to fingerprint recognition. various methods that are adopted in our

fingerprint recognition system to enhance the image quality are Fingerprint Enhancement

byHistogram Equalization and Fingerprint Enhancement by FourierTransform.

The fingerprint recognition problem can be grouped into twosub-domains: one is

fingerprint verification and the other is fingerprintidentification. Fingerprint verification is to

verify the authenticity of oneperson by his fingerprint. The user provides his fingerprint





together with hisidentity information like his ID number. The fingerprint verification

systemretrieves the fingerprint template according to the ID number and matchesthe template

with the real-time acquired fingerprint from the user. Usually itis the underlying design

principle of AFAS (Automatic FingerprintAuthentication System).Fingerprint identification

is to specify one person’sidentity by his fingerprint(s). Without knowledge of the person’s

identity, thefingerprint identification system tries to match his fingerprint(s) with those inthe

whole fingerprint database. It is especially useful for criminal investigationcases. And it is the

design principle of AFIS (Automatic FingerprintIdentification System). However, all

fingerprint recognition problems, eitherverification or identification, are ultimately based on a

well-definedrepresentation of a fingerprint. As long as the representation of

fingerprintsremains the uniqueness and keeps simple, the fingerprint matching, either forthe

1-to-1 verification case or 1-to-m identification case, is straightforward andeasy.

FIM30N

FIM30N is a low-price stand-alone Fingerprint Identification Device with many

excellentfeatures. It provides benefits such as high identification performance, low

powerconsumption and RS-232 serial interface with the various commands for easy

integrationinto a wide range of applications. It is a durable and compact device with

fingerprintidentification module containing NITGEN® optics-based fingerprint sensor inside.

Target Application

1. Door-lock system

2. Safe Box

3. Simple Access Controller

4. Vehicle Control

5. ATM , POS

6. And more





Basic Feature

Hardware Specification

Table 3.4.1Hardware specification of FIM3030

Operation Specification

Table 3.4.2Operational specification of FIM3030

Verification systems can contain databases ranging from dozens to millions of

enrolledtemplates but are always predicated on matching an individual’s presented fingerprint

against his or her reference template. Nearly all verification systems can render a match–no-

match decision in less than a second. A system that requires employees to authenticate their





claimed identities before granting them access to secure buildings or to computers is a

verification application. In this mode creation and deletion of users is not possible.

Our project is developed to provide security to an Organization. In this project NITIGEN

fingerprint sensor is used to scan the fingerprint image. The registration of the employees is

done directly through interfacing the FM10 (Fingerprint Module) to the computer in the

master mode. The application program is developed using java API. The employee details

along with biometric information database is stored in the flash memory of the Fingerprint

Module. The Microcontroller 89S52 is programmed to operate under user mode.

Figure 3.4.4 The Fingerprint Verification Process

4.MICROCONTROLLER





4.1 Introduction to Microcontroller

A microcontroller (or MCU) is a computer-on-a-chip. It is a type of microprocessor

emphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purpose

microprocessor (the kind used in a PC).

Typical Microcontroller Architecture and Features

The basic internal designs of microcontrollers are pretty similar. Figure1 shows the block

diagram of a typical microcontroller. All components are connected via an internal bus and

are all integrated on one chip. The modules are connected to the outside world via I/O pins.

Figure 4.1 Basic Layout of Microcontroller

The following list contains the modules typically found in a microcontroller. You can find a

more detailed description of these components in later sections.

Processor Core

The CPU of the controller. It contains the arithmetic logic unit, the control unit, and the

registers (stack pointer, program counter, accumulator register, register file . . .).

Memory





The memory is sometimes split into program memory and data memory. In larger controllers,

a DMA controller handles data transfers between peripheral components and the memory.

Interrupt Controller

Interrupts are useful for interrupting the normal program flow in case of (important) external

or internal events. In conjunction with sleep modes, they help to conserve power.

Timer/Counter

Most controllers have at least one and more likely 2-3 Timer/Counters, which can be used to

timestamp events, measure intervals, or count events. Many controllers also contain PWM

(pulse width modulation) outputs, which can be used to drive motors or for safe breaking

(antilock brake system, ABS). Furthermore the PWM output can, in conjunction with an

external filter, be used to realize a cheap digital/analog converter.

Digital I/O

Parallel digital I/O ports are one of the main features of microcontrollers. The number of I/O

pins varies from 3-4 to over 90, depending on the controller family and the controller type.

Analog I/O

Apart from a few small controllers, most microcontrollers have integrated analog/digital

converters, which differ in the number of channels (2-16) and their resolution (8-12 bits). The

analog module also generally features an analog comparator. In some cases, the

microcontroller includes digital/analog converters.

The UART: What it is and how it works

The Universal Asynchronous Receiver/Transmitter (UART) controller is the key component

of the serial communications subsystem of a computer. The UART takes bytes of data and

transmits the individual bits in a sequential fashion. At the destination, a second UART re-

assembles the bits into complete bytesSerial transmission is commonly used with modems

and for non-networked communication between computers, terminals and other devices.

There are two primary forms of serial transmission: Synchronous and Asynchronous.

Depending on the modes that are supported by the hardware, the name of the communication





sub-system will usually include aA if it supports Asynchronous communications, and a S if it

supports Synchronous communications. Both forms are described below.

Synchronous Serial Transmission

Synchronous serial transmission requires that the sender and receiver share a clock with one

another, or that the sender provide a strobe or other timing signal so that the receiver knows

when to “read” the next bit of the data. In most forms of serial Synchronous communication,

if there is no data available at a given instant to transmit, a fill character must be sent instead

so that data is always being transmitted. Synchronous communication is usually more

efficient because only data bits are transmitted between sender and receiver, and synchronous

communication can be more costly if extra wiring and circuits are required to share a clock

signal between the sender and receiver.

A form of Synchronous transmission is used with printers and fixed disk devices in that the

data is sent on one set of wires while a clock or strobe is sent on a different wire. Printers and

fixed disk devices are not normally serial devices because most fixed disk interface standards

send an entire word of data for each clock or strobe signal by using a separate wire for each

bit of the word. In the PC industry, these are known as Parallel devices.

The standard serial communications hardware in the PC does not support Synchronous

operations. This mode is described here for comparison purposes only

Asynchronous Serial Transmission

Asynchronous transmission allows data to be transmitted without the sender having to

send a clock signal to the receiver. Instead, the sender and receiver must agree on timing

parameters in advance and special bits are added to each word which are used to synchronize

the sending and receiving units.

When a word is given to the UART for Asynchronous transmissions, a bit called the

"Start Bit" is added to the beginning of each word that is to be transmitted. The Start Bit is

used to alert the receiver that a word of data is about to be sent, and to force the clock in the

receiver into synchronization with the clock in the transmitter. These two clocks must be

accurate enough to not have the frequency drift by more than 10% during the transmission of





the remaining bits in the word. (This requirement was set in the days of mechanical

teleprinters and is easily met by modern electronic equipment.)

After the Start Bit, the individual bits of the word of data are sent, with the Least

Significant Bit (LSB) being sent first. Each bit in the transmission is transmitted for exactly

the same amount of time as all of the other bits, and the receiver “looks” at the wire at

approximately halfway through the period assigned to each bit to determine if the bit is a 1 or

a 0. For example, if it takes two seconds to send each bit, the receiver will examine the signal

to determine if it is a 1 or a 0 after one second has passed, then it will wait two seconds and

then examine the value of the next bit, and so on.

The sender does not know when the receiver has “looked” at the value of the bit. The

sender only knows when the clock says to begin transmitting the next bit of the word.When

the entire data word has been sent, the transmitter may add a Parity Bit that the transmitter

generates. The Parity Bit may be used by the receiver to perform simple error checking. Then

at least one Stop Bit is sent by the transmitter.

When the receiver has received all of the bits in the data word, it may check for the Parity

Bits (both sender and receiver must agree on whether a Parity Bit is to be used), and then the

receiver looks for a Stop Bit.

If the Stop Bit does not appear when it is supposed to, the UART considers the entire

word to be garbled and will report a Framing Error to the host processor when the data word

is read. The usual cause of a Framing Error is that the sender and receiver clocks were not

running at the same speed, or that the signal was interrupted.

Regardless of whether the data was received correctly or not, the UART automatically

discards the Start, Parity and Stop bits. If the sender and receiver are configured identically,

these bits are not passed to the host.If another word is ready for transmission, the Start Bit for

the new word can be sent as soon as the Stop Bit for the previous word has been sent.

4.2 AT89S52MICROCONTROLLER

Description





The AT89s52 is a low power, high performance CMOS 8-bit micro computer with 8K

bytes of flash programmable and erasable read only memory(PEROM).The device is

manufactured using Atmel’s high density nonvolatile memory technology and is

compatible with the industry standard 80c51 and 80C52 instruction set and pin out. The on-

chip flash allows the program memory to be reprogrammed in-system or by a conventional

nonvolatile memory programmer. By combining a versatile 8-bit CPU with flash on a

monolithic chip, the Atmel AT89s52 Is a powerful microcomputer which provides a highly

flexible and cost effective solution to many embedded control applications. The main

advantages of 89s52 over 8051 are

Software Compatibility

Program Compatibility

Rewritability

The 89s52 microcontroller has an excellent software compatability, i.e. the software used

can be applicable to any other microcontroller. The program written on this microcontroller

can be carried to any base.

Program compatibility is the major advantage in 89s52. The program can be used in any

other advanced microcontroller. The program can be reloaded and changed for nearly 1000

times.

Features

• Compatible with MCS-51® Products

• 8K Bytes of In-System Programmable (ISP) Flash Memory

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Three 16-bit Timer/Counters





• Eight Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

• Dual Data Pointer

• Power-off Flag

89S52 Processor Architecture

The AT89s52 provides the following standard features: 8K bytes of Flash, 256 bytes

of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level interrupt

architecture, a full-duplex serial port, on-chip oscillator, and clock circuitry. In addition, the

AT89s52 is designed with static logic for operation down to zero frequency and supports two

software selectable power saving modes. The Idle Mode stops the CPU while allowing the

RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-

down mode saves the RAM contents but freezes the oscillator, disabling all other chip

functions until the next hardware reset.





Figure 4.2.1 89S52 microcontroller architecture





Pin Diagram

Figure 4.2.2 Pin diagram of 89S52

Pin Description

VCC

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

GND

Pin 20 provides ground.





Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can

sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high

impedance inputs.

Port 0 can also be configured to be the multiplexed low order address/data bus during

accesses to external program and data memory. In this mode, P0 has internal pull ups.

Port 0 also receives the code bytes during Flash programming and outputs the code

bytes during program verification. External pull ups are required during program verification.

Port 1

Port 1 is an 8-bit bidirectional I/O port with internal pull ups. The Port 1 output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled

high by the internal pull ups and can be used as inputs. As inputs, Port 1 pins that are

externally being pulled low will source current (IIL) because of the internal pull ups.

In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count

input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in

the following table.

Port 1 also receives the low-order address bytes during Flash programming and

verification.





Table 4.2.1 Port1 specifications

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pull ups. The Port 2 output


high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are

externally being pulled low will source current (IIL) because of the internal pull-ups.

Port 2 emits the high-order address byte during fetches from external program

memory and during accesses to external data memory that uses 16-bit addresses (MOVX @

DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During

accesses to external data memory that uses 8-bit addresses (MOVX @ RI), Port 2 emits the

contents of the P2 Special Function Register.

Port 2 also receives the high-order address bits and some control signals during Flash

programming and verification.

Port 3

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output


high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are

externally being pulled low will source current (IIL) because of the pull-ups.

Port 3 also serves the functions of various special features of the AT89S52, as shown

in the following table.

Port 3 also receives some control signals for Flash programming and verification.





Table 4.2.2 Port3 specifications

RST

Reset input. A high on this pin for two machine cycles while the oscillator is running

resets the device. This pin drives High for 96 oscillator periods after the Watchdog times out.

The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the

default state of bit DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG

Address Latch Enable (ALE) is an output pulse for latching the low byte of the

address during accesses to external memory. This pin is also the program pulse input (PROG)

during flash programming.

In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency

and may be used for external timing or clocking purposes. Note, however, that one ALE

pulse is skipped during each access to external data memory.

If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With

the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is

weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in

external execution mode.

PSEN

Program Store Enable (PSEN) is the read strobe to external program memory. When the

AT89S52 is executing code from external program memory, PSEN is activated twice each

machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA/VPP

External access enables. EA must be strapped to GND in order to enable the device to

fetch code from external program memory locations starting at 0000H up to FFFFH.

Note, however, that if lock bit 1 is programmed, EA will be internally latched on

reset. EA should be strapped to VCC for internal program executions. This pin also receives

the 12-volt programming enable voltage (VPP) during Flash programming.





XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating

circuit.

XTAL2

Output from the inverting oscillator amplifier.

Special Function Registers

A map of the on-chip memory area called the Special Function Register (SFR) space

is shown in Table 1. Note that not all of the addresses are occupied, and unoccupied

addresses may not be implemented on the chip. Read accesses to these addresses will in

general return random data, and write accesses will have an indeterminate effect.

User software should not write 1s to these unlisted locations, since they may be used

in future products to invoke new features. In that case, the reset or inactive values of the new

bits will always be 0.

Timer 2 Registers

Control and status bits are contained in registers T2CON (shown in Table 2) and T2MOD

(shown in Table 3) for Timer 2. The register pair (RCAP2H, RCAP2L) is the Capture/Reload

registers for Timer 2 in 16-bit capture mode or 16-bit auto-reload mode.

Interrupt Registers

The individual interrupt enable bits are in the IE register. Two priorities can be set for

each of the six interrupt sources in the IP register.

Dual Data Pointer Registers

To facilitate accessing both internal and external data memory, two banks of 16-bit Data

Pointer Registers are provided: DP0 at SFR address locations 82H-83H and DP1 at 84H-85H.

Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1. The user should always





initialize the DPS bit to the appropriate value before accessing the respective Data Pointer

Register.

Power Off Flag

The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF is set to “1”

during power up. It can be set and rest under software control and is not affected by reset.

Memory Organization

MCS-51 devices have a separate address space for Program and Data Memory. Up to

64K bytes each of external Program and Data Memory can be addressed.

Program Memory

If the EA pin is connected to GND, all program fetches are directed to external

memory. On the AT89S52, if EA is connected to VCC, program fetches to addresses 0000H

through 1FFFH are directed to internal memory and fetches to addresses 2000H through

FFFFH are to external memory.

Data Memory

The AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a

parallel address space to the Special Function Registers. This means that the upper 128 bytes

have the same addresses as the SFR space but are physically separate from SFR space.

When an instruction accesses an internal location above address 7FH, the address

mode used in the instruction specifies whether the CPU accesses the upper 128 bytes of RAM

or the SFR space. Instructions which use direct addressing access of the SFR space.

For example, the following direct addressing instruction accesses the SFR at location

0A0H (which is P2).

MOV 0A0H, #data

Instructions that use indirect addressing access the upper 128 bytes of RAM. For

example, the following indirect addressing instruction, where R0 contains 0A0H, accesses the

data byte at address 0A0H, rather than P2 (whose address is 0A0H).

MOV @R0, #data





Note that stack operations are examples of indirect addressing, so the upper 128 bytes

of data RAM are available as stack space.

Watchdog Timer(One-time Enabled with Reset-out)

The WDT is intended as a recovery method in situations where the CPU may be

subjected to software upsets. The WDT consists of a 13-bit counter and the Watchdog Timer

Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To enable the

WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location

0A6H). When the WDT is enabled, it will increment every machine cycle while the oscillator

is running. The WDT timeout period is dependent on the external clock frequency. There is

no way to disable the WDT except through reset (either hardware reset or WDT overflow

(reset). When WDT overflows, it will drive an output RESET HIGH pulse at the RST pin.

Using the WDT

To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST

register (SFR location 0A6H). When the WDT is enabled, the user needs to service it by

writing 01EH and 0E1H to WDTRST to avoid a WDT overflow. The 13-bit counter

overflows when it reaches 8191 (1FFFH), and this will reset the device. When the WDT is

enabled, it will increment every machine cycle while the oscillator is running. This means the

user must reset the WDT at least every 8191 machine cycles. To reset the WDT the user must

write 01EH and 0E1H to WDTRST. DTRST is a write-only register. The WDT counter

cannot be read or written. When WDT overflows, it will generate an output RESET pulse at

the RST pin. The RESET pulse duration is 96xTOSC, where TOSC=1/FOSC. To make the

best use of the WDT, it should be serviced in those sections of code that will periodically be

executed within the time required to prevent a WDT reset.

WDT during Power-down and Idle

In Power-down mode the oscillator stops, which means the WDT also stops. While in

Power-down mode, the user does not need to service the WDT. There are two methods of

exiting Power-down mode: by a hardware reset or via a level-activated external interrupt

which is enabled prior to entering Power-down mode. When Power-down is exited with

hardware reset, servicing the WDT should occur as it normally does whenever the AT89S52

is reset. Exiting Power-down with an interrupt is significantly different. The interrupt is held





low long enough for the oscillator to stabilize. When the interrupt is brought high, the

interrupt is serviced. To prevent the WDT from resetting the device while the interrupt pin is

held low, the WDT is not started until the interrupt is pulled high. It is suggested that the

WDT be reset during the interrupt service for the interrupt used to exit Power-down mode.

To ensure that the WDT does not overflow within a few states of exiting Power-

down, it is best to reset the WDT just before entering Power-down mode.

Before going into the IDLE mode, the WDIDLE bit in SFR AUXR is used to

determine whether the WDT continues to count if enabled. The WDT keeps counting during

IDLE WDIDLE bit = 0) as the default state. To prevent the WDT from resetting the

AT89S52 while in IDLE mode, the user should always set up a timer that will periodically

exit IDLE, service the WDT, and reenter IDLE mode. With WDIDLE bit enabled, the WDT

will stop to count in IDLE mode and resumes the count upon exit from IDLE.

UART

Serial data communication uses two methods, asynchronous and synchronous. The

synchronous method transfers a block of data (characters ) at a time, while the asynchronous

method transfers a single byte at a time. It is possible to write software to use either of these

methods, but programs can be tedious and long. For this reason, there are special IC chips

made by the manufacturers for the serial data communications. These chips are commonly

referred to as UART ( universal asynchronous receiver-transmitter) and USART ( universal

synchronous receiver-transmitter). The 8052 has built-in UART.

Timer 0

The 16-bit register of timer 0 is accessed as low byte and high byte. The low byte register is

called TL0 ( Timer 0 low byte) and the high byte register is referred to as TH0 ( Timer 0 high

byte). These registers can be accessed like any other registers , such as A,B,R0,R1,R2 etc. for

example the instruction “MOV TL0,#4FH” moves the value 4FH into TL0, the low byte of

Timer 0. These registers can also be read like any other register. For example, “MOV

R5,TH0” saves TH0 ( high byte of Timer 0) in R5.





Timer1

Timer 1 is also 16 bits and its 16-bit register is split into two bytes, referred to as TL1

(Timer 1 low byte ) and TH1 ( Timer 1 high byte). These registers are accessible in the same

way as the registers of Timer 0.

Timer 2

Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event

counter. The type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 2).

Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate

generator. The modes are selected by bits in T2CON, as shown in Table 3. Timer 2 consists

of two 8-bit registers, TH2 and TL2. In the Timer function, the TL2 register is incremented

every machine cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is

1/12 of the oscillator frequency.

Table 4.2.3Timer2 Operating Modes of AT89S52

In the Counter function, the register is incremented in response to a 1-to-0 transition at its

corresponding external input pin, T2. In this function, the external input is sampled during

S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the

next cycle, the count is incremented. The new count value appears in the register during S3P1

of the cycle following the one in which the transition was detected. Since two machine

cycles (24 oscillator periods) are required to recognize a 1-to-0 transition, the maximum

count rate is 1/24 of the oscillator frequency. To ensure that a given level is sampled at least

once before it changes, the level should be held for at least one full machine cycle.





Oscillator Characteristics

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can

be configured for use as an on-chip oscillator, as shown in Figure 11. Either a quartz

crystal or ceramic resonator may be used. To drive the device from an external clock source,

XTAL2 should be left unconnected while XTAL1 is driven, as shown in Figure 12. There are

no requirements on the duty cycle of the external clock signal, since the input to the internal

clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage

high and low time specifications must be observed.

Oscillator connections

Figure 4.2.3 Oscillator Connections of AT89S52

Note: C1, C2 = 30 pF ± 10 pF for Crystals

= 40 pF ± 10 pF for Ceramic Resonators





External Clock Drive Configuration

Figure 4.2.4External Clock Drive Configuration of AT89S52

Idle Mode

In idle mode, the CPU puts itself to sleep while all the on chip peripherals remain active. The

mode is invoked by software. The content of the on-chip RAM and all the specialfunctions

registers remain unchanged during this mode. The idle mode can be terminated by any

enabled interrupt or by a hardware reset. Note that when idle mode is terminated by a

hardware reset, the device normally resumes program execution from where it left off, up to

two machine cycles before the internal reset algorithm takes control. On-chip hardware

inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To

eliminate the possibility of an unexpected write to a port pin when idle mode is terminated by

a reset, the instruction following the one that invokes idle mode should not write to a port pin

or to external memory.

Power-down Mode

In the Power-down mode, the oscillator is stopped, and the instruction that invokes Power-

down is the last instruction executed. The on-chip RAM and Special Function Registersretain

their values until the Power-down mode is terminated. Exit from Power-down mode can be

initiated either by a hardware reset or by an enabled external interrupt. Reset redefines the

SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is





restored to its normal operating level and must be held active long enough to allow the

oscillator to restart and stabilize.

Status of External Pins during Idle and Power-down Modes

Table 4.2.4 Power down and Idle Modes of AT89S52





5. FUNCTIONAL DESCRIPTIONS

5.1 Lcd Display

Liquid crystal display (LCD) has material which combines the properties of both

liquid and crystals. They have a temperature range within which the molecules are almost as

mobile as they would be in a liquid, but are grouped together in an order form similar to a

crystal.

Fig 5.1.1 LCDmodule

More microcontroller devices are using 'smart LCD' displays to output visual

information. The following discussion covers the connection of a Hitachi LCD display to a

PIC microcontroller. LCD displays designed around Hitachi's LCD HD44780 module, are

inexpensive, easy to use, and it is even possible to produce a readout using the 8 x 80 pixels

of the display. Hitachi LCD displays have a standard ASCII set of characters plus Japanese,

Greek and mathematical symbols.





Hardware Diagram

Fig 5.1.2 LCD pin configuration

For an 8-bit data bus, the display requires a +5V supply plus 11 I/O lines. For a 4-bit

data bus it only requires the supply lines plus seven extra lines. When the LCD display is not

enabled, data lines are tri-state which means they are in a state of high impedance (as though

they are disconnected) and this means they do not interfere with the operation of the

microcontroller when the display is not being addressed. The LCD also requires 3 "control"

lines from the microcontroller.

When the LCD is initialized, it is ready to continue receiving data or instructions. If it

receives a character, it will write it on the display and move the cursor one space to the right.

The Cursor marks the next location where a character will be written. When we want to write

a string of characters, first we need to set up the starting address, and then send one character

at a time.





Pins description

Table 5.1 pins for LCD

Logic status on control lines

RS (Command / Data):This bit is to specify weather received byte is command or data. So that LCD can recognize the operation to be performed based on the bit status.

RS = 0 => CommandRS = 1 => Data

RW (Read / Write)

RW bit is to specify weather controller wants READ from LCD or WRITE to LCD. The READ operation here is just ACK bit to know weather LCD is free or not.

RW = 0 => WriteRW = 1 => Read

EN (Enable LCD)

EN bit is to ENABLE or DISABLE the LCD. When ever controller wants to write some thing into LCD or READ acknowledgment from LCD it needs to enable the LCD.

EN = 0 => High ImpedanceEN = 1 => Low Impedance





ACK (LCD Ready)

ACK bit is to acknowledge the MCU that LCD is free so that it can send new command or data to be stored in its internal Ram locations.

ACK = 1 => Not ACKACK = 0 => ACK

Reading data from the LCD is done in the same way, but control line R/W has to be high.

When we send a high to the LCD, it will reset and wait for instructions. Typical instructions

sent to LCD display after a reset are: turning on a display, turning on a cursor and writing

characters from left to right. Characters that can be shown on the display are stored in data

display (DD) RAM. The size of DDRAM is 80 bytes.

Before we access DD RAM after defining a special character, the program must set

the DD RAM address. Writing and reading data from any LCD memory is done from the last

address which was set up using set-address instruction. Once the address of DD RAM is set, a

new written character will be displayed at the appropriate place on the screen. Until now we

discussed the operation of writing and reading to an LCD as if it were an ordinary memory.

But this is not so. The LCD controller needs 40 to 120 microseconds (uS) for writing and

reading. Other operations can take up to 5 mS. During that time, the microcontroller can not

access the LCD, so a program needs to know when the LCD is busy. We can solve this in two

ways.One way is to check the BUSY bit found on data line D7. This is not the best method

because LCD's can get stuck, and program will then stay forever in a loop checking the

BUSY bit. The other way is to introduce a delay in the program. The delay has to be long

enough for the LCD to finish the operation in process.

At the beginning we mentioned that we needed 11 I/O lines to communicate with an LCD.

However, we can communicate with an LCD through a 4-bit data bus. Thus we can reduce

the total number of communication lines to seven.





5.2 Power Supply Unit

The input to the circuit is applied from the regulated power supply. The a.c. input i.e.,

230V from the mains supply is step down by the transformer to 12V and is fed to a rectifier.

The output obtained from the rectifier is a pulsating d.c voltage. So in order to get a pure d.c

voltage, the output voltage from the rectifier is fed to a filter to remove any a.c components

present even after rectification. Now, this voltage is given to a voltage regulator to obtain a

pure constant dc voltage.

Fig 5.2.1 power supply

Power supply unit consists of following units

i) Step down transformer

ii) Rectifier unit

iii) Input filter

iv).Regulator unit

v) Output filter





Stepdown Transformer

The Step down Transformer is used to step down the main supply voltage from 230V AC to

lower value. This 230 AC voltage cannot be used directly, thus it is stepped down. The

Transformer consists of primary and secondary coils. To reduce or step down the voltage, the

transformer is designed to contain less number of turns in its secondary core. The output from

the secondary coil is also AC waveform. Thus the conversion from AC to DC is essential.

This conversion is achieved by using the Rectifier Circuit/Unit.

Step down transformers can step down incoming voltage, which enables you to have the

correct voltage input for your electrical needs. For example, if our equipment has been

specified for input voltage of 12 volts, and the main power supply is 230 volts, we will need a

step down transformer, which decreases the incoming electrical voltage to be compatible with

your 12 volt equipment.

Rectifier Unit

The Rectifier circuit is used to convert the AC voltage into its corresponding DC voltage. The

most important and simple device used in Rectifier circuit is the diode. The simple function

of the diode is to conduct when forward biased and not to conduct in reverse bias. Now we

are using three types of rectifiers. They are

1. Half-wave rectifier

2. Full-wave rectifier

3. Bridge rectifier

Half-Wave Rectifier

In half wave rectification, either the positive or negative half of the AC wave is passed, while

the other half is blocked. Because only one half of the input waveform reaches the output, it

is very inefficient if used for power transfer. Half-wave rectification can be achieved with a

single diode in a one phase supply, or with three diodes in a three-phase supply

Bridge Rectifier





A bridge rectifier makes use of four diodes in a bridge arrangement to achieve full-

wave rectification. This is a widely used configuration, both with individual diodes wired as

shown and with single component bridges where the diode bridge is wired internally.

A diode bridge or bridge rectifier is an arrangement of four diodes in a bridge

configuration that provides the same polarity of output voltage for either polarity of input

voltage. When used in its most common application, for conversion of alternating current

(AC) input into direct current (DC) output, it is known as a bridge rectifier. A bridge rectifier

provides full-wave rectification from a two-wire AC input, resulting in lower cost and weight

as compared to a center-tappedtransformer design.

The Forward Bias is achieved by connecting the diode’s positive with positive of the

battery and negative with battery’s negative. The efficient circuit used is the Full wave

Bridge rectifier circuit. The output voltage of the rectifier is in rippled form, the ripples from

the obtained DC voltage are removed using other circuits available. The circuit used for

removing the ripples is called Filter circuit.

Input Filter

Capacitors are used as filter. The ripples from the DC voltage are removed and pure

DC voltage is obtained. And also these capacitors are used to reduce the harmonics of the

input voltage. The primary action performed by capacitor is charging and discharging. It

charges in positive half cycle of the AC voltage and it will discharge in negative half cycle.

So it allows only AC voltage and does not allow the DC voltage. This filter is fixed before

the regulator. Thus the output is free from ripples.

Regulator Unit

Regulator regulates the output voltage to be always constant. The output voltage is

maintained irrespective of the fluctuations in the input AC voltage. As and then the AC

voltage changes, the DC voltage also changes. Thus to avoid this Regulators are used. Also

when the internal resistance of the power supply is greater than 30 ohms, the output gets

affected. Thus this can be successfully reduced here. The regulators are mainly classified for

low voltage and for high voltage. Further they can also be classified as

i) Positive regulator




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

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

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

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

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

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

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

http://en.wikipedia.org/wiki/Polarity_(physics)

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

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


1. input pin

2. ground pin

3. output pin

It regulates the positive voltage.

ii) Negative regulator

1. ground pin

2. input pin

3. output pin

It regulates the negative voltage.

Fixed Regulators

Fig 5.2.2 An assortment of 78xx series ICs

"Fixed" three-terminal linear regulators are commonly available to generate fixed voltages of

plus 3 V, and plus or minus 5 V, 9 V, 12 V, or 15 V when the load is less than about 7

amperes.

7805 Voltage Regulator

The 7805 provides circuit designers with an easy way to regulate DC voltages to 5v.

Encapsulated in a single chip/package (IC), the 7805 is a positive voltage DC regulator that

has only 3 terminals. They are: Input voltage, Ground, Output Voltage.

General Features:




http://en.wikipedia.org/wiki/File:7800_IC_regulators.jpg


Output Current up to 1A

Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V

Thermal Overload Protection

Short Circuit Protection

Output Transistor Safe Operating Area Protection

Output Filter

The Filter circuit is often fixed after the Regulator circuit. Capacitor is most often used as

filter. The principle of the capacitor is to charge and discharge. It charges during the positive

half cycle of the AC voltage and discharges during the negative half cycle. So it allows only

AC voltage and does not allow the DC voltage. This filter is fixed after the Regulator circuit

to filter any of the possibly found ripples in the output received finally. Here we used 0.1µF

capacitor. The output at this stage is 5V and is given to the Microcontroller. The output

voltage overshoots when the load is removed or a short clears. When the load is removing

from a switching mode power supply with a LC low-pass output filter, the only thing the

control loop can do is stop the switching action so no more energy is taken from the source.

The energy that is stored in the output filter inductor is dumped into the output capacitor

causing a voltage overshoot.

The magnitude of the overshoot is the vector sum of two orthogonal voltages, the

output voltage before the load is removed and the current through the inductor times the

characteristic impedance of the output filter, Zo = (L/C)^1/2. This can be derived from

conservation of energy considerations.

The two energies are equal when the load is removed, since the load is no longer

taking energy from the system. Equating the two energies, substituting zero current for the

final inductor current, then the solution for the final voltage Vf is:

This is the orthogonal vector sum of the output voltage and the load current times the

characteristic impedance and is illustrated in Figure .The problem becomes worse if the

current in the inductor is established by a short circuit on the output and the short circuit

clears. In this case, the initial voltage is zero (short circuit) and the overshoot is I*Zo, where I

can be very large, resulting in a ruinous overshoot.





5.3Serial Communication

Theinformation from micro controller is sent to system through serial communication

by using MAX-232 ic in between micro controller and RS232 DB9 connector. This MAX-

232 acts as voltage level translator i.e., the TTL logic voltage level is to be transformed to

RS232 DB9 connector voltage level of the system. In short a MAX –232 is nothing but a

clamper circuit, which consists of diodes and capacitors i.e., the voltage level translator. is

done through clamping circuit here diodes are inbuilt, whereas the capacitors are to be

connected externally .

Introduction

In this chapter we are going to cover basic concepts involved in the project such as serial

communication and modem activation commands. The serial communication is between the

modem and MCU and also between modem and PC.

Serial Communication

In order to connect micro controller to a modem or a pc to modem a serial port is

used. Serial is a very common protocol for device communication that is standard on almost

every PC. Most computers include two RS-232 based serial ports. Serial is also a common

communication protocol that is used by many devices for instrumentation; numerous GPIB-

compatible devices also come with an RS-232 port. Furthermore, serial communication can

be used for data acquisition in conjunction with a remote sampling device

The concept of serial communication is simple. The serial port sends and receives

bytes of information one bit at a time. Although this is slower than parallel communication,

which allows the transmission of an entire byte at once, it is simpler and can be used over

longer distances. For example, the IEEE 488 specifications for parallel communication state

that the cabling between equipment can be no more than 20 meters total, with no more than 2

meters between any two devices. serial, however, can extend as much as 1200 meters.

Typically, serial is used to transmit ASCII data. Communication is completed using 3

transmission lines: (1) Ground, (2) Transmit, and (3) Receive. Since serial is asynchronous,

the port is able to transmit data on one line while receiving data on another. Other lines are

available for handshaking, but are not required. The important serial characteristics are baud

rate, data bits, stop bits, and parity. For two ports to communicate, these parameters must

match.





Baud rate

It is a speed measurement for communication. It indicates the number of bit transfers

per second. For example, 300 baud is 300 bits per second. When a clock cycle is referred it

means the baud rate. For example, if the protocol calls for a 4800 baud rate, then the clock is

running at 4800Hz. This means that the serial port is sampling the data line at 4800Hz.

Common baud rates for telephone lines are 14400, 28800, and 33600. Baud rates greater than

these are possible, but these rates reduce the distance by which devices can be separated.

These high baud rates are used for device communication where the devices are located

together, as is typically the case with GPIB devices.

Data bits

A measurement of the actual data bits in a transmission. When the computer sends a

packet of information, the amount of actual data may not be a full 8 bits. Standard values for

the data packets are 5, 7, and 8 bits. Which setting choosen depends on what information

transferred? For example, standard ASCII has values from 0 to 127 (7 bits). Extended ASCII

uses 0 to 255 (8 bits). If the data being transferred is simple text (standard ASCII), then

sending 7 bits of data per packet is sufficient for communication. A packet refers to a single

byte transfer, including start/stop bits, data bits, and parity. Since the number of actual bits

depends on the protocol selected, the term packet is used to cover all instances.

Stop bits

Used to signal the end of communication for a single packet. Typical values are 1, 1.5, and 2

bits. Since the data is clocked across the lines and each device has its own clock, it is possible

for the two devices to become slightly out of sync. Therefore, the stop bits not only indicate

the end of transmission but also give the computers some room for error in the clock speeds.

The more bits that are used for stop bits, the greater the lenience in synchronizing the

different clocks, but the slower the data transmission rate.

Parity

A simple form of error checking that is used in serial communication. There are four

types of parity: even, odd, marked, and spaced. The option of using no parity is also





available. For even and odd parity, the serial port sets the parity bit (the last bit after the data

bits) to a value to ensure that the transmission has an even or odd number of logic high bits.

For example, if the data is 011, then for even parity, the parity bit is 0 to keep the number of

logic-high bits even. If the parity is odd, then the parity bit is 1, resulting in 3 logic-high bits.

Marked and spaced parity does not actually check the data bits, but simply sets the parity bit

high for marked parity or low for spaced parity. This allows the receiving device to know the

state of a bit to enable the device to determine if noise is corrupting the data or if the

transmitting and receiving device clocks are out of sync.

RS –232

RS-232 (ANSI/EIA-232 Standard) is the serial connection found on IBM-compatible

PCs. It is used for many purposes, such as connecting a mouse, printer, or modem, as well as

industrial instrumentation. Because of improvements in line drivers and cables, applications

often increase the performance of RS-232 beyond the distance and speed listed in the

standard. RS-232 is limited to point-to-point connections between PC serial ports and

devices. RS-232 hardware can be used for serial communication up to distances of 50 feet .

DB-9 pin connector

1 2 3 4 5

6 7 8 9

Pin Functions:

Data: TxD on pin 3, RxD on pin 2

Handshake: RTS on pin 7, CTS on pin 8, DSR on pin 6,

CD on pin 1, DTR on pin 4

Common: Common pin 5(ground)

Other: RI on pin 9

The method used by RS-232 for communication allows for a simple connection of

three lines: Tx, Rx, and Ground. The three essential signals for 2 way RS-232

Communications are these:

TXD: carries data from DTE to the DCE.

RXD: carries data from DCE to the DTE





SG: signal ground

Here in our project DTE is the micro controller at the remote station and PC at the

base station, DCE is the modem at both the stations. However the data to be transmitted, both

sides have to be clocking the data at the same baud rate. Even though this method is sufficient

for most applications, it is limited in being able to respond to problems such as the receiver

getting overloaded. This is where serial handshaking can help. This method uses actual

hardware lines. There are two pairs of hand shaking signals DTR/DSR and

RTS/CTS each pair has uses defined by the standard. There are several ways to

describe the state of RS-232 and other control signals. A signal with a valid positive voltage

may be described as true to indicate that it is in the active state for example when DTR is true

the data terminal is ready. to bring the signal true the controlling device raises the line. A

signal with a valid negative voltage may be described as false or ff to indicate that it’s

inactive state .for example when DTR is false, the data terminal is not ready. To bring the

signal false the controlling device lowers the line. The DTR/DSR handshake is intended for

providing information about the status of the phone line or other communications channel

connected to the modem. the terminal raises DTR to request the modem to connect to the

communication channel. In response the modem raises DSR to indicate that it is

connected .DSR is false when the modem is not connected to the communication channel or

on detecting a fault. the terminal may also raise DTR in response to RI (ring indicator) to tell

the modem to answer a call.

The RTS/CTS handshake provides additional information about whether a device is

ready to receive data. This signal pair provides a full handshake. when the terminal has data

to send ,it raises RTS (request to send). In response the modem raises CTS (clear to send) to

indicate that it is ready to receive. When the transmission is finished the terminal may lower

RTS. the modem should then be continue processing whatever data it has received and lower

CTS when it’s ready to respond to the next RTS. When RTS is false, the terminal should wait

for CTS to be false before raising RTS to request a new transmission.

RI is true when a ringing signal is present on the communications channel. The signal

is true when the audible ring is present and false in the pauses between the rings .The final

control signal is the CD (carrier detect). The modem raises CD when it detects a signal of

expected frequency on the phone lines, indicating that a connection has been established to a

remote modem.





MAX232

PIN DIAGRAM OF MAX232

Fig 5.3 max232 pin diagram

This module is primary of interest for people building their own electronics with an

RS-232 interface. Off-the-shelf computers with RS-232 interfaces already contain the

necessary electronics, and there is no need to add the circuitry as described here.

Serial RS-232 (V.24) communication works with voltages (-15V ... -3V for high [sic])

and +3V ... +15V for low [sic]) which are not compatible with normal computer logic

voltages. On the other hand, classic TTL computer logic operates between 0V ... +5V

(roughly 0V ... +0.8V for low, +2V ... +5V for high). Modern low-power logic operates in the

range of 0V ... +3.3V or even lower.

So, the maximum RS-232 signal levels are far too high for computer logic electronics,

and the negative RS-232 voltage for high can't be grokked at all by computer logic.

Therefore, to receive serial data from an RS-232 interface the voltage has to be reduced, and

the low and high voltage level inverted. In the other direction (sending data from some logic

over RS-232) the low logic voltage has to be "bumped up", and a negative voltage has to be

generated, too.





Table 5.3.1Voltage levels for RS232 and TTL

All this can be done with conventional analog electronics, e.g. a particular power

supply and a couple of transistors or the once popular 1488 (transmitter) and 1489 (receiver)

ICs. However, since more than a decade it has become standard in amateur electronics to do

the necessary signal level conversion with an integrated circuit (IC) from the MAX232

family (typically a MAX232A or some clone). In fact, it is hard to find some RS-232

circuitry in amateur electronics without a MAX232A or some clone.

The MAX232 from Maxim was the first IC which in one package contains the

necessary drivers (two) and receivers (also two), to adapt the RS-232 signal voltage levels to

TTL logic. It became popular, because it just needs one voltage (+5V) and generates the

necessary RS-232 voltage levels (approx. -10V and +10V) internally. This greatly simplified

the design of circuitry. Circuitry designers no longer need to design and build a power supply

with three voltages (e.g. -12V, +5V, and +12V), but could just provide one +5V power

supply, e.g. with the help of a simple 78x05 voltage converter.

The MAX232 has a successor, the MAX232A. The ICs are almost identical, however,

the MAX232A is much more often used (and easier to get) than the original MAX232, and

the MAX232A only needs external capacitors 1/10th the capacity of what the original

MAX232 needs.

It should be noted that the MAX232(A) is just a driver/receiver. It does not generate

the necessary RS-232 sequence of marks and spaces with the right timing, it does not decode

the RS-232 signal, it does not provide a serial/parallel conversion. All it does is to convert

signal voltage levels. Generating serial data with the right timing and decoding serial data has

to be done by additional circuitry, e.g. by a 16550 UART or one of these small micro

controllers (e.g. Atmel AVR, Microchip PIC) getting more and more popular.





The MAX232 and MAX232A were once rather expensive ICs, but today they are

cheap. It has also helped that many companies now produce clones (i.e. Sipex). These clones

sometimes need different external circuitry, e.g. the capacities of the external capacitors vary.

It is recommended to check the data sheet of the particular manufacturer of an IC instead of

relying on Maxim's original data sheet.

The original manufacturer (and now some clone manufacturers, too) offers a large

series of similar ICs, with different numbers of receivers and drivers, voltages, built-in or

external capacitors, etc. E.g. The MAX232 and MAX232A need external capacitors for the

internal voltage pump, while the MAX233 has these capacitors built-in. The MAX233 is also

between three and ten times more expensive in electronic shops than the MAX232A because

of its internal capacitors. It is also more difficult to get the MAX233 than the garden variety

MAX232A.A similar IC, the MAX3232 is nowadays available for low-power 3V logic.

MAX232Application

The MAX232(A) has two receivers (converts from RS-232 to TTL voltage levels)

and two drivers (converts from TTL logic to RS-232 voltage levels). This means only two of

the RS-232 signals can be converted in each direction. The old MC1488/1498 combo

provided four drivers and receivers.

Typically a pair of a driver/receiver of the MAX232 is used for TX and RX and the

second one for CTS and RTS. There are not enough drivers/receivers in the MAX232 to also

connect the DTR, DSR, and DCD signals. Usually these signals can be omitted when e.g.

communicating with a PC's serial interface. If the DTE really requires these signals either a

second MAX232 is needed, or some other IC from the MAX232 family can be used (if it can

be found in consumer electronic shops at all). An alternative for DTR/DSR is also given

below.Maxim's data sheet explains the MAX232 family in great detail, including the pin

configuration and how to connect such an IC to external circuitry. Exactly to connect the RS-

232 signals to the IC. So here is one possible example:

MAX232 Pin Nbr. MAX232 Pin Name Signal Voltage DB9 Pin





7 T2out CTS RS-232 7

8 R2in RTS RS-232 8

9 R2out RTS TTL n/a

10 T2in CTS TTL n/a

11 T1in TX TTL n/a

12 R1out RX TTL n/a

13 R1in RX RS-232 2

14 T1out TX RS-232 3

15 GND GND 0 5

Table 5.3.2 RS232-DB9 pin Diagram

5.4 DC Motor

Introduction

Whenever a robotics hobbyist talk about making a robot, the first thing comes to his

mind ismaking the robot move on the ground. And there are always two options in front of

thedesigner whether to use a DC motor or a stepper motor. When it comes to speed, weight,

size,cost... DC motors are always preferred over stepper motors. There are many things which

youcan do with your DC motor when interfaced with a microcontroller. For example you

cancontrol the speed of motor; you can control the direction of rotation.In this part of tutorial

we will learn to interface and control of a DC motor with amicrocontroller. Usually H‐bridge

is preferred way of interfacing a DC motor. These days manyIC manufacturers have H‐bridge

motor driver available in the market like L293D is most used HBridgedriver IC. H‐bridge can

also be made with the help of transistors and MOSFETs etc.rather of being cheap, they only





increase the size of the design board, which is sometimes notrequired so using a small 16 pin

IC is preferred for this purpose.

DC Motor Driver (L293D)

L293D is a dual H-Bridge motor driver, So with one IC we can interface two DC

motors which can be controlled in both clockwise and counter clockwise direction and if you

have motor with fix direction of motion the you can make use of all the four I/Os to connect

up to four DC motors. L293Dhas output current of 600mA and peak output current of 1.2A

per channel. Moreover for protection of circuit from back EMF output diodes are included

within the IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has

made L293Da best choice for DC motor driver.

L293D Dual H-Bridge Motor Driver

5.4Pin diagram of L293D Motor Driver

L293D is a dual H-Bridge motor driver, so with one IC we can interface two

DCmotors which can be controlled in both clockwise and counter clockwise direction and if





you have motor with fix directionOf motion. You can make use of all the four I/Os to

connect up to four DC motors. L293D has output current of 600mA and peak output current

of 1.2A per channel. Moreover for protection of circuit from back EMF output diodes are

included with in the IC. The output supply(VCC2) has a wide range from 4.5V to 36V,which

has made L293D a best choice forDC motor driver.

A simple schematic for interfacing a DC motor using L293D is shown below.

FigureDC Motor Driver





6. SOFT WARE REQUIREMENTS

Keil an ARM Company makes C compilers, macro assemblers, real-time kernels,

debuggers, simulators, integrated environments, evaluation boards, and emulators for

ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.

The Keil 8051 Development Tools are designed to solve the complex problems facing

embedded software developers

Keil development tools for the 8051 Microcontroller Architecture support every level

of software developer from the professional applications engineer to the student just learning

about embedded software development.

When starting a new project, simply select the microcontroller you use from the

Device Database and the µVision IDE sets all compiler, assembler, linker, and memory

options for you.

Numerous example programs are included to help you get started with the most

popular embedded 8051 devices.

The Keil µVision Debugger accurately simulates on-chip peripherals (I²C, CAN,

UART, SPI, Interrupts, I/OPorts, A/D Converter, D/A Converter, and PWM Modules) of

your 8051 device. Simulation helps you understand hardware configurations and avoids time

wasted on setup problems. Additionally, with simulation, you can write and test applications

before target hardware is available

EMBEDDED ‘C’:

Ex: Hitec – c, Keil – c

HI-TECH Software makes industrial-strength software development tools and C

compilers that help software developers write compact, efficient embedded processor code.

For over two decades HI-TECH Software has delivered the industry's most reliable

embedded software development tools and compilers for writing efficient and compact code

to run on the most popular embedded processors. Used by tens of thousands of customers

including General Motors, Whirlpool, Qualcomm, John Deere and many others, HI-TECH's





reliable development tools and C compilers, combined with world-class support have helped

serious embedded software programmers to create hundreds of breakthrough new

solutions.Whichever embedded processor family you are targeting with your software,

whether it is the ARM, PICC or 8051 series, HI-TECH tools and C compilers can help you

write better code and bring it to market faster. HI-TECH PICC is a high-performance C

compiler for the Microchip PIC micro 10/12/14/16/17 series of microcontrollers. HI-TECH

PICC is an industrial-strength ANSI C compiler - not a subset implementation like some

other PIC compilers. The PICC compiler implements full ISO/ANSI C, with the exception of

recursion. All data types are supported including 24 and 32 bit IEEE standard floating point.

HI-TECH PICC makes full use of specific features and using an intelligent optimizer, can

generate high-quality code easily rivaling hand-written assembler. Automatic handling of

page and bank selection frees the programmer from the trivial details of assembler code.

EMBEDDED “C” COMPILER

ANSI C - full featured and portable.

Reliable - mature, field-proven technology.

Multiple C optimization levels .

An optimizing assembler.

Full linker, with overlaying of local variables to minimize RAM usage.

Comprehensive C library with all source code provided.

Includes support for 24-bit and 32-bit IEEE floating point and 32-bit

long data types.

Mixed C and assembler programming.

Unlimited number of source files.

Listings showing generated assembler.

Compatible - integrates into the MPLAB IDE, MPLABICD .

Runs on multiple platforms: Windows, Linux, UNIX, Mac OS X,

Solaris.





EMBEDDED SYSTEM TOOLS

ASSEMBLER

An assembler is a computer program for translating assembly language — essentially,

a mnemonic representation of machine language — into object code. A cross assembler (see

cross compiler) produces code for one type of processor, but runs on another. The

computational step where an assembler is run is known as assembly time. Translating

assembly instruction mnemonics into opcodes, assemblers provide the ability to use symbolic

names for memory locations (saving tedious calculations and manually updating addresses

when a program is slightly modified), and macro facilities for performing textual substitution

typically used to encode common short sequences of instructions to run inline instead of in a

subroutine. Assemblers are far simpler to write than compilers for high-level languages.

ASSEMBLY LANGUAGE HAS SEVERAL BENEFITS

Speed: Assembly language programs are generally the fastest programs around.

Space: Assembly language programs are often the smallest.

Capability: You can do things in assembly which are difficult or impossible in High

level languages.

Knowledge: Your knowledge of assembly language will help you write better

programs, even when using High level languages. An example of an assembler we use in our

project is RAD 51.

SIMULATOR

Simulator is a machine that simulates an environment for the purpose of training or

research. We use a UMPS simulator for this purpose in our project.

UMPS

Universal microprocessor program simulator simulates a microcontroller with its

external environment. UMPS is able to simulate external components connected to the

microcontroller. Then, debug step is dramatically reduced. UMPS is not dedicated to only




http://en.wikipedia.org/wiki/High-level_language

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

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

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

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

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

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

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

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

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

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


one microcontroller family, it can simulate all kind of microcontrollers. The main limitation

is to have less than 64K-Bytes of RAM and ROM space and the good microcontroller library.

UMPS provide all the facilities other low-cost simulator does not have. It offers the user to

see the "real effect" of a program and a way to change the microcontroller family without

changing IDE. UMPS provide a low-cost solution to the problems. UMPS is really the best

solution to your evaluation.

UMPS KEY FEATURES

The speed, UMPS can run as fast as 1/5 the real microcontroller speed. No need to wait

2 days to see the result of a LCD routine access. All the microcontroller parts are simulated,

interrupts, communication protocol, parallel handshake, timer and so on. UMPS have an

integrated assembler/disassembler and debugger. It is able to accept an external assembler or

compiler. It has a text editor which is not limited to 64K-bytes and shows keyword with

color. It can also communicate with an external compiler to integrate all the debug facilities

you need.UMPS is universal, it can easily be extended to other microcontroller with a library.

Ask us for toolkit development.External resource simulation is not limited. It can be extended

to your proper needs by writing your own DLL.UMPS allows you to evaluate at the lowest

cost the possibility to build a microcontroller project without any cable. - UMPS include a

complete documentation on each microcontroller which describe special registers and each

instruction.

USER INTERFACES

User interfaces for embedded systems vary widely, and thus deserve some special comment.

User interface is the ultimate aim for an embedded module as to the user to check the output

with complete convenience. One standard interface, widely used in embedded systems, uses

two buttons (the absolute minimum) to control a menu system (just to be clear, one button

should be "next menu entry" the other button should be "select this menu entry").

Another basic trick is to minimize and simplify the type of output. Designs sometimes

use a status light for each interface plug, or failure condition, to tell what failed. A cheap

variation is to have two light bars with a printed matrix of errors that they select- the user can

glue on the labels for the language that he speaks. For example, most small computer printers

use lights labeled with stick-on labels that can be printed in any language. In some markets,





these are delivered with several sets of labels, so customers can pick the most comfortable

language.

In many organizations, one person approves the user interface. Often this is a

customer, the major distributor or someone directly responsible for selling the system.

PLATFORM

There are many different CPU architectures used in embedded designs such as ARM,

MIPS, Coldfire/68k, PowerPC, X86, PIC, 8051, Atmel AVR, H8, SH, V850, FR-V, M32R

etc.

This in contrast to the desktop computer market, which as of this writing (2003) is

limited to just a few competing architectures, mainly the Intel/AMDx86, and the

Apple/Motorola/IBMPowerPC, used in the Apple Macintosh. With the growing acceptance

of Java in this field, there is a tendency to even further eliminate the dependency on specific

CPU/hardware (and OS) requirements.

Standard PC/104 is a typical base for small, low-volume embedded and ruggedized

system design. These often use DOS, Linux or an embedded real-time operating system such

as QNX or Inferno.

A common configuration for very-high-volume embedded systems is the system on a

chip, an application-specific integrated circuit, for which the CPU was purchased as

intellectual property to add to the IC's design. A related common scheme is to use a field-

programmable gate array, and program it with all the logic, including the CPU. Most modern

FPGAs are designed for this purpose.

TOOLS

Like typical computer programmers, embedded system designers use compilers,

assemblers, and debuggers to develop embedded system software. However, they also use a

few tools that are unfamiliar to most programmers.

Software companies that specialize in the embedded market Ported from the GNU software

development tools.Sometimes, development tools for a personal computer can be used if the

embedded processor is a close relative to a common PC processor. Embedded system

designers also use a few software tools rarely used by typical computer programmers.




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

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

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

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

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

http://en.wikipedia.org/wiki/Field-programmable_gate_array

http://en.wikipedia.org/wiki/Field-programmable_gate_array

http://en.wikipedia.org/wiki/Application-specific_integrated_circuit

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

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

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

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

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

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

http://en.wikipedia.org/wiki/PC/104

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

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

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

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

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

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

http://en.wikipedia.org/wiki/X86

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

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

http://en.wikipedia.org/wiki/As_of_2003

http://en.wikipedia.org/wiki/M32R

http://en.wikipedia.org/wiki/FR-V

http://en.wikipedia.org/wiki/V850

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

http://en.wikipedia.org/wiki/H8

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

http://en.wikipedia.org/wiki/8051

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

http://en.wikipedia.org/wiki/X86

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

http://en.wikipedia.org/wiki/68k

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

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

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

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


One common tool is an "in-circuit emulator" (ICE) or, in more modern designs, an

embedded debugger. This debugging tool is the fundamental trick used to develop embedded

code. It replaces or plugs into the microprocessor, and provides facilities to quickly load and

debug experimental code in the system. A small pod usually provides the special electronics

to plug into the system. Often a personal computer with special software attaches to the pod

to provide the debugging interface.

Another common tool is a utility program (often home-grown) to add a checksum or

CRC to a program, so it can check its program data before executing it.

An embedded programmer that develops software for digital signal processing often

has a math workbench such as MathCad or Mathematical to simulate the mathematics.

Less common are utility programs to turn data files into code, so one can include any

kind of data in a program. A few projects use Synchronous programming languages for extra

reliability or digital signal processing.

DEBUGGING

Debugging is usually performed with an in-circuit emulator, or some type of debugger

that can interrupt the microcontroller's internal microcode. The microcode interrupt lets the

debugger operate in hardware in which only the CPU works. The CPU-based debugger can

be used to test and debug the electronics of the computer from the viewpoint of the CPU.

This feature was pioneered on the PDP-11.

As the complexity of embedded systems grows, higher level tools and operating

systems are migrating into machinery where it makes sense. For example, cell phones,

personal digital assistants and other consumer computers often need significant software that

is purchased or provided by a person other than the manufacturer of the electronics. In these

systems, an open programming environment such as Linux, OSGi or Embedded Java is

required so that the third-party software provider can sell to a large market.

OPERATING SYSTEM

Embedded systems often have no operating system, or a specialized embedded operating

system (often a real-time operating system), or the programmer is assigned to port one of

these to the new system.




http://en.wikipedia.org/wiki/Real-time_operating_system

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

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

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

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

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

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

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

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

http://en.wikipedia.org/wiki/PDP-11

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

http://en.wikipedia.org/wiki/In-circuit_emulator

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

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

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

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

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

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

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


BUILT- IN SELF- TEST

Most embedded systems have some degree or amount of built-in self-test.

There are several basic types.

1. Testing the computer.

2. Test of peripherals.

3. Tests of power.

4. Communication tests.

5. Cabling tests.

6. Rigging tests.

7. Consumables test.

8. Operational test.





7.CODE GENERATION

#include<reg52.h>

#include<lcd.h>

#include<serial.h>

#include<string.h>

sbit SW = P3^7;

sbit motor1 = P2^0;

unsigned char D[20];

unsigned char i,value;

bit flag;

void Disp_Hex(unsigned char);

void FINGER_FUN_IDT(); // finger identification

void serial(void ) interrupt 4

{

if (RI)

{

D[i] = SBUF;

if (i>15){flag=1;}

else i++;

}

}

void main()

{

bit scan_flag;





SConfig();

scan_flag=0;motor1=0;

LCD_Init();

LCD_Cmd(0x80);

Disp_Str(" WELCOME ");

Delay(50);clear();

LCD_Cmd(0x80);

Disp_Str(" finger print ");

LCD_Cmd(0xC0);

Disp_Str(" BASED PROJECT ");

Delay(100);

LCD_Cmd(0x80);

Disp_Str(" PRESS SWITCH ");

while(1) // infinite loop

{

LCD_Cmd(0x80);Disp_Str(" PRESS SWITCH ");

if (SW==0) //scanning switch

{

FINGER_FUN_IDT(); //command identify function

EA=1;ES=1;

Delay(300);

}

if (flag==1)

{





flag=0;

if (D[12] == 0x00 && D[13] == 0x00 && D[14] == 0x00)

{

scan_flag=1;

LCD_Cmd(0x80);

Disp_Str(" VALID ");

LCD_Cmd(0xC0);

Disp_Str(" PERSON1 ");

}

else if (D[12] == 0x00 && D[13] == 0x00 && D[14] == 0x01)

{

scan_flag=1;

LCD_Cmd(0x80);


LCD_Cmd(0xC0);


}

else if (D[12] == 0x00 && D[13] == 0x00 && D[14] == 0x02)

{

scan_flag=1;

LCD_Cmd(0x80);


LCD_Cmd(0xC0);


}

else if (D[12] == 0x02)





{

LCD_Cmd(0xC0);

Disp_Str("NO F.P ON SENSOR");

}

else if (D[12] == 0x09)

{

LCD_Cmd(0xC0);

Disp_Str("NO F.Pwere FOUND");

}

EA=ES=0;

}

if (scan_flag==1)

{

Delay(100);

LCD_Cmd(0x80);

Disp_Str(" DOOOR OPEN ");

motor1=0;

Delay(600);

LCD_Cmd(0x80);

Disp_Str(" DOOR CLOSED ");

motor1=1;

Delay(600);

motor1=0;

}

} //infinite loop end





} // main loop end

void FINGER_FUN_IDT()

{

Send_Char(0xEF);Send_Char(0x01);

Send_Char(0xFF);Send_Char(0xFF);Send_Char(0xFF);Send_Char(0xFF);

Send_Char(0x01);

Send_Char(0x00);Send_Char(0x03);

Send_Char(0x01);

Send_Char(0x00);Send_Char(0x05);

}





8.CONCLUSION

The project has been successfully implemented. In conclusion,”FINGER PRINT BASED

SECURITY SYSTEM” is used to provide security and authentication for an organization

using finger prints as forgery of that is not possible. The project report began with the

introduction to the basic functioning of Microcontrollerbased Identification, Authentication

and Setup of Security system.

Project deals withMicrocontroller as central controlling units for various other

sections like Biometrics FIM 3030 module, LCD etc. Interfacing between all sections

required for system and microcontroller 89S52 has been done successfully. For registration

interfacing between biometricsmodule and personal computer has also been done

successfully. When a new person whois not register with the system try to have access,

system refuses access and displaysmessage “Unidentified FP”. For the person who is

registered with the system can getaccess through doors according to their designation. Doors

opening and closing has beenachieved successfully.





9. FUTURE SCOPE

In this project we are using fingerprint module. Itis most widely used for security

purposes. This project is depend on the biometrics i.e fingerprint. It is very easy to implement

because Each person has his ownfingerprints with the permanent uniqueness. Compare to

normal security system it is better and in this we can further to implement in every office that

module contains total information of employes.

When a finger is kept at the finger print reader, it will give the information

accordingly to microcontroller by sending appropriate commands to the reader. If the

information matches with the one within the device then the DC motor interfaced to the

microcontroller responds accordingly. And if the information provided by the user is

incorrect or mismatch in finger prints is detected then access is denied. Finger print reader

and the microcontroller unit are connected using serial interface.

In future this system is used to provide security and authentication for an organization

using finger prints as forgery of that is not possible.





10. BIBLIOGRAPHY

NAME OF THE SITES

www.at89s52.com/pdf/

www.microchips.com

www.max232n.com/texas

www.mikroelektronika.co.yu/english/product/books/PICbook/0_Uvod.

www.wikipedia.com

www.atmel.databook.com

BOOKS

Customizing and programming microcontroller-MykePredcko-TMH publication-

2000

FIM30 user manual.

C programming for embedded systems- Kirk Zurell

“8051 and embedded system” by Mazid and Mazidi

Embedded Microcomputer system-onathanw.Valvano PHI publication2000

microcontroller inter facing- Douglasv.hallTMHpublication-2000




http://WWW.ATMEL.DATABOOK.COM/

http://WWW.MITEL.DATABOOK.COM/

http://www.mikroelektronika.co.yu/english/product/books/PICbook/0_Uvod

http://www.max232n.com/texas

http://www.micro/

http://www.at89s52.com/pdf/

finger print based security system

Documents