Md Ranju Sardar - DUET

DESIGN AND DEVELOPMENT OF MICROCONTROLLER BASED

SYSTEM FOR GENERATION, TRANSMISSION AND RECEPTION

OF DIGITAL ENERGY METER READING USING SMS

TECHNOLOGY

Md Ranju Sardar

DEPARTMENT OF ELECTRICAL & ELECTRONIC ENGINEERING

DHAKA UNIVERSITY OF ENGINEERING AND TECHNOLOGY,

GAZIPUR

January 2012

ii

DESIGN AND DEVELOPMENT OF MICROCONTROLLER BASED

SYSTEM FOR GENERATION, TRANSMISSION AND RECEPTION

OF DIGITAL ENERGY METER READING USING SMS

TECHNOLOGY

A thesis

submitted to the Department of Electrical and Electronic

Engineering DUET, Gazipur in partial completion of the

requirements for the degree of

MASTER OF SCIENCE IN ELECTRICAL AND ELECTRONIC

ENGINEERING

by

Md Ranju Sardar

Under supervision of

Dr. Md. Bashir Uddin

Professor & Head

DEPARTMENT OF ELECTRICAL & ELECTRONIC ENGINEERING DHAKA UNIVERSITY OF ENGINEERING AND TECHNOLOGY,

GAZIPUR

January 2012

v

ACKNOWLEDGEMENTS

I would like to express my appreciation and reflective thanks to my supervisor

Professor, Dr.Md Bashir Uddin, Head, Department of Electrical and Electronic

Engineering of Dhaka University of Engineering and Technology Gazipur for his

authentic direction, encouragement and cooperative support whole over my thesis

work. I am grateful to Assistant Professor Mohammad shazzat Hossain, Department

of Electrical and Electronic Engineering of Dhaka University of Engineering and

Technology Gazipur.I would also like to express my gratefulness and in particular

thanks to Md Abdul Mannan, Professor and Dean, Department of Electrical and

Electronic Engineering of Dhaka University of Engineering and Technology Gazipur

his cordial help and valuable suggestions. I would like to thank my parents and elder

brothers for their regular encouragements. I would like to get across my furthermost

gratitude towards Dr Md Anawarul Abedin, Associate professor, Department of

Electrical and Electronic Engineering of Dhaka University of Engineering and

Technology Gazipur for his Logitech support throughout this research work. I am

grateful to all of my colleagues and friends. I am also grateful to the librarian and all

the sets up of Dhaka University of Engineering and Technology for their back up.

January 2012 Md. Ranju Sardar

vi

ABSTRACT

The main objective of this thesis is to generate, transmit and receive the digital energy

meter reading into database server using SMS Technology. In fact the over all system

is divided into two units such as one is SMS message transmitting unit and another is

SMS message receiving unit. The SMS message transmitting unit consists of

microcontroller, energy measuring chip (EMC), GSM (Global System for mobile

communication) module, SIM (Subscriber Identification Module) and LCD display.

Consequently SMS message receiving unit consists of GSM modem, PC (Personal

Computer), SMS Enabler Software, SQL (Structured, Query Language) and database

server. In case of SMS message transmitting unit, microcontroller is interfaced with

energy measuring chip, GSM module and LCD display. In this system

microcontroller is used for controlling the interfacing equipment functions, data

reading, calculation, storage and display the meter reading on LCD display. The

microcontroller accumulates reading over a month and at the first moment of a month

the microcontroller sends the meter reading to GSM module. The GSM module

receives the corresponding reading from microcontroller, produces short message

based on the data reading and sends the message through mobile communication

systems. Lastly the meter reading is saved into database server via mobile

communication systems, GSM modem, SMS Enabler Software and SQL (Structured

Query Language). The system will play an important role to provide proper service to

the consumers by reducing cost, system loss and corruption and increasing reputation

of the organization. The introduction of the system helps maintain accuracy and make

friendly relationship between consumers and organization.

vii

CONTENTS

Pages Board of Examiners iii Declaration iv Acknowledgement v Abstract vi References xi Appendices xi Use of program xi List of Table xi List of Figures xiii Abbreviations xv

CHAPTER-1

INTRODUCTION

1.1 Back Ground of the Work 1 1.2 Present State of Art of Microcontroller Based System 3 1.2.1 System Architecture 3 1.2.1.1 Remote Meter 4 1.2.1.2 Central Server 6 1.3 Fundamental Terms Related to SMS Mode Meter Reading

System 8

1.3.1 Global System for Mobile Communication (GSM ) 9 1.3.2 GSM Frequencies 9 1.3.3 Short Message Service (SMS) 10 1.3.4 Microcontroller 10 1.3.5 PIC (Peripheral Interface Controller) 11 1.3.6 GSM Module and Modem 11 1.3.7 Subscriber Identity Module (SIM) 11 1.3.8 Digital Energy Meter 12 1.3.9 LCD (Liquid Crystal Display) 13 1.3.10 PICBASIC PRO Software 13 1.3.11 EPIC Win 14 1.3.12

SMS Enabler Software 14

1.3.13 SQL(Structured Query Language) 15 1.4 Objectives 15 1.5 Organization of the Thesis 15

viii

CHAPTER-2 GSM AND SMS TECHNOLOGY

2.1 Introduction 17 2.2 SMS as a Part of GSM 17 2.2.1 Initial Concept 17 2.2.2 Early Development 18 2.2.3 Early Implementation 19 2.2.4 Text Messing Outside GSM 20 2.2.5 SMS Today 20 2.2.6 Message Size 20 2.3 SMS Protocols 21 2.4 Network Reference Model for SMS 22 2.5 How Does SMS Work 23 2.6 Benefit of SMS 25 2.7 Application of SMS 25 2.8 Limitation of SMS 26 2.9 Initiatives and Future Developments of SMS 27 2.10 Description of GSM Network 28 2.11 Signaling in GSM 30 2.12 GSM Mobility 31 2.13 The GSM Specifications 32 2.13.1 Modulation 32 2.13.2 Access Methods 32 2.13.3 Transmission Rate 33 2.13.4 Frequency Band 33 2.13.5 Channel Spacing 33 2.13.6 Speech Coding 33 2.13.7 Speech Coding 33 2.14 Identifier in GSM Network 33 2.14.1 International Mobile Subscriber Identity 33 2.14.2 Mobile Station Integrated Service Digital Network Number 3 5 2.14.3 International Mobile Equipment Identifier 36 2.14.4 Mobile Station Roaming Number 37 2.15 GSM User Services 37 2.15.1 Tele services 38 2.15. 2 Voice Calls 38 2.15.3 Videotext and Facsimile 38 2.15.4 Bearer Services or Data Services 38 2.15.5 Bearer Services or Data Services 38 2.15.6 Supplementary Services 39

CHAPTER-3

MICROCONTROLLER ARCHITECTURE 3.1 Introduction 40 3.2 Components of Microcontroller 41 3.2.1 Microprocessor/CPU 42 3.2.2 Memory in a Microcontroller 42 3.2.2.1 Read only Memory (ROM) 42 3.2.2.2

Random Access Memory (RAM) 42

ix

3.2.3 Input/Output Ports 44 3.3 Embedded Design of microcontroller 45 3.3.1 Interrupts 46 3.3.2 Programs 46 3.3.3 Common Feature of Microcontrollers 46

3.3.4 Special Features of Microcontrollers 47 3.4 Programming Environments 48 3.5 Microcontroller Embedded Memory Technology 49 3.5.1 Data 50 3.5.2 Firmware 50 3.6 PIC Microcontrollers 50 3.6.1 Core Architecture of PIC Microcontroller 50 3.6.1.1 Data Space for RAM 51 3.6.1.2 Code Space 52 3.6.1.3 Word Size 52 3.6.1.4 Stacks 52 3.6.1.5 Instruction Set 52 3.6.1.6 Performance 53 3.7 Block Diagram of the study Base PIC18F2550 Microcontroller 54 3.8 Pin Diagram of Study Based Microcontroller (PIC18F2550) 55 3.9 PIC18F2550 Pin out I/O Descriptions 56 3.10 Memory Organization 60 3.10.1 Program 60 3.10. 2 Data Memory Organization 61 3.10.3 Data EEPROM Memory 62 3.10.3.1 EECON1 and EECON2 Registers 62

CHAPTER-4

DIGITAL ENERGY METER 4.1 Introduction 64 4.2 Circuit Diagram and Operation of Digital Energy Meter 65 4.3 General Description and Functional Block Diagram of ADE7756 66 4.4 Analog Input 68 4.5 Active Power Calculation 70 4.6 Energy Calculation 73 4.7 Energy Calibration 75 4.8 Analog to Digital Conversion 76 4.9 Calibrating the Energy Meter 78 4.9.1 Calculating the Average Active Power 78 4.9.2 Calibrating the Frequency at CF 79

CHAPTER-5 DESIGN AND DEVELOPMENT OF MICROCONTROLLER BASED ENERGY

METER SYSTEM 5.1 Introduction 80 5.2 Block Diagram and Description of Each Block 80 5.3 Work Flow Chart 82 5.4 Program Flow Chart 83 5.5 Interfacing Circuit 84

5.5.1 Interfacing Circuit between Microcontroller and GSM Module 84

x

5.5.2 Interfacing Circuit between GSM Module and GSM Network.

86

5.5.3 Interfacing Circuit Between Microcontroller and Digital Energy Measuring Chip

86

5.5.4 Interfacing Circuit Between Microcontroller and Liquid Crystal Display

87

5.5.5 Interfacing Circuit Between GSM Module and SIM 88 5.6 Power Supply Unit 88 5.6.1 Switched-Mode Power Supply 89 5.6.2 Study Base Power Supply Unit 89 5.7 Feature of Study Base Microcontroller ( PIC18F2550 ) 90 5.8 GSM Module 91 5.8.1 Pin Diagram of Study Base GSM Module (SIM300CZ) 92 5.8.2 Features of GSM Module SIM 300CZ 93 5.8.3 Functional Diagram of GSM Module SIM 300CZ 95 5.8.4 Top view of GSM Module SIM 300CZ 96

5.8.5 Bottom view of GSM Module SIM 300CZ 96 5.8.6 Operating Modes of GSM Module SIM 300CZ 97 5.8.7 Pin Descriptions of GSM Module 97 5.9 Pin Description of the SIM Card 98 5.10 SIM Card Holder 98 5.11 Liquid Crystal Display 99 5.12 Outline of LCD Module 100 5.13 PICBASIC AND PICBASIC PRO Compilers 101 5.13.1 Comparison Between PICBASIC and PICBASIC PRO 102 5.13.2 Additional commands available only in PICBASIC 102 5.13.3 PICBASIC PRO advantages 103 5.13.4 PICBASIC PRO Compiler Instruction Set 103 5.13.5 Functions / Operators 105 5.13.6 Structure of a Compiled Program 106 5..13.7 Target Specific Headers 106 5..13 8 The Library Files 106 5.13.9 PBP Generated Code 107 5.13.10 ASM File Structure 107 5. 14 EPIC Programmer 107

5.14.1

EPIC Programmer for PIC micro controllers features 108 5.14.2 EPICWIN and EPIC Programmer 108 5.14.2.1 Software Installation 108 5.14.2.2 Hardware Installation 108 5.14.3 General Operation 109 5.14.4 EPIC for Windows 95/98/ME/NT/2000/XP 109 5.14.5 EPIC Win Controls 110 5.14.6 EPIC Win Menus 111 5.14.6.1 File Menu 111 5.14.6.2 View Menu 111 5.14.6.3 Run Menu 112 5.14.6.4 Configuration Menu 112 5.14.6.5 Options Menu 112 5.15 In-Circuit Serial Programming 113 5.16 Photograph /Bottom view/Layout of the System 114

xi

CHAPTER-6 RESULT AND VERIFICATION

6.1 Objectives 116 6.2 Required Equipment 116 6.2.1 Hardware Components 116 6.2.2 Software Components 116 6.3 Circuit Diagram 117 6.4 Operation 118

6.5 Result 119 6.6 Discussion 119

CHAPTER-7 ENERGY METER READING TRANSFER TO BILLING STATION

7.1 Introduction 120 7.2 System Architect of Energy Meter Reading Save into Database Server 120 7.3 Server Software used for Processing the Energy Meter

Reading into Database 121

7.4 Utility of SMS Enabler Software for processing the Energy Meter Reading.

121

7.5 Key Feature of SMS Enabler Software 121 7.6 Utility of SQL for Reformatting the Energy Meter Reading Data

into Database Server 122

7.6.1 Query of Structured Query Language 122 7.7 Method of Loading Energy Meter Reading into a Database

Server using SMS Enabler Software. 123

7.8 Transfer Data from Database Server-1 to Database Server-2 Using SQL (Structured Query Language).

125

CHAPTER-8 DISCUSSION

8.1 Limitation 127 8.2 Achievement 128 8.3 Recommendation for Future Work 128

REFERENCES 129 APPENDICES 131

PUBLICATION 132 Program used in the device I-IV

xii

LIST OF TABLES

Table. 3.1 Pin Out I/O Description of PICF18 2550 Microcontroller 56 Table. 5.1 Feature of Study Base Microcontroller( PIC18F2550 ) 90 Table. 5.2 Features of GSM Module SIM 300CZ 93 Table. 5.3 Operating Modes of GSM Module 97 Table. 5.4 Pin Functions of GSM Module 97 Table. 5.5 Pin Functions of the SIM Card 98 Table. 5.6 Comparison Between PICBASIC and PICBASIC PRO Compilers 102 Table. 5.7 Various operators and Functions 105 Table. 7.1 Format of Database server 123 Table.7.2 Energy Meter Reading Load into Database server-1 126 Table.7.3 Energy Meter Reading Load into Database server-2 126

xiii

LIST OF FIGURES

Fig. 1.1: The Remote Metering System 4 Fig .1.2: Block Diagram of the Remote Meter 4 Fig. 1.3: Block Diagram of the Central Server 6 Fig.1. 4: Communication between the Central Server and the Remote Meter 7 Fig. 2.1: SMS Protocol Stack 22 Fig. 2.2: Simplified SMS Reference Model 23 Fig. 2.3: Represent the Working Mechanism of SMS System 24 Fig. 2.4: GSM Network Architecture 29 Fig. 2.5: Transfers of GSM Subscription Data for a Roaming Subscriber 31 Fig. 2.6: Components of the Mobile Station 34 Fig. 2.7: Structure of the IMSI 34 Fig.2.8: Structure of MSISDD 35 Fig.2.9: Structure of IMEI and IMEISV 36 Fig. 2.10: Usage of MSRN during call establishment to a GSM subscriber 37 Fig. 3.1: Main components of a microcontroller 41 Fig. 3.2: Microcontroller ROM/RAM 43 Fig. 3.3: Microcontroller I/O ports 45 Fig. 3.4: Block Diagram of PIC18F2550 Microcontroller 54 Fig.3.5: P in Diagram of the PIC18F2550 Microcontroller 55 Fig: 3.6: Program Memory Map and Stack for PIC18F2550 Device 60 Fig. 3.7: Data Memory Map for PIC18F2550 Device 61 Fig. 3.8: EECON1 Data EEPROM Control Registers 63 Fig.4.1: Circuit Diagram of Digital Energy Meter 65 Fig.4.2: Functional Block Diagram of ADE7756 67 Fig.4.3: Analog Gain Resister 68 Fig.4.4: PGA in Channel 69 Fig. 4.5: Effect of Channel Offsets on the Real Power Calculation 70 Fig.4.6: Active Power Calculation 71 Fig. 4.7: Frequency Response of LPF 72 Fig. 4.8: Active Power Signal Processing 73 Fig. 4.9: Active Power Calculation Output Range 73 Fig4.10 : Energy Calculations 74 Fig. 4.11:

Energy Calculations in Calibration Mode 75 Fig. 4.12: First Order Sigma Delta ADC 76 Fig. 4.13: Noise Reduction Due to over sampling and Noise Shaping in the Analog Modulator

77

Fig. 5.1: Block Diagram of the System 81 Fig. 5.2: Work Flow Chart 82 Fig. 5.3: Program Flow Chart of the System 83 Fig. 5.4(a): Interfacing Circuit between GSM Module and Microcontroller 84 Fig.5.4(b): Interfacing Circuit between GSM Module and Microcontroller 85 Fig.5.4(c): Interfacing Circuit between GSM Module and Microcontroller 85 Fig. 5.5 : Interfacing Circuit between GSM Module and GSM Network. 86 Fig. 5.6 : Interfacing circuit Between Microcontroller and Digital Energy Meter 87 Fig. 5.7 : Interfacing Circuit Between Microcontroller and Liquid Crystal Display 87 Fig. 5.8: Interfacing Circuit Between GSM Module and SIM 88 Fig. 5.9: Study Base Power Supply Unit 89

xiv

Fig. 5.10: GSM ModuleSIM300CZ Pin configuration 92 Fig. 5.11: Functional Diagram of GSM Module SIM 300CZ 95 Fig. 5.12: Top view of GSM Module SIM300CZ 96 Fig. 5.13: Bottom view of GSM Module SIM300 CZ 96 Fig. 5.14: Diagram of the SIM Card Holder 98 Fig. 5.15: Reflective Twisted Nematic Liquid Crystal Display 99 Fig. 5.16: In-Circuit Serial Programming 113 Fig. 5.17(a):

Front Photograph of the Prototype in functional state

114 Fig. 5.17(b): Bottom View of the System 115 Fig. 6.1: Schematic circuit Diagram 117 Fig. 7.1: Block Diagram of the System 120

xv

List of Abbreviations AUC. Authentication Centre ALU Arithmetic Logic Unit ADC Analog to Digital Converter BSS Base Station System BTS Base Transiver Station BSC Base Station Controller BS Base Station BSS Base Station System BSSAP Base Station System Application Part CDMA Code Division Multiple Access DEM Digital Energy Meter DAC Digital to Analog Converter DTAP Direct Transfer Application Part DTR Data Terminal Ready EPROM Electrical Programmable Read Only Memory EEPROM Electrically Erasable Programmable Read Only Memory FSR File Select Resister GSM Global System for Mobile Communication GMSC Gateway Mobile Switching Center GPR General Purpose Register HLR Home Location Register HPF High Pass Filter IR Instruction Register LCD Liquid Crystal Display LPF Low Pass Filter MMS Multimedia Messaging Service MS Mobile Station MAP Mobile Application Part MSC Mobile Switching Center PIC Peripheral Interface Controller PGA Programmable Gain Amplifier RAM Random Access Memory ROM Read Only Memory SMS Short Message Service SME Short Message Entity SIM Subscriber Identification Module SMSC Short Message Service Centre SFR Special Function Register TDMA Time Division Multiple Access TE Terminal Equipment VMSC Visited Mobile Switching Center VLR Visitor Location Register USB Universal Synchronous Bussss

Introduction 1

CHAPTER-1

INTRODUCTION

1.1 Back Ground of the Work

From view point of Bangladesh, for conventional electrical energy measurements only analog

energy metering system was available and on the basis of analog energy meter reading

system the whole billing system would be completed. There follows a number of measuring

system in which the degree of accuracy cannot be fully assured, that means, measured value

may be more or less with respect to actual consumption. In that case either organization or

consumer falls in trouble. But now a day’s in addition to analog energy meter, post paid and

prepaid digital energy metering systems are available in Bangladesh. The measurement

accuracy of digital meter is much better than analog meter but it is somewhat costly and

sensitive. In both cases, therefore, analog energy meter system and digital energy meter

system, a meter reader has to be attended for taking the reading at the end of month or

specific date. Sometimes due to shortage of man power, anomalous weather and

communication, the electrical power supply organization can not take the meter reading

timely. Under these circumstances chance of corruption on meter reading system affects the

organization in the form of system loss. Only for meter reading purpose, the power supply

organization has to employ a lot of meter readers which incurs a huge cost. Sometimes the

meter readers along with the consumers are involved with corruption which ultimately causes

massive loss affecting the power supply organization. This leads to have an impact on

consumers. The corruption of meter readers and consumers are evaluated as system loss that

reflects as interruption of national development. The advancement of technology contributes

towards the development of digital energy meter which has been gradually replacing analog

energy meters all over the world.

The prepaid energy meter system exists in Dhaka, Chittagong, Bogra and Sirajgong districts.

In case of prepaid energy meter reading system, the consumer has to purchase meter card

from the market or organization and install into the metering system. When the book value of

the meter card is finished by the consumption of electrical energy, the meter automatically

shuts down and for the time being consumer faces trouble of load shedding.

The service of mobile telecommunication systems is increasing day by day. Now it is

possible to send the message from one place to another within a moment by the endorsement

of mobile telecommunication systems with minimum cost that was in earlier, it would need

enormous amount of time and cost for performing the same work by the involvement of

GSM & SMS Technology 17

CHAPTER--2 GSM AND SMS TECHNOLOGY

2. 1 Introduction

Short message service is a mechanism of delivery of short messages over the mobile networks. It

is a store and forward way of transmitting messages to and from mobiles[15].The message (text

only) from the sending mobile is stored in a central “Short Message Service Center” (SMSC)

which then forwards it to the destination mobile. This means that in the case that the recipient is

not available, the short message is stored and can be sent later. Each short message can be no

longer than 160 characters. These characters can be text (alphanumeric) or binary Non-Text

Short messages. An interesting feature of SMS is return receipts. This means that the sender, if

wishes, can get a small message notifying if the short message was delivered to the intended

recipient. Since SMS used signaling channel as opposed to dedicated channels, these messages

can be sent/received simultaneously with the voice/data/fax service over a GSM network. SMS

supports national and international roaming. This means that we can send short messages to any

other GSM mobile user around the world. With the PCS networks based on all the three

technologies, GSM, CDMA and TDMA supporting SMS, SMS is more or less a universal

mobile data service. However, an SMS message can originate from an external system such as

e-mail or mobile device and is routed through the network, via the short messaging service center

(SMSC), to its destination. A distinguishing feature of SMS is its ability to deliver messages any

time, regardless of whether data or voice calls are in progress[17] .

2.2 SMS as a Part of GSM

2.2.1 Initial Concept

The idea of adding text messaging to the services of mobile users was latent in many

communities of mobile communication services at the beginning of the 1980s. The first action

plan of the CEPT Group GSM approved in December 1982 requested "The services and facilities

offered in the public switched telephone networks and public data networks ...should be available

in the mobile system". This target includes the exchange of text messages either directly between

mobile stations or the transmission via Message Handling Systems widely in use since the

beginning of the 1980s.


The innovation in SMS is indicated by the word Short in Short Message Service. The GSM

system is optimized for telephony, since this was identified as its main application. The key idea

for SMS was to use this telephony-optimized system and to transport messages on the signaling

paths needed to control the telephony traffic during time periods when no signaling traffic

existed. In this way unused resources in the system could be used to transport messages without

additional cost. However, it was necessary to limit the length of the messages to 128 bytes (later

improved to 140 bytes, or 160 7-bit characters), so that the messages could fit into the existing

signaling formats. Therefore the service was named “Short Message Service”. This concept

allowed implementing the SMS in every mobile station with additional software routines. A new

network element required was a specialized Short Message Service Centre, as well as

enhancement to the radio capacity and network transport infrastructure. It needed capacity

expansions of course with growing SMS traffic. This concept was instrumental for the

implementation of SMS in every mobile station ever produced and in every network from early

days on. Hence a large base of SMS capable terminals and networks existed when the users

began to utilize the SMS

2.2.2 Early Development

No individual expert or company can claim to be the ‘father’ or ‘creator’ of the SMS. The GSM

project as a whole was indeed a multi-national collaboration at its best. Therefore the

responsibility for the SMS innovation is not with a single person but with a network of closely

cooperating persons who have created this innovation. They did this with the supporting

framework of Standard Bodies and through these organizations made the technology freely

available to the whole world. This is described and supported by evidence in the following

sections. The first proposal for SMS which initiated the development of SMS in the group GSM

was made by a contribution of Germany and France into the GSM meeting in February 1985 in

Oslo This proposal was further elaborated in GSM subgroup WP1 Services (Chairman Martine

Alvernhe, France Telecom) based on a contribution from Germany. There were also initial

discussions in the subgroup WP3 network aspects chaired by Jan Audestad (Telenor). The result

was approved by the main group GSM in a document of June 85 which was distributed to

industry. The input documents on SMS had been prepared by Friedhelm Hillebrand (Deutsche

Telekom) with contributions from Bernard Ghillebaert (France Télécom). SMS was considered

in the main GSM group as a possible service for the new digital cellular system. In GSM


document "Services and Facilities to be provided in the GSM System", both mobile originated

and mobile terminated short messages appear on the table of GSM tele services.Here a

rudimentary description of the three services was given:

Short message Mobile Terminated (SMS-MT)/ Point-to-Point: the ability of a network to

transmit a Short Message to a mobile phone. The message can be sent by phone or by a

software application.

Short message Mobile Originated (SMS-MO)/ Point-to-Point: the ability of a network to

transmit a Short Message sent by a mobile phone. The message can be sent to a phone or

to a software application.

Short message Cell Broadcast.

The material elaborated in GSM and its subgroups WP1 was handed over in spring 1987 to a new

GSM body called IDEG (the Implementation of Data and Telemetric Services Experts Group), which

had its kickoff in May 1987 under the chairmanship of Friedhelm Hillebrand (German Telecom). The

technical standard known today was largely created by IDEG (later WP4) as the two

recommendations GSM 03.40 (the two point-to-point services merged together) and GSM 03.41 (cell

broadcast).WP4 created a drafting group message handling (DGMH) who was responsible for the

specification of SMS. It was chaired by Finn Throsby (Telenor). DGMH had about 5 to 8 participants

(Finn Throsby mentions as contributors Alan Cox of Vodafone). The first action plan mentions for

the first time the Technical Specification 03.40 “Technical realization of the Short Message Service”.

Responsible editor was Finn Throsby. The first draft of the technical specification was completed in

November of 1987A comprehensive description. The work on the draft specification continued in the

following few years, where Kevin Holley of Cell net (now O2) played a leading role. Besides the

completion of the main specification GSM 03.40 also the detailed protocol specifications on the

system interfaces needed to be complete

2.2.3 Early Implementation

The first SMS message was sent over the Vodafone GSM network in the United Kingdom on 3

December 1992, from Neil Papworth of Sema Group (now Airwide Solutions) using a personal

computer to Richard Jarvis of Vodafone using an Orbitel 901 handset. The text of the

messagewas "Merry Christmas" The first SMS typed on a GSM phone is claimed to have been

sent by Riku Pihkonen, an engineering student at Nokia, in 1993 The first commercial


deployment of a Short Message Service Centre (SMSC) was by Aldiscon (now Acision) with

TeliaSonera in Sweden in 1993, followed by Fleet Call (now Nextel) in the US, Telenor in

Norway[and BT Cellnet (now O2 UK)[ later in 1993.Initial growth was slow, with customers in

1995 sending on average only 0.4 messages per GSM customer per month. One factor in the

slow takeup of SMS was that operators were slow to set up charging systems, especially for

prepaid subscribers, and eliminate billing fraud which was possible by changing SMSC settings

on individual handsets to use the SMSCs of other operators over time, this issue was eliminated

by switch-billing instead of billing at the SMSC and by new features within SMSCs to allow

blocking of foreign mobile users sending messages through it. By the end of 2000, the average

number of messages reached 35 per user per month, and by Christmas Day 2006, over 205m

texts were sent in the UK alone. It is also alleged that the fact that roaming customers, in the

early days, rarely received bills for their SMSs after holidays abroad had a boost on text

messaging as an alternative to voice calls.

2.2.4 Text Messing Outside GSM

SMS was originally designed as part of GSM, but is now available on a wide range of networks,

including 3G networks. However, not all text messaging systems use SMS, and some notable

alternate implementations of the concept include J-Phone's SkyMail and NTT Docomo's Short

Mail, both in Japan. E-mail messaging from phones, as popularized by NTT Docomo's i-mode

and the, also typically use standard mail protocols such as SMTP over TCP/IP.

2.2.5 SMS Today

Commercially SMS is a massive industry in 2006 worth over 81 billion dollars globally. SMS

has an average global price of 0.11 USD while costing providers almost nothing. Mobile

networks charge each other so-called interconnect fees of at least £0.03 when connecting

between different phone networks.

2.2.6 Message Size

Transmission of short messages between the SMSC and the handset is done whenever using the

Mobile Application Part (MAP) of the SS7 protocol. Messages are sent with the MAP mo- and

mt- Forward SM operations, whose payload length is limited by the constraints of the signaling

protocol to precisely 140 octets (140 octets = 140 * 8 bits = 1120 bits). Short messages can be


encoded using a variety of alphabets: the default GSM 7-bit alphabet the 8-bit data alphabet, and

the 16-bit UTF-16 alphabet.[27] Depending on which alphabet the subscriber has configured in

the handset, this leads to the maximum individual Short Message sizes of 160 7-bit characters,

140 8-bit characters, or 70 16-bit characters (including spaces). Support of the GSM 7-bit

alphabet is mandatory for GSM handsets and network elements but characters in languages such

as Arabic, Chinese, Korean, Japanese or Cyrillic alphabet languages (e.g. Russian, Serbian,

Bulgarian, etc) must be encoded using the 16-bit UTF-16 character encoding Routing data and

other metadata is additional to the payload size. Larger content (Concatenated SMS, multipart or

segmented SMS or "long sms") can be sent using multiple messages, in which case each message

will start with a user data header (UDH) containing segmentation information. Since UDH is

inside the payload, the number of characters per segment is lower: 153 for 7-bit encoding, 133

for 8-bit encoding and 67 for 16-bit encoding. The receiving handset is then responsible for

reassembling the message and presenting it to the user as one long message. While the standard

theoretically permits up to 255 segments, 6 to 8 segment messages are the practical maximum,

and long messages are often billed as equivalent to multiple SMS messages.. Some providers

have offered length-oriented pricing schemes for SMSs, however, the phenomenon is

disappearing.

2.3 SMS Protocols

Figure 2.1shows a simplified view of the network carrying SMS, including only a single SMS

message relay point. In principle any number of relay points could be included, each containing

an SMS protocol stack similar to that shown for the base station. For example, during a call that

has undergone an intersystem handoff, SMS messages arriving at the mobile station’s anchor

base station must be forwarded to the current serving base station for delivery [18]. The SMS

bearer service is the portion of the SMS system responsible for delivery of messages between the

MC and mobile user equipment. The bearer service is provided by the SMS Transport Layer and

the SMS Relay Layer. The SMS Transport Layer is the highest layer of the bearer service

protocol. The Transport Layer manages the end-to-end delivery of messages. In an entity serving

as a relay point, the Transport Layer is responsible for receiving SMS Transport Layer messages

from an underlying SMS Relay Layer, interpreting the destination address and other routing

information, and forwarding the message via an underlying SMS Relay Layer.


Fig. 2.1: SMS Protocol Stack

2.4 Network Reference Model for SMS

Figure 2.2 contains the network reference model for SMS. This model presents functional

entities and associated interface reference points that may logically comprise a wireless network.

The model is intended to provide a level of abstraction that facilitates the specification of

messages within TIA/EIA-637-A. As such, implementations may vary with respect to how the

functional entities are distributed among physical units The base station (BS) in this model

contains the transceiver equipment, Mobile Switching Center (MSC) and any Inter-Working

Function (IWF) required for network connection. These


Fig. 2.2: Simplified SMS Reference Model

elements are grouped together because there is no need to distinguish them in this standard. The

MC element in this model represents a generic SMS Message Center function. The N reference

point represents one or more standardized interfaces between an SMS message center and a BS.

The Terminal Equipment (TE) is voice or data equipment connected either directly or indirectly

to the MC[18]. It is possible for the MC to be included in, or co-located with, a base station. In

this case, the N Interface is internal to the base station. For purposes of this standard, the

19proceduresdefined for the N Interface should be followed for such internal interfaces.

2.5 How Does SMS Work

The figure 2.3 shows a typical organization of network elements in a GSM network supporting

SMS. The SMC (Short Message Center) is the entity which does the job of store and forward of

messages to and from the mobile station. The SME (Short Message Entity) which can be located

in the fixed network or a mobile station receives and sends short messages [18].


Fig. 2.3: Represent the Working Mechanism of SMS System

. The gateway MSC is a mobile network’s point of contact with other networks. On receiving the

short message from the short message center, GMSC uses the SS7 network to interrogate the

current position of the mobile station form the HLR, the home location register. HLR is the main

database in a mobile network. It holds information of the subscription profile of the mobile and

also about the routing information for the subscriber, i.e. the area (covered by a MSC) where the

mobile is currently situated. The GMSC is thus able to pass on the message to the correct MSC.

MSC (Mobile Switching Center) is the entity in a GSM network which does the job of switching

connections between mobile stations or between mobile stations and the fixed network A VLR

(Visitor Location Register) corresponds to each MSC and contains temporary information about

the mobile, information like mobile identification and the cell (or a group of cells) where the

mobile is currently situated. Using information form the VLR the MSC is able to switch the

information (short message) to the corresponding BSS (Base Station System, BSC + BTSs),

which transmits the short message to the mobile. The BSS consists of transceivers, which send

and receive information over the air interface, to and from the mobile station. This information is


passed over the signaling channels so the mobile can receive messages even if a voice or data

call is going on.

2.6 Benefit of SMS

SMS first appeared in Europe in 1991 as part of the Global System for Mobile Communications

(GSM) Phase 1 standard. SMS was made available in North America recently, and was first

adopted on digital networks built by early wireless carriers such as BellSouth Mobility, Nextel,

and AT&T. SMS is supported on digital wireless networks based on GSM, code division

multiple access (CDMA), and time division multiple access (TDMA). SMS has a number of

benefits, which include [17]

Guaranteed delivery of notifications and alerts to single or multiple users.

Increased user productivity through instant delivery of notifications and alerts.

Low cost and reliable communication mechanism for information delivery.

Integration with Internet-based applications.

Another service and source of revenue for service providers.

Very possible replacement of existing two-way paging.

2.7 Application of SMS

Some of the common applications of SMS are: [15]

Exchanging small messages like " xyz". SMS is particularly suited for these kinds of short

messages because SMS is much cheaper than calling some one and giving the same message.

Calling some one to give the same message would invariably take more time and hence more

cost.

Many operators offer e-mail service over SMS. Every user is assigned an e-mail address at

signup and any message delivered to that email is converted to short messages and delivered

to the mobile.

It is possible to send e-mail messages (less than 160 characters) from a mobile phone to any

e-mail address via SMS.

Information services like news, weather, entertainment and stock prices etc. can be availed

just by sending a keyword like NEWS, WEATH etc to the short message center number.


SMS can be used by the network operators to provide services like balance enquiry in case of

prepaid cards using SMS.

Mobile chatting is one more hot application of SMS

SMS can be used to notify users that they have received new voice-mail or fax messages.

It provides an alternative to alphanumeric paging services

Using SIM-Toolkit, now a part of GSM specifications, SMS can be used to have on the air

activation of features. By sending codes embedded in short messages from the server

network operators can remotely provision the user's wireless terminal

Internet e-mail alerts.

Downloading new ring tones.

2.8 Limitation of SMS

There is no doubt that SMS has been very popular. The figures in the section above support this.

What is more interesting to observe is that this popularity has been inspire of many limitations of

SMS. Many of these limitations are the driving force behind the developments and initiatives

being taken in the field of short messaging. Some of the limitations of SMS are:

Messages are plain vanilla in nature. We can only send simple text messages. There is no

scope for any graphics or audio.

The messages are limited by size. An SMS message can’t exceed 160 characters. (BTW this

limitation is due to the limitation in the MAP protocol in GSM) In case of longer e-mails or

information service messages like news, the messages need to broken down into more than

one message. The need to break the messages into several smaller segments could make SMS

comparatively costlier in comparison to GPRS (for the same kind of service). Also, This

doesn’t look very appealing on a mobile device.

The limitation of easy input mechanisms in mobile devices makes it very uncomfortable

sending messages larger than even 5-6 words.

However Predictive text input algorithms implemented in a mobile phone can greatly help.

Voice recognition systems can further help ease the situation


Many proprietary protocols are used by SMS operators and application developers need to

implement different interfaces for making their applications work with different SMS

centers. X.25 is used as a popular protocol for connecting with SMS centers

SMS protocol data units as defined in GSM 03.40 are also not very efficient. The various

header fields in the PDU are fixed which puts a constraint on the scenarios that can be

indicated. 3G specifications are being looked up to look and address these constraints

The store and forward nature of SMS, though useful in many applications makes SMS not

very suitable for WAP.

2.9 Initiatives and Future Developments of SMS

SMS is a first generation GSM service. SMS has some inherent limitations. The majority of

these are to do with the fact that SMS is plain vanilla in nature. Enhanced Messaging Service

(EMS) is a mechanism by which we can send a comparatively richer message that are

combination of text, simple melodies, pictures (simple, black and white) and animations to an

EMS compliant handset. The service is very much based on the existing SMS. It basically

extends the User Data Header (UDH) in SMS (UDH makes it possible to include binary

information in the message header) and in fact needs no upgrade to the network infrastructure.

The handsets however need to be EMS compliant. The first EMS handsets should be available by

mid of 2001 [12]. The next step in the evolution of SMS, which requires substantial changes in

the network infrastructure, is the Multimedia Messaging Service (MMS) that allows a

combination of text, sounds, images and video. MMS will support pictures and interactive video.

It will be possible, for example, to send mobile greeting cards and visiting cards using MMS.

MMS uses standardized protocols like WAP, MExE and SMTP. While EMS requires content

reformatting for mobile devices, there is no such requirement for MMS. Theoretically MMS may

run on any bearer service, but practically it would require GPRS or 3G bearer services before it

starts appearing. AS opposed to SMS, MMS needs a dedicated channel. It would also require

new network elements like Multimedia Messaging Relays, MMS Server and MMS User

Databases. While MMS trials have been planned in mid 2001, the first MMS compliant handsets

are expected to hit the market only in end 2002. MMS is being standardized by the 3GPP


According to 3GPP standards MMS is a new service, which has no direct equivalent in the

previous ETSI/GSM world or in the fixed network world.

2.10 Description of GSM Network

Figure 2.4 is a schematic overview of the main components in a GSM network. The GSM

network consists mainly of the following functional parts:

MSC – the mobile service switching centre (MSC) is the core switching entity in the

network. The MSC is connected to the radio access network (RAN); the RAN is formed by

the BSCs and BTSs within the Public Land Mobile Network (PLMN). Users of the GSM

network are registered with an MSC; all calls to and from the user are controlled by the

MSC. A GSM network has one or more MSCs, geographically distributed.

VLR – the visitor location register (VLR) contains subscriber data for subscribers registered

in an MSC. Every MSC contains a VLR. Although MSC and VLR are individually

addressable, they are always contained in one integrated node.

GMSC – the gateway MSC (GMSC) is the switching entity that controls mobile

terminating calls. When a call is established towards a GSM subscriber, a GMSC contacts

the HLR of that subscriber, to obtain the address of the MSC where that subscriber is

currently registered. That MSC address is used to route the call to that subscriber [19].

HLR – the home location register (HLR) is the database that contains a subscription record

for each subscriber of the network. A GSM subscriber is normally associated with one

particularly. The HLR is responsible for the sending of subscription data to the VLR

(during registration) or GMSC (during mobile terminating call handling).

CN – the core network (CN) consists of, amongst other things, MSC(s), GMSC(s) and

HLR(s).These entities are the main components for call handling and subscriber

management. Other main entities in the CN are the equipment identification register (EIR)

and authentication centre (AUC). CAMEL has no interaction with the EIR and AUC; hence

EIR and AUC are not further discussed.

BSS – the base station system (BSS) is composed of one or more base station controllers

(BSC)and one or more base transceiver stations (BTS). The BTS contains one or more

transceivers (TRX). The TRX is responsible for radio signal transmission and reception.


BTS and BSC are connected through the Abis interface. The BSS is connected to the MSC

through the A interface.

MS – the mobile station (MS) is the GSM handset.

A GSM network is a public land mobile network (PLMN). Other types of PLMN are the time

division multiple access (TDMA) network or code division multiple access (CDMA) network’s

uses the following sub-division of the PLMN:

Fig. 2.4: GSM Network Architecture

Home PLMN (HPLMN) – the HPLMN is the GSM network that a GSM user is a

subscriber of. That implies that GSM user’s subscription data resides in the HLR in that

PLMN. The HLR may transfer the subscription data to a VLR (during registration in a

PLMN) or a GMSC (during mobile terminating call handling). The HPLMN may also

contain various service nodes, such as a short message service centre (SMSC), service

control point (SCP), etc.

Visited PLMN (VPLMN) – the VPLMN is the GSM network where a subscriber is

currently registered. The subscriber may be registered in her HPLMN or in another

PLMN. In the latter case, the subscriber is outbound roaming (from HPLMN’s

perspective) and inbounds roaming (from VPLMN’s perspective). When the subscriber

is currently registered in her HPLMN, then the HPLMN is at the same time VPLMN.1


Interrogating PLMN (IPLMN) – the IPLMN is the PLMN containing the GMSC that

handles mobile terminating (MT) calls. MT calls are always handled by a GMSC in the

PLMN, regardless of the origin of the call. For most operators, MT call handling is

done by a GMSC in the HPLMN; in that case, the HPLMN is at the same time IPLMN.

This implies that calls destined for a GSM subscriber are always routed to the HPLMN

of that GSM subscriber. Once the call has arrived in the HPLMN, the HPLMN acts as

IPLMN. MT call handling will be described in more detail in subsequent sections.

When basic optimal routing (BOR) is applied, the IPLMN is not the same PLMN as the

HPLMN.

2.11 Signaling in GSM

The various entities in the GSM network are connected to one another through signaling

networks. Signaling is used for example, for subscriber mobility, subscriber registration, call

establishment, etc. The connections to the various entities are known as ‘reference points’.

Examples include:

A interface – the connection between MSC and BSC;

Abis interface – the connection between BSC and BTS;

D interface – the connection between MSC and HLR;

Um interface – the radio connection between MS and BTS.

Various signaling protocols are used over the reference points. Some of these protocols for

GSM are the following:

Mobile Application Part (MAP) – MAP is used for call control, subscriber registration,

short

Message Service, etc.; MAP is used over many of the GSM network interfaces;

Base Station System Application Part (BSSAP) – BSSAP is used over the A interface;

Direct Transfer Application Part (DTAP) – DTAP is used between MS and MSC;

DTAP is carried

Over the Abis and the A interface.

ISDN user part (ISUP) – ISUP is the protocol for establishing and releasing circuit

switched calls. ISUP is also used in landline Integrated Services Digital Network

(ISDN). A circuit is the data channel that is established between two users in the


network. Within ISDN, the data channel is generally a 64 kbit/s channel. The circuit is

used for the transfer of the encoded speech or other data [19].

When it comes to call establishment, GSM makes a distinction between signaling and payload.

Signaling refers to the exchange of information for call set up; payload refers to the data that is

Transferred within a call, i.e. voice, video, fax etc. For a mobile terminated GSM call, the

signaling consists of exchange of MAP messages between GMSC, HLR and visited MSC

(VMSC). The payload is transferred by the ISUP connection between GMSC and VMSC. It is

a continual aim to optimize the payload transfer through the network, as payload transfer has a

direct cost aspect associated with it. Some network services are designed to optimize the

payload transfer. One example is optimal routing.

2.12 GSM Mobility

Roaming with GSM is made possible through the separation of switching capability and

subscription data..

Fig. 2.5: Transfers of GSM Subscription Data for a Roaming Subscriber

A GSM subscriber has her subscription data, including CAMEL data, permanently registered in

the HLR in her HPLMN. The GSM operator is responsible for provisioning this data in the HLR.

The MSC and GMSC in a PLMN, on the other hand, are not specific for one subscriber group


The switching capability of the MSC in a PLMN may be used by that PLMN’s own subscribers,

but also by inbound roaming subscribers; shows Figure2.5.In Figure 2.5, the GSM user who is a

subscriber of PLMN-A roams to PLMN-B. The HLR in PLMN-A transfers the user’s

subscription data to the MSC in PLMN-B. The subscriber’s subscription data remains in the

MSC/VLR as long as she is served by a BSS that is connected to that MSC. Even when the user

switches her MS off and then on again, the subscription data remains in the MSC. After an

extended period of the MS being switched off, the subscription data will be purged from the

MSC. When the subscriber switches her MS on again, the subscriber has tore-register with the

MSC, which entails the MSC asking the HLR in the HPLMN to re-send the subscription data for

that subscriber When the subscriber moves from one MSC service area (MSC-1) to another MSC

service area(MSC-2), the HLR will instruct MSC-1 to purge the subscription data of this

subscriber and will send the subscription data to MSC-2.

2.13 The GSM Specifications

Specifications for different Personal Communication Services (PCS) systems vary among the

different PCS networks. The GSM specification is listed below with important characteristics.

2.13.1 Modulation

Modulation is a form of change process where we change the input information into a suitable

format for the transmission medium. We also changed the information by demodulating the

signal at the receiving end. The GSM uses Gaussian Minimum Shift Keying (GMSK)

modulation method.

2.13.2 Access Methods

Because radio spectrum is a limited resource shared by all users, a method must be devised to

divide up the bandwidth among as many users as possible. GSM chose a combination of

TDMA/FDMA as its method. The FDMA part involves the division by frequency of the total 25

MHz bandwidth into 124 carrier frequencies of 200 kHz bandwidth. One or more carrier

frequencies are then assigned to each BS. Each of these carrier frequencies is then divided in

time, using a TDMA scheme, into eight time slots. One time slot is used for transmission by the

mobile and one for reception. They are separated in time so that the mobile unit does not receive

and transmit at the same time.


2.13.3 Transmission Rate:

The total symbol rate for GSM at 1 bit per symbol in GMSK produces 270.833 K

symbols/second. The gross transmission rate of the time slot is 22.8 Kbps. GSM is a digital

system with an over-the-air bit rate of 270 kbps.

2.13.4 Frequency Band

The uplink frequency range specified for GSM is 935 - 960 MHz (basic 900 MHz band only).

The downlink frequency band 890 - 915 MHz (basic 900 MHz band only).

2.13.5 Channel Spacing

This indicates separation between adjacent carrier frequencies. In GSM, this is 200 kHz.

2.13.6 Speech Coding:

GSM uses linear predictive coding (LPC). The purpose of LPC is to reduce the bit rate. The LPC

provides parameters for a filter that mimics the vocal tract. The signal passes through this filter,

leaving behind a residual signal. Speech is encoded at 13 kbps.

2.13.7 Duplex Distance:

The duplex distance is 70 MHz. Duplex distance is the distance between the uplink and downlink

frequencies. A channel has two frequencies, 70 MHz apart.

2.14 Identifier in GSM Network

GSM uses several identifiers for the routing of calls, identifying subscribers (e.g. for charging),

Locating the HLR, identifying equipment, etc. Some of these identifiers play an important role

for CAMEL.

:2.14. 1 International Mobile Subscriber Identity

The international mobile subscriber identity (IMSI) is embedded on the SIM card and is used to

identify a subscriber. The IMSI is also contained in the subscription data in the HLR. The IMSI


Fig. 2.6: Components of the Mobile Station

used for identifying a subscriber for various processes in the GSM network. Some of these are:

Fig. 2.7: Structure of the IMSI

Location Update – when attaching to a network, the MS reports the IMSI to the MSC,

which uses the IMSI to derive the global title (GT) of the HLR associated with the

Terminating Call – when the GSM network handles a call to a GSM subscriber, the HLR

uses the IMSI to identify the subscriber in the MSC/VLR, to start a process for delivering

the call to that subscriber in that MSC/VLR.


Roaming Charging – a VPLMN uses the IMSI to send billing records to the HPLMN of a

subscriber Figure: 2.7 shows the format of the IMSI.

Mobile Country Code (MCC) – the MCC identifies the country for mobile networks. The

MCC is not used for call establishment.

Mobile network code (MNC) – the MNC identifies the mobile network within a mobile

country (as identified by MCC). MCC and MNC together identify a PLMN. The MNC

may be two or three digits in length. Common practice is that, within a country (as

identified by MCC), all MNCs are either two or three digits.

Mobile subscriber identification number (MSIN) – the MSIN is the subscriber identifier

within a PLMN. The IMSI is reported to the SCP during CAMEL service invocation. The

IMSI may be needed, for example, when identifying a country; countries in North

America have equal country code (country code = 1), but different MCC (e.g. Canada =

303; Mexico = 334).

2.14. 2 Mobile Station Integrated Service Digital Network Number

The MSISDN is used to identify the subscriber when, among other things, establishing a call to

that subscriber or sending an SMS to that subscriber.

Fig. 2.8: Structure of MSISDD


Hence, the MSISDN is used for routing purposes. The is not stored on the subscriber’s SIM card

and is normally not available in the MS.2 The MSISDN is provisioned in the HLR, as part of the

subscriber’s profile, and is sent to MSC during registration. The MSISDN is also reported to

SCP when a CAMEL service is invoked. One subscriber may have multiple MSISDNs. These

MSISDNs are provisioned in the HLR. At any one moment, only a single MSISDN is available

in the MSC/VLR for the subscriber.

2.14.3 International Mobile Equipment Identifier

The international mobile equipment identifier (IMEI) is used to identify the ME [or user

equipment (UE) in UMTS network.

Fig.2.9: Structure of IMEI and IMEISV . Each ME has a unique IMEI. The IMEI is hard-coded in the ME and cannot be modified.

Figure 2.9 shows the structure of the IMEI and IMEISV. The IMEI is not used for routing or

subscriber identification.


2.14.4 Mobile Station Roaming Number

The mobile station roaming number (MSRN) is used in the GSM network for routing a call to a

MS. The need for the MSRN stems from the fact that the MSISDN identifies a subscriber, but

not the current location of that subscriber in a telecommunications network. The MSRN is

allocated to a subscriber during MT call handling and is released when the call to that subscriber

is established. Each MSC in a PLMN has a (limited) range of MSRNs allocated to it. An MSRN

may be allocated to any subscriber registered in that MSC. The MSRN has the form of an E.164

number and can be used by the GMSC for establishing a call to a GSM subscriber. An MSRN is

part of a GSM operator’s number plan. The MSRN indicates the GSM network a subscriber is

registered in, but not the GSM network the subscriber belongs to. Figure 3.10 shows how the

MSRN is used for call that subscribers cannot dial numbers that fall within the MSRN range of

that operator[16].

Fig. 2.10: Usage of MSRN during call establishment to a GSM subscriber

2.15 GSM User Services

GSM has much more to offer than voice telephony. Additional services allow greater flexibility

in where and when use phone. We should contact local GSM network operator for information

on the specific services available. But there are three basic types of services offered through

GSM which can ask for [19]


Telephony (also referred to as teleservices) Services

Data (also referred to as bearer services) Services.

Supplementary Services

2.15.1 Tele services

A Teleservice utilizes the capabilities of a Bearer Service to transport data, defining which

capabilities are required and how they should be set up.

2.15. 2 Voice Calls

The most basic Teleservice supported by GSM is telephony. This includes Full-rate speech at 13

Kbps and emergency calls, where the nearest emergency service provider is notified by dialing

three digits. A very basic example of emergency service is 911 services available in USA.

2.15.3 Videotext and Facsimile:

Another group of teleservices includes Videotext access, Teletex transmission, Facsimile

alternate speech and facsimile Group 3, Automatic facsimile Group 3 etc.

2.15.4 Short Text Messages:

SMS (Short Messaging Service) service is a text messaging which allow us to send and receive

text messages on our GSM Mobile phone. Services available from many of the world's GSM

networks today - in addition to simple user generated text message services - include news, sport;

financial, language and location based services, as well as many early examples of mobile

commerce such as stocks and share prices, mobile banking facilities and leisure booking

services.

2.15.5 Bearer Services or Data Services

Using our GSM phone to receive and send data is the essential building block leading to

widespread mobile Internet access and mobile data transfer. GSM currently has a data transfer

rate of 9.6k. New developments that will push up data transfer rates for GSM users are HSCSD

(high speed circuit switched data) and GPRS (general packet radio service) are now available.


2.15.6 Supplementary Services

Supplementary services are provided on top of teleservices or bearer services, and include

features such as caller identification, call forwarding, call waiting, multiparty conversations, and

barring of outgoing (international) calls, among others. A brief description of supplementary

services is given here:

Multiparty Service or conferencing: The multiparty service allows a mobile subscriber

to establish a multiparty conversation. that is, a simultaneous conversation between three

or more subscribers to setup a conference call. This service is only applicable to normal

telephony.

Call Waiting: This service allows a mobile subscriber to be notified of an incoming call

during a conversation. The subscriber can answer, reject, or ignore the incoming call.

Call waiting is applicable to all GSM telecommunications services using a circuit-

switched connection.

Call Hold: This service allows a subscriber to put an incoming call on hold and then

resume this call. The call hold service is only applicable to normal telephony.

Call Forwarding: The Call Forwarding Supplementary Service is used to divert calls

from the original recipient to another number, and is normally set up by the subscriber

himself. It can be used by the subscriber to divert calls from the Mobile Station when the

subscriber is not available, and so to ensure that calls are not lost. A typical scenario

would be a salesperson turns off his mobile phone during a meeting with customers, but

does not with to lose potential sales leads while he is unavailable.

Call Barring: The concept of barring certain types of calls might seem to be a

supplementary disservice rather than service. However, there are times when the

subscriber is not the actual user of the Mobile Station, and as a consequence may wish to

limit its functionality, so as to limit the charges incurred. Alternatively, if the subscriber

and user are one and the same, the Call Barring may be useful to stop calls being routed

to international destinations when they are routed. routing of calls. So, GSM devised

some flexible services that enable the subscriber to conditionally bar calls .

Microcontroller Architecture 40

CHAPTER-3 MICROCONTROLLER ARCHITECTURE

3.1 Introduction

A microcontroller is a computer-on-a-chip, or a single-chip computer. Micro suggests that the

device is small, and controller tells that the device might be used to control objects, processes,

or events. Another term to describe a microcontroller is embedded controller, because the

microcontroller and its support circuits are often built into, or embedded in, the devices they

control. We can find microcontrollers in all kinds of things these days. Any device that

measures, stores, controls, calculates, or displays information is a candidate for putting a

microcontroller inside. The largest single use for microcontrollers is in automobiles—just about

every car manufactured today includes at least one microcontroller for engine control, and often

more to control additional systems in the car. In desktop computers, we can find

microcontrollers inside keyboards, modems, printers, and other peripherals. In test equipment,

microcontrollers make it easy to add features such as the ability to store measurements, to

create and store user routines, and to display messages and waveforms. Consumer products that

use microcontrollers include cameras, video recorders, compact-disk players, and ovens.A

microcontroller is similar to the microprocessor inside a personal computer. Both

microprocessors and microcontrollers contain a central processing unit, or CPU. The CPU

executes instructions that perform the basic logic, math, and data-moving functions of a

computer. To make a complete computer, a microprocessor requires memory for storing data

and programs, and input/output (I/O) interfaces for connecting external devices like keyboards

and displays. In contrast, a microcontroller is a single-chip computer because it contains

memory and I/O interfaces in addition to the CPU. Because the amount of memory and

interfaces that can fit on a single chip is limited, microcontrollers tend to be used in smaller

systems that require little more than the microcontroller and a few support components [21].

PIC microcontrollers are popular processors developed by Microchip Technology with built-

inRAM, memory, internal bus, and peripherals that can be used for many applications. PIC

originally stood for “Programmable Intelligent Computer” but is now generally regarded as a”

Peripheral Interface Controller”[22].


3.2 Components of Microcontroller

Figure 3.1 shows the component of a microcontroller. Basically, a microcontroller is a device

which integrates a number of the components of a microprocessor system onto a single chip

(IC), with the following common features: [23]

The CPU core - ranging from simple 4-bit processors to sophisticated 32/64-bit

processors

Memory (both ROM and RAM)

Some parallel digital I/O

Fig. 3.1: Main components of a microcontroller

Most microcontrollers will also combine other devices such as:

A Timer module to allow the microcontroller to perform tasks for certain time periods.

A serial I/O port to allow data to flow between the microcontroller and other devices

such as a PC or another microcontroller.

An ADC to allow the microcontroller to accept analogue input data for processing.


3.2.1 Microprocessor/CPU

A microprocessor is a programmable digital electronic component that incorporates the

functions of a central processing unit (CPU) into a single IC package. It consists of Arithmetic

Logic Unit (ALU), Program Counter (PC), Stack Pointer (SP) and registers. The main functions

of CPU are:

The ability to execute a stored set of instructions to carry out user defined tasks.

The ability to be able to access external memory chips to both read and writes data from

and to the memory.

3.2.2 Memory in a Microcontroller

3.2.2.1 Read only Memory (ROM)

ROM memory can be ROM (as in One Time Programmable memory), EPROM, or

EEPROM.[23].

This is memory that can only be read, the data being stored in the memory device

during its manufacture. Once data has been written onto ROM memory, it cannot be

easily removed and is designed for 'read only' use. ROM is referred to as being non-

volatile as it retains its contents even when the power is turned off.

Erasable Programmable Read Only Memory (EPROM). This is similar to ROM

type memory but the user can program it. The contents of the memory can be erased

from the memory by exposing the memory chip to ultraviolet radiation for a short

period of time. It can therefore be used many times over.

Electrically Erasable Programmable Read Only Memory (EEPROM). Similar to

EPROM but has part or all of the memory contents erased by the microprocessor.

3.2.2.2 Random Access Memory (RAM)

All microprocessor systems need memory that can be both read from and written to - such

memory is RAM. RAM got its name because early read-write memories were sequential,


and did not allow random access. RAM memory is used to store dynamic data (that will

change during the operation of the program).

RAM takes the form of integrated circuits that allow the stored data to be accessed in ANY

order — that is, at random and without the physical movement of the storage medium or a

physical reading head. The word "random" infers that any piece of data can be returned

quickly, and in a constant time, regardless of its actual physical location, in relation to the

previous data storage location. The key benefit of RAM is that retrieval times are short and

consistent. The disadvantages of RAM are cost and the loss of data when power is turned

off (volatile) [23] .Both ROM and EPROM memory are used to hold the program code of a

microprocessor used in an embedded system, i.e. a microprocessor used in an application

where the program code is always the same and is designed to execute every time the

system is switched on. Most development work is done using EPROM or EEPROM type

memory, ROM memory being used in the final production version (when all the program

code has been fully tested). So a typical microprocessor system will contain both ROM

(could be EPROM, EEPROM, or ROM) to store the program code, and RAM to store

dynamic data. Figure 3.2 shows the ROM of a microcontroller which is used to store the

application

Fig. 3.2 : Microcontroller ROM/RAM


program and RAM is used for data storage and stack management tasks. It is also used for

register stacks (as in the microchip PIC range of microcontrollers). Typically, the amount of

ROM type memory will vary between around 512 bytes and 4096 bytes, although some 16 bit

microcontrollers such as the Hitachi H8/3048 can have as much as 128 Kbytes of ROM type

memory. The amount of RAM memory is usually somewhat smaller, typically ranging between

1 Kbytes to 64 Kbytes

3.2.3 Input/Output Ports

I/O (input/output) is the collection of interfaces that different functional devices, of any

information processing system, use to communicate with each other. Every information transfer

is an output from one device and an input into another. For instance, on a computer, a keyboard

and mouse are considered input devices while monitors and printers are considered output

devices. Typical devices for communication between computers, such as modems and network

cards, operate as both input and output devices[23] I/O can be:

A number of digital bits formed into a number of digital inputs or outputs called a port.

These are usually eight bits wide and thus referred to as a BYTE wide port. i.e. byte

wide input port, byte wide output port.

A serial line from the microprocessor (Transmit or TX) and a serial line to the

microprocessor (Receive or RX) allowing serial data in the form of a bit stream to be

transmitted or received via a two wire interface.

Other I/O devices such as Analogue to Digital Converters (ADC) and Digital to

Analogue Converters (DAC), Timer modules, Interrupt controllers etc. (which will be

discussed later in the context of microcontrollers)

Figure 3.3 shows microcontroller ports which are used to access the outside world. The

digital I/O ports are the means by which the microcontroller interfaces to the environment.

Digital I/O tends to be grouped into byte wide ports (8 digital bits) that can be configured as

either input bits or output bits. There are some exceptions, such as the microchip PIC

16C54 with one 6-bit RA port and a byte wide RB port. The number of I/O port bits varies,

depending upon the size of the microcontroller. Some very simple 8 bit microcontroller

have as few as 4 bits of I/O, whilst those at the high end range can have as many as 33 bits

of I/O (some 16 bit microcontrollers could have around 78 bits of I/O).


Fig.3.3: Microcontroller I/O ports

3.3 Embedded Design of microcontroller

A microcontroller can be considered a self-contained system with a processor, memory and

peripherals and can be used with an embedded system. (Only the software needs be added.) The

majority of computer systems in use today are embedded in other machinery, such as

automobiles, telephones, appliances, and peripherals for computer systems. These are called

embedded systems. While some embedded systems are very sophisticated, many have minimal

requirements for memory and program length, with no operating system, and low software

complexity. Typical input and output devices include switches, relays, solenoids, LEDs, small

or custom LCD displays, radio frequency devices, and sensors for data such as temperature,

humidity, light level etc. Embedded systems usually have no keyboard, screen, disks, printers,


or other recognizable I/O devices of a personal computer, and may lack human interaction

devices of any kind.

3.3. 1 Interrupts

It is mandatory that microcontrollers provide real time response to events in the embedded

system they are controlling. When certain events occur, an interrupt system can signal the

processor to suspend processing the current instruction sequence and to begin an interrupt

service routine (ISR). The ISR will perform any processing required based on the source of the

interrupt before returning to the original instruction sequence. Possible interrupt sources are

device dependent, and often include events such as an internal timer overflow, completing an

analog to digital conversion, a logic level change on an input such as from a button being

pressed, and data received on a communication link. Where power consumption is important as

in battery operated devices, interrupts may also wake a microcontroller from a low power sleep

state where the processor is halted until required to do something by a peripheral event.

3.3.2 Programs

Microcontroller programs must fit in the available on-chip program memory, since it would be

costly to provide a system with external, expandable, memory. Compilers and assembly

language are used to turn high-level language programs into a compact machine code for

storage in the microcontroller's memory. Depending on the device, the program memory may

be permanent, read-only memory that can only be programmed at the factory, or program

memory may be field-alterable flash or erasable read-only memory.

3.3. 3 Common Features of Microcontrollers

A microcontroller is a single integrated circuit, commonly with the following features:

central processing unit - ranging from small and simple 4-bit processors to complex 32-

or 64-bit processors

discrete input and output bits, allowing control or detection of the logic state of an

individual package pin

serial input/output such as serial ports (UARTs)

other serial communications interfaces like I²C, Serial Peripheral Interface and

Controlle Area Network for system interconnect


peripherals such as timers, event counters, PWM generators, and watchdog

volatile memory (RAM) for data storage

ROM, EPROM, EEPROM or Flash memory for programand operating parameter

storage

clock generator - often an oscillator for a quartz timing crystal, resonator or RC circuit

many include analog-to-digital converters

in-circuit programming and debugging support

3.3.4 Special Features of Microcontrollers

Watchdog time: A watchdog timer provides a means of graceful recovery from a

system problem. This could be a program that goes into an endless loop, or a hardware

problem that prevents the program from operating correctly. If the program fails to

reset the watchdog at some predetermined interval, a hardware reset will be initiated.

The bug may still exist, but at least the system has away to recover. This is especially

useful for unattended systems[24].

Digital Signal Processors (DSP): Microcontrollers react to and control events - DSPs

execute repetitive math-intensive algorithms. Today many embedded applications

require both types of processors, and semiconductor manufacturers have responded by

introducing microcontrollers with on-chip DSP capability and DSPs with on-chip

microcontrollers. The most basic thing a DSP will do is a MACC (Multiply and

Accumulate). The number of data bits DSP can Multiply and Accumulate will

determine the dynamic range (and therefore the application).

Bits Fixed/Floating Dynamic Range Typical Application

8 Fixed 48 dB Telephone-quality voice

16 Fixed 96 dB Compact disk (marginal)

(room for error)

24 Fixed 144 dB Compact disk


Clock Monitor: A clock monitor can shut the microcontroller down (by holding the

microcontroller in reset) if the input clock is too slow. This can usually be turned on

or off under software control.

Resident program loader: Loads a program by Initializing program/data memory

from either serial or parallel port. Convenient for prototyping or trying out new

features, eliminates the erase/burn/program cycle typical with EPROM’s, and allows

convenient updating of a system even from an offsite location.

Monitor: A monitor is a program installed in the microcontroller which provides basic

development and debug capabilities. Typical capabilities of a microcontroller monitor

include: loading object files into system RAM, executing programs, examining and

modifying memory and registers, code disassembly, setting breakpoints, and single-

stepping through code. Some simple monitors only allow basic functions such as

memory inspection, and the most sophisticated monitors are capable of a full range of

debug functions. Monitors can either communicate with a dumb terminal or with a

host computer such as a PC. Much of the work of the monitor (such as user interface)

can be offloaded to the host PC running a program designed to work with the monitor.

This makes it possible to reduce the size and complexity of the code that must

installed in the target system.

MIL transducer: An MIL transducer is a sophisticated and expensive device that

detects the presence of mother-in-law. Sensitivity settings are possible for a full range

of stimuli such as: snarling, stomping, nasty faces, and others. Techno-Wimp

(address withheld upon request), the sole manufacturer of the MIL transducer, has

recently announced a major new version which is sensitive enough to detect less-

tangible stimuli. This breakthrough product is dubbed the MIL-WOMF transducer.

Both the original MIL and the new MIL WOMF transducers are programmable and

easy to interface to most microcontrollers[24].

3.4 Programming Environments

Microcontrollers were originally programmed only in assembly language, but various high-

level programming languages are now also in common use to target microcontrollers. These

languages are either designed specially for the purpose, or versions of general purpose


languages such as the C programming language. Compilers for general purpose languages will

typically have some restrictions as well as enhancements to better support the unique

characteristics of microcontrollers. Some microcontrollers have environments to aid developing

certain types of applications. Microcontroller vendors often make tools freely available to make

it easier to adopt their hardware. Many microcontrollers are so quirky that they effectively

require their own non-standard dialects of C, such as SDCC for the 8051, which prevent using

standard tools (such as code libraries or static analysis tools) even for code unrelated to

hardware features. Interpreters are often used to hide such low level quirks.Interpreter firmware

is also available for some microcontrollers. For example, BASIC on the early microcontrollers

Intel 8052; BASIC and FORTH on the Zilog Z8 as well as some modern devices. Typically

these interpreters support interactive programming.Simulators are available for some

microcontrollers, such as in Microchip's MPLAB environment. These allow a developer to

analyze what the behavior of the microcontroller and their program should be if they were

using the actual part. A simulator will show the internal processor state and also that of the

outputs, as well as allowing input signals to be generated. While on the one hand most

simulators will be limited from being unable to simulate much other hardware in a system, they

can exercise conditions that may otherwise be hard to reproduce at will in the physical

implementation, and can be the quickest way to debug and analyze problems.Recent

microcontrollers are often integrated with on-chip debug circuitry that when accessed by an in-

circuit emulator via JTAG, allow debugging of the firmware with a debugger.

3.5 Microcontroller Embedded Memory Technology

Since the emergence of microcontrollers, many different memory technologies have been used.

Almost all microcontrollers have at least two different kinds of memory, a non-volatile memory

for storing firmware and a read-write memory for temporary data. From the earliest

microcontrollers to today, six-transistor SRAM almost always used as the read/write working

memory, with a few more transistors per bit used in the register file. MRAM could potentially

replace it as it is 4-10 times denser which would make it more cost effective.In addition to the

SRAM, some microcontrollers also have internal EEPROM for data storage; and even ones that

don't have any (or don't have enough) are often connected to external serial EEPROM chip

(such as the BASIC Stamp) or external serial flash memory chip.this is called computers .


computers have a scientific brain or electronic brain whch is called C.P.U. A few recent

microcontrollers beginning in 2003[have "self-programmable" flash memory.

3.5.1 Data

From the earliest microcontrollers to today, six-transistor SRAM almost always used as the

read/write working memory, with a few more transistors per bit used in the register file.

MRAM could potentially replace it as it is 4-10 times denser which would make it more cost

effective.In addition to the SRAM, some microcontrollers also have internal EEPROM for data

storage; and even ones that don't have any (or don't have enough) are often connected to

external serial EEPROM chip (such as the BASIC Stamp) or external serial flash memory

chip.this is called computers. Computers have a scientific brain or electronic brain whch is

called C.P.U. A few recent microcontrollers beginning in 2003[have "self-programmable" flash

memory.

3.5.2 Firmware

The earliest microcontrollers used hard-wired or mask ROM to store firmware. Later

microcontrollers (such as the early versions of the Freescale 68HC11 and early PIC

microcontrollers) had quartz windows that allowed ultraviolet light in to erase the EPROM.

The Microchip PIC16C84, introduced in 1993, was the first microcontroller to use EEPROM to

store firmware. Also in 1993, Atmen introduced the first microcontroller using NOR Flash

memory to store firmware. PSoC microcontrollers, introduced in 2002, store firmware in

SONOS flash memory. RAM could potentially be used to store firmware.

3.6 PIC Microcontrollers

PIC is a family of Harvard architecture microcontrollers made by Microchip Technology.

Originally developed by General Instrument’s Microelectronics Division. The name PIC

initially referred to "Peripheral Interface Controller". PICs are popular with both industrial

developers and hobbyists alike due to their low cost, wide availability, large user base,

extensive collection of application notes, availability of low cost or free development tools, and

serial programming (and re-programming with flash memory) capability.

3.6.1 Core Architecture of PIC Microcontroller

The PIC architecture is distinctively minimalist. It is characterized by the following features


Separate code and data spaces (Harvard architecture)

A small number of fixed length instructions

Most instructions are single cycle execution (4 clock cycles), with single delay cycles

upon branches and skips

A single accumulator (W), the use of which (as source operand) is implied (i.e. is not

encoded in the opcode)

All RAM locations function as registers as both source and/or destination of math and

other functions.

A hardware stack for storing return addresses

A fairly small amount of addressable data space (typically 256 bytes), extended through

banking

Data space mapped CPU, port, and peripheral registers

The program counter is also mapped into the data space and writable (this is used to

implement indirect jumps.

3.6.1.1 Data Space for RAM

PICs have a set of registers that function as general purpose RAM. Special purpose control

registers for on-chip hardware resources are also mapped into the data space. The addressability

of memory varies depending on device series, and all PIC devices have some banking

mechanism to extend the addressing to additional memory. Later series of devices feature move

instructions which can cover the whole addressable space, independent of the selected bank. In

earlier devices (i.e., the baseline and mid-range cores), any register move had to be achieved

via the accumulator. To implement indirect addressing, a "file select register" (FSR) and

"indirect register" (INDF) are used: A register number is written to the FSR, after which reads

from or writes to INDF will actually be to or from the register pointed to by FSR. Later devices

extended this concept with post- and pre- increment/decrement for greater efficiency in

accessing sequentially stored data. This also allows FSR to be treated almost like a stack

pointer. External data memory is not directly addressable except in some high pin count PIC18

devices


3.6.1.2 Word Size

The word size of PICs can be a source of confusion. All PICs handle (and address) data in 8-bit

chunks, so they should be called 8-bit microcontrollers. However, the unit of addressability of

the code space is not generally the same as the data space. For example, PICs in the baseline

and mid-range families have program memory addressable in the same word size as the

instruction width, ie. 12 or 14 bits respectively. In contrast, in the PIC18 series, the program

memory is addressed in 8-bit increments (bytes), which differs from the instruction width of 16

bits. In order to be clear, the program memory capacity is usually stated in number of (single

word) instructions, rather than in bytes.

3.6.1.3 Stacks

PICs have a hardware call stack, which is used to save return addresses. The hardware stack is

not software accessible on earlier devices, but this changed with the 18 series devices.

Hardware support for a general purpose parameter stack was lacking in early series, but this

greatly improved in the 18 series, making the 18 series architecture friendlier to high level

language compilers.

3.6.1.4 Instruction Set

A PIC's instructions vary from about 35 instructions for the low-end PICs to over 80

instructions for the high-end PICs. The instruction set includes instructions to perform a variety

of operations on registers directly, the accumulator and a literal constant or the accumulator and

a register, as well as for conditional execution, and program branching. Some operations, such

as bit setting and testing, can be performed on any numbered register, but bi-operand arithmetic

operations always involve W; writing the result back to either W or the other operand register.

To load a constant, it is necessary to load it into W before it can be moved into another register.

On the older cores, all register moves needed to pass through W, but this changed on the "high

end" cores. PIC cores have skip instructions which are used for conditional execution and

branching. The skip instructions are: 'skip if bit set', and, 'skip if bit not set'. Because cores

before PIC18 had only unconditional branch instructions, conditional jumps are implemented

by a conditional skip (with the opposite condition) followed by an unconditional branch. Skips

are also of utility for conditional execution of any immediate single following instruction. The

PIC architecture has no (or very meager) hardware support for automatically saving processor


state when servicing interrupts. The 18 series improved this situation by implementing shadow

registers which save several important registers during an interrupt.

3.6.1.5 Performance

Many of these architectural decisions are directed at the maximization of top-end speed, or

more precisely of speed-to-cost ratio. The PIC architecture was among the first scalar CPU

designs, and is still among the simplest and cheapest. The Harvard architecture - in which

instructions and data come from conveniently separate sources - simplifies timing and

microcircuit design greatly, and this pays benefits in areas like clock speed, price, and power

consumption. The PIC is particularly suited to implementation of fast lookup tables in the

program space. Such lookups are O(1) and can complete via a single instruction taking two

instruction cycles. Basically any function can be modeled in this way. Such optimization is

facilitated by the relatively large program space of the PIC (e.g. 4096 x 14-bit words on the

16F690) and by the design of the instruction set, which allows for embedded constants. The

simplicity of the PIC, and its scalar nature, also serve to greatly simplify the construction of

real-time code. It is typically possible to multiply the line count of a PIC assembler listing by

the instruction cycle time to determine execution time. Execution time can be accurately

estimated by multiplying the number of instructions by two cycles; this simplifies design of

real-time code. Similarly, interrupt latency is constant at three instruction cycles. External

interrupts have to be synchronized with the four clock instruction cycle, otherwise there can be

a one instruction cycle jitter. Internal interrupts are synchronized. .The constant interrupt

latency allows PICs to achieve interrupt driven low jitter timing sequences. An example of this

is a video sync pulse generator. This is no longer true in the newest PIC models, because they

have a synchronous interrupt latency of three or four cycles. Basically any function can be

modeled in this way. Such optimization is facilitated by the relatively large program space of

the PIC (e.g. 4096 x 14-bit words on the 16F690) and by the design of the instruction set,

which allows for embedded constants.


3.7 Block Diagram of Study BasePIC18F2550 Microcontroller The block diagram of PIC18F2550 microcontroller is shown in fig .3.4 [25]

Fig: 3.4 Block Diagram of PIC18F2550 Microcontroller

Note 1: RE3 is multiplexed with MCLR and is only available when the MCLR Resets are disabled.

2: OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.


3.8 Pin Diagram of Study Based Microcontroller (PIC18F2550)

Fig.3.5: Pin Diagram of the PIC18F2550 Microcontroller

PIC

18F

2550


3. 9 Pin Out I/O Description of PICF18 2550 Microcontroller

Table 3.1 Pin Functions of PIC18F2550 Microcontroller


3.9 Pin Out I/O Description of PICF18 2550 Microcontroller

Table 3.1 Pin Functions of PIC18F2550 Microcontroller Continue


3.10 Memory Organization

There are three types of memory in PIC18F2550 enhanced microcontroller device:

• Program Memory

• Data RAM

• Data EEPROM

As Harvard architecture devices, the data and program memories use separate busses; this

allows for concurrent access of the two memory spaces. The data EEPROM, for practical

purposes, can be regarded as a peripheral device, since it is addressed and accessed [22] .

3.10.1 Program Memory

The program memory map for PIC18F2550 is shown in fig 3.6

Fig. 3.6: Program Memory Map and Stack for PIC18F2550 Device


PIC18F2550 microcontrollers implement a 21-bit program counter which is capable of

addressing a 2-Mbyte program memory space. Accessing a location between the upper

boundary of the physically implemented memory and the 2-Mbyte address will return all ‘0’s (a

NOP instruction).. The PIC18F2550 has 32 Kbytes of Flash memory and can store up to 16,384

single-word instructions.PIC18 F2550 devices have two interrupt vectors. The Reset vector

address is at 0000h and the interrupt vector addresses are at 0008h and 0018h.

3.10. 2 Data Memory

The data memory in PIC18F2550 device is implemented as static RAM. Each register in the

data memory has a12-bit address, allowing up to 4096 bytes of data memory.

Fig. 3.7: Data Memory Map for PIC18F2550 Device


The memory space is divided into as many as16 banks that contain 256 bytes

each.PIC18F2550device implement eight complete banks, for a total of 2048 bytes. Figure

3.7shows the data memory organization for the device. The data memory contains Special

Function Registers (SFRs) and General Purpose Registers (GPRs). The SFR is used for control

and status of the controller and peripheral functions while GPRs are used for data storage and

scratchpad operations in the user’s application. Any read of an unimplemented location will

read as ‘0’s.The instruction set and architecture allow operations across all banks. The entire

data memory may be accessed by Direct, Indirect or Indexed Addressing modes[25].

3.10.3 Data EEPROM Memory

The data EEPROM is a nonvolatile memory array separate from the data RAM and program

memory that is used for long-term storage of program data. It is not directly mapped in either

the register file or program memory space, but is indirectly addressed through the Special

Function Registers (SFRs). The EEPROM is readable and writable during normal operation

over the entire VDD range. Four SFRs are used to read and write to the data EPROM as well as

the program memory. They are:

• EECON1

• EECON2

• EEDATA

• EEADR

The data EEPROM allows byte read and writes. When interfacing to the data memory block,

EEDATA holds the 8-bit data for read/write and the EEADR register holds the address of the

EEPROM location being accessed. The EEPROM data memory is rated for high erase/write

cycle endurance. A byte write automatically erases the location and writes the new data (erase-

before-write).The write time is controlled by an on-chip timer; it will vary with voltage and

temperature as well as from chip to chip[25].

3.10.3.1 EECON1 and EECON2 Registers.

Access to the data EEPROM is controlled by two registers: EECON1 and EECON2. These are

the same registers which control access to the program memory and are used in a similar

manner for the data EEPROM. The EECON1 register is the control register for data and


program memory access. Control bit, EEPGD, determines if the access will be to program or

data EEPROM memory. When clear, operations will access the data EEPROM memory. When

set, program memory is accessed. The EECON2 register is not a physical register. It is used

exclusively in the memory write and erase sequences. Reading EECON2 will read all ‘0’s.

Fig. 3.8 : EECON1 Data EEPROM Control Register 1

Digital Energy Meter 64

CHAPTER-4 DIGITAL ENERGY METER

4.1 Introduction

This application note describes a high-accuracy, low-cost power meter based on the ADE7756.

The design is for use in the North American 3-wire/single-phase application. This meter may

also be used in a single-phase, 2-wire distribution system with a minimal amount of changes.

The reference design is comprised of the ADE7756, a microcontroller, LCD display, serial

interface, and power supply. The ADE7756 is designed to interface to a microcontroller through

a serial interface (SPI). The SPI port allows the user to calibrate various components of the

meter, including gain, offset, and phase errors. The purpose of the microcontroller is to send

display data to the LCD and control the various functions of the meter. An EPROM is used to

store various calibration parameters of the meter and store the meter’s data during a power-

down. The entire meter is calibrated through an external calibration routine by a PC through an

external SPI interface. Application is limited to the ANSI standard; the accuracies achieved are

well within the accuracy requirements of the IEC1036 standards for a Class 1 meter. For

reference,, comparing the IEC1036 and ANSI C12.16 standards. This section explains the key

IEC1036 specifications in terms of their ANSI equivalents. This design greatly exceeds the

definition for many of the accuracy requirements, e.g., accuracy at unity power factor and at low

(PF = ±0.5) power factor. In addition, the dynamic range performance of the meter has been

extended to 500.The ANSI standard defines the maximum current of a Class 100 watt-hour

meter as100 amps with a reference current (IREF) of 15 amps.. The current range (dynamic

range) for accuracy is specified in terms of IREF.The ADE7756 is comprised of two ADCs, a

reference circuit, and all the signal processing necessary for the calculation of real (active)

power. Circuitry is provided tonal out various system errors including gain, phase, and offset

errors. Additional circuitry provides waveform sampling, programmable interrupts, and power

line monitoring. All registers of the ADE7756 are available through the SPI port. The data sheet

provides detailed information on the functionality of the ADE7756 and will be referenced

several times in this application note. This application note should be used in conjunction with

the ADE7756 [26].


4.2 Circuit Diagram and Operation of Digital Energy Meter

The schematic circuit diagram of digital energy meter shown in figure 4.1. It is mainly composed

of energy measuring chip, microcontroller. and LCD display. The main parameters of energy

measuring chip are programmable gain amplifiers, AD converters, high pass filter, low pass

filter, multiplier, calibration resister, wave form resister and active energy \ resister etc. The

working principle of the circuit such as when the load is connected with the meter only current

flows through 0.1ohms resistance because input impedance of the programmable gain is infinite

and no current flows from V+ terminal to V1- terminal. The major portion of voltage will be

dropped across the load and remaining across 0.1Ώ ohms resistance. The voltage across 0.1Ώ

ohms resistance

Fig. 4.1: Circuit Diagram of Digital Energy Meter

is directly proportional to current since the value of the resistance is fixed that will be acted as a

voltage source for the programmable gain amplifier V1+terminal. The V1+ terminal of


programmable gain amplifier circuit senses minimum voltage across 9.5k ohms resistance and

consequently V1- terminal of the device senses 0V across the 1k ohms resistance since voltage

source is zero. The output of this amplifier is Ao(V1+ -V1_) volt where Ao is the gain of the

amplifier. Again according to voltage divided rules 0.9V voltage will be obtained across 1k ohms

resistance with respect to 2.2M ohms resistance from 220V supply. The voltage across 1k ohms

resistance will be acted as a voltage source for programmable gain amplifier V2+ terminal. The

V2+ and V2_ are the terminals of programmable gain amplifier-2 circuit which sense 0.9V volt

across 9.5k ohms resistance and 0V across 1k ohms resistance (Due to source voltage is zero)

respectively. The output of this amplifier Ao(V2+ -V2_) volt. In fact the energy measuring chip

of digital energy meter produces serial digital data output in energy mode from analog signal by

the sequential action of its consisting parameters that is interfaced with controlling

microcontroller. Later microcontroller data reads from energy measuring chip, accumulates,

calculate, store and display energy data on LCD display. In this circuit two 9.5k ohms variable

resistance are used for calibrating the meter. In fact the microcontroller interfaces with ADE7756

chip via CS, SCLK, DOUT, and DIN terminals. The CS means chip select part of the 4-wire

serial interface. This active low logic input allows the ADE7756 to share the serial bus with

several other devices. The SCLK means serial clock input for the synchronous serial interface.

All serial data transfers are synchronized to this clock.. The SCLK has a Schmitt-trigger input for

use with a clock source that has a slow edge transition time, e.g., opto-isolator outputs. The

DOUT means data output for the serial interface. Data is shifted out at this pin on the rising edge

of SCLK. This logic output is normally in a high impedance state unless it is driving data onto

the serial data bus. The DIN means data input for the serial interface. Data is shifted in at this

pin on the falling edge of SCLK [27]. It may be noted that the high pass and low pass filter are

used for removing the unwanted signal.

4.3 General Description of Energy Measuring Chip ADE7756

This is the energy measuring chip of digital energy meter and the working mechanism of the chip

such as Programmable gain amplifier-1 senses voltage is proportional to current in analog mode

and fed to (ADC -1) converter. Analog to digital converter (ADC-1) converts the analog signal

into digital signal. An active power gain resister and multiplier-1 are available to adjust the gain

of the output of analog to digital (ADC-1) converter. High pass filter (HPF1) is available to


cancel an offset error affect. An offset is a dc signal that generate by thermal agitation and either

positively or negatively affect the main quantity. The result of high pass filter is fed to

multiplier-2. The result of multiplier-2 feds low pass filters -2. The low pass filter-2 only

extracts average (active) power. The output of low pass filter -2 and active power offset resister

fed to summing operational amplifier. Active power offset resister is available to cancel the

offset error affect. For measuring the energy accurately it is need to remove offset signal. The

output of operational summing amplifier is multiplied with power factor. [Multiplied by cosǾ

that angle calibrate by phase calibration resister]This active power is fed to energy calculation

block. Energy is calculated as the summation of the product of active power and the sampling

time which is 1.4 us that is loaded into 40 bit resister up to 10 second. This energy is interfaced

with controlling microcontroller.

Fig .4.2: Functional Block Diagram of the System.

The ADE7756 also provides a pulse output (CF) with a frequency that is proportional to the

active power [26]. In addition to real power information, the ADE7756 also provides system


calibration features, i.e., channel offset correction, phase calibration, and power calibration. The

part also incorporates a detection circuit for short duration low voltage variations or sags the

voltage threshold level and the duration (in number of half line cycles) of the variation is user

programmable. An open drain logic output (SAG) goes active low when a sag event occurs .A

zero crossing output (ZX) produces an output that is synchronized to the zero crossing point of

the line voltage. This output can be used to extract timing or frequency information from the line.

The signal is also used internally to the chip in the calibration mode. This permits faster and

more accurate calibration of the real power calculation.

4.4 Analog Input

The ADE7756 has two differential voltage input channels. The maximum differential input

voltage for each input pair (V1P/V1N and V2P/V2N) is ±1 V. In addition,

Fig. 4.3: Analog Gain Resisters

the maximum signal level on each analog input (V1P, V1N, V2P, and V2N) is also ±1 V with

respect to AGND. Each analog input channel has a PC Program Counter, PGA (Programmable

Gain Amplifier) with possible gain selections of 1, 2, 4, 8, and 16.The gain selections are made

by writing to the Gain register Figure 4.3. Bits 0 to 2 select the gain for the PGA in Channel 1


and the gain selection for the PGA in Channel 2 is made via bits 5 to 7. Figure 4.4 shows how a

gain selection for Channel 1 is made using the Gain register[26] .Channel 1 also has a full-scale

input range selection for the ADC. The ADC analog input range selection is also made using the

Gain register—shows Figure 4.4. As mentioned previously, the maximum differential input

voltage is±1 V However, by using Bits 3 and 4 in the Gain register, the maximum ADC input

voltage can be set to 1 V, 0.5 V, or 0.25 V. This is achieved by adjusting the ADC reference

Table I

Fig. 4.4: PGA in Channel -1

summarizes the maximum differential input signal level on Channel 1 for the various ADC range

and gain selections. It is also possible to adjust offset errors on Channel 1 and Channel2 by

writing to the Offset Correction Registers (CH1OS andCH2OS respectively). These registers

allow channel offsets in the range ±20 mV to ±60 mV (depending on the gain setting) to be

removed. Note that it is not necessary to perform an offset correction in Energy measurement

application if HPF1 in Channel 1is switched on. Figure 4.5 shows the effect of offsets on the real

power calculation.. Since this dc component is extracted by LPF2 to generate the Active (Real)

Power information, the offsets will have contributed an error to the Active Power calculation

This problem is easily avoided by enabling HPF1 in Channel 1. By removing the offset from at

least one channel, no error component can be generated at dc by the multiplication. Error terms


at Cos (ωt) are removed by LPF2 and by integration of the Active Power signal in the Active

Energy register (AENERGY[39:0]).

Fig. 4.5: Effects of Channel Offsets on the Real Power Calculation 4.5 Active Power Calculation

Electrical power is defined as the rate of energy flow from source to load. It is given by the

product of the voltage and current waveforms. The resulting waveform is called the

instantaneous power signal and it is equal to the rate of energy flow at every instant of time. The

unit of power is the watt or joules/sec. Equation (3) gives an expression for the instantaneous

power signal in an ac system. The unit of power is the watt or joules/sec.

v(t)= 2 Vsin( t ) (1)

i(t) = 2 Vcos( t ) (2) Where V = rms voltage, I = rms current. p(t)=v(t)×i(t) (3) p(t)= VI- VIcos(2 t )


P=nT

1nT

dttp0

)( =VI (4)

Where T is the line cycle period and P is referred to as the Active or Real power. One note that

the active power is equal to the dc component of the instantaneous power signal p(t) in Equation

3 , i.e., VI. This is the relationship used to calculate active power in the ADE7756.The

instantaneous power signal p (t) is generated by multiplying the current and voltage signals. The

dc componentof the instantaneous power signal is then extracted by LPF2 (Low-Pass Filter) to

obtain the active power information. This process is graphically illustrated in Figure 4.6

Fig. 4.6: Active Power Calculations

Since LPF2 does not have an ideal” brick wall” frequency response may be seen Figure 4.7—the

Active Power signal will have some ripple due to the instantaneous power signal. This ripple is

sinusoidal and has a frequency equal to twice the line frequency. Since the ripple is sinusoidal

immature it will be removed when the Active Power signal is integrated to calculate Energy[26].


Fig. 4.7: Frequency Response of LPF . Active Power Signal Processing Shown in Figure 4.8 is the maximum code (Hexadecimal)

output range for the Active Power signal (LPF2). Note that the output range changes, depending

on the contents of the Active Power Gain register Channel 1 ADC section. The minimum output

range is given when the Active Power Gain register contents are equal to 800h, and the

maximum range is given by writing 7FFh to the Active Power Gain register. This can be used to

calibrate the Active Power (or Energy) calculation in the ADE7756


Fig. 4.8: Active Power Signal Processing

Fig. 4.9: Active Power Calculation Output Range 4.6 Energy Calculation As stated earlier, power is defined as the rate of energy flow. This relationship can be expressed

mathematically as Equation 5.

P=dt

dE (5)

Where


P = Power, and E = Energy

Conversely, Energy is given as the integral of Power.

.

E= pdt (6)

The ADE7756 achieves the integration of the Active Power signally continuously accumulating

the Active Power signal in the 40-bitActive Energy register (AENERGY [39:0]). This discrete

time accumulation or summation is equivalent to integration in continuous time. Equation 7

expresses the relationship

E= pdt =Limit { TnTpn

0)( } (7)

T 0 Where n is the discrete time sample number And T is the sample period.

Fig.4.10: Energy Calculations

The discrete time sample period (T) for the accumulation registering the ADE7756 is 1.1 μs

(4/CLKIN). As well as calculating the Energy, this integration removes any sinusoidal

components that may be in the Active Power signal. Figure 4.10 shows a graphical

representation of this discrete time integration or accumulation. The Active Power signal in the

Waveform register is continuously added to the Active Energy register. This addition is a signed

addition; therefore negative energy will be subtracted from the Active Energy contents[26].


4.7 Energy Calibration

By using the on-chip zero-crossing detection on Channel 2 the energy calibration can be greatly

simplified and the time required to calibrate the meter can be significantly reduced. To use the

zero-cross detection the ADE7756 is placed in calibration modeby setting Bit 7 (CMODE) in the

Mode register. In Calibration Mode the ADE7756 accumulates the Active Power signal in the

Active Energy register for an integral number of half cycles, as shown in Figure 4.11.

Fig. 4.11: Energy Calculations in Calibration Mode

The number of half-line cycles is specified in the SAGCYC register. The ADE7756 can

accumulate Active Power for up to 255 half-cycles. Because the Active Power is integrated on an

integral number of line cycles, the sinusoidal component is reduced to zero. This eliminates any

ripple in the energy calculation. Energy is calculated more accurately and in a shorter time

because integration period can be shortened. At the end of an energy calibration cycle the SAG

flag in the Interrupt Status register is set; this will cause the SAG output to go active low. If the

SAG enable bit in the Interrupt Enable register is enabled, the IRQ output will also go active low.

Thus the IRQ line can be used to signal the end of a calibration also. Another calibration cycle

will start as long as the CMODE bit in the Mode register is set. Note that the result of the first


calibration is invalid and must be ignored. The result of all subsequent calibration cycles is

correct[23].From Equations (5 )and other relevant equation,

E(t)= nT

VIdt0

{ Hzfl

VI

9.8/21}

nT

dtt0

)2cos( (8)

Where n is an integer and T is the line cycle period. Since the sinusoidal component is integrated over an integer number of line cycles, its value is always zero. Therefore:

E (t) = nT

VIdt0

(9)

E (t) =VInT (10)

4.8 Analog to Digital Conversion The analog-to-digital conversion in the ADE7756is carried out using two second-order sigma-

delta ADCs. The block diagram in Figure 4.12 shows a first-order (for simplicity) sigma-delta

ADC. . The converter is made up of two parts, first the sigma delta modulator and seconds the

digital low pass filter. A sigma-delta modulator converts the input signal into a continuous serial

streamof1sand 0s at a rate determined by the sampling clock.

Fig.4.12: First Order Sigma Delta ADC

In theADE7756 the sampling clock is equaltoCLKIN/4. The 1-bit DAC in the feedback loop is

driven by the serial. Sampling interval, the data from the 1-bit ADC is virtually meaningless.


Only when a large number of samples are averaged, will a meaningful result be obtained.This

averaging is carried out in the second part of the ADC, the digital low-pass filter. By averaging

large number of bits from the modulator the low-pass filter can produce 20-bit data words that

are proportional to the Input signal level .The sigma-delta converter uses two techniques to

achieve high-resolution from what is essentially a 1-bit conversion technique. The first is over

sampling By over sampling we mean that the signal is sampled at a rate (frequency) that is many

times higher than the bandwidth of interest..

Fig. 4.13: Noise Reduction Due to over sampling and Noise Shaping in the Analog Modulator

For example, the sampling rate in the ADE7756 is CLKIN/4 (894 kHz) and the band of interest

is 40 Hz to 2 kHz. Over sampling has the effect of spreading the quantization noise (noise due to

sampling) over a wider bandwidth. With the noise spread more thinly over a wider bandwidth,


the quantization noise in the band of interest is lowered—shows Figure 4.15 However over

sampling alone is not an efficient enough method to improve the signal to noise ratio (SNR) in

the band of interest. For example, an over sampling ratio of 4 is required just to increase the SNR

by only 6 dB(1 bit). To keep the over sampling ratio at a reasonable level, it is possible to shape

the quantization noise so that the majority of the noise lies at the higher frequencies. This is what

happens in the sigma-delta modulator, the noise is shaped by the integrator which has a high-

pass-type response for the quantization noise. The result is that most of the noise is at the higher

frequencies where it can be removed by the digital low-pass filter. This noise shaping is also

shown in Figure 4.13 [27].

4.9 Calibrating the Energy Meter

4.9.1 Calculating the Average Active Power

When calibrating the ADE7756, the first step is to calibrate the frequency on CF to some

required meter constant, e.g.,3200 imp/kW H .In order to determine the output frequency on CF,

the average value of the Active Power signal (output of LPF2) must first be determined. One

convenient way to do this is to use the calibration mode. When the CMODE (Bit 7) bit in the

Mode register is set to a Logic 1, energy is accumulated over an integer number of half-line

cycles. Since the line frequency is fixed at, assume, 50Hz, and the number of half-cycles of

integration is specified, the total integration time is given as:[26]

Hz502

1Number of half cycle

For 255 half-cycles this would give a total integration time of2.125 seconds. This would mean the energy register is updated2.125/1.1175 μs (4/CLKIN) times. The average output value of LPF2 is given as: Or equivalently, in terms of contents of various ADE7756AN registers and CLKIN and line frequencies (fl):

Average word (LPF2) =CLKINSAGCYC

flAENERGY

]0:7[

8]0:39[

Where fl is the line frequency


4.9.2 Calibrating the Frequency at CF

Once the average Active Power signal is calculated it can be used to determine the frequency at

CF before calibration . When the frequency before calibration is known, the Calibration

Frequency Divider register (CFDIV) and the Active Power Gain register (APGAIN) can be

adjusted to produce the required frequency on CF. In this example, a meter constant of 3200

imp/kWh is chosen as an appropriate constant. This means that under a steady load of 1 kW, the

output frequency on CF would be,

Frequency (CF) = HzKWhimp

8888.03600

3200

sec60min60

/3200

80

CHAPTER-5

DESIGN AND DEVELOPMENT OF MICROCONTROLLER BASED ENERGY METER SYSTEM

5.1 Introduction

The goal of the thesis is generation, transmission and reception of digital energy meter reading from

consumer residence to organization using SMS technology under coverage by GSM network. For this

purpose initially design the circuit, write appropriate program, install program into microcontroller and

assemble all the equipments have been done in a test board for easier testing and modifying. When it is

worked successfully then transfers to the main circuit board. It may be noted that write program in Basic

and Assemble programming language and PIC BASIC Pro software uses as compiler. The program code

saves as text file and run through compiler. The compiler reads the text file and generates an equivalent

machine code instruction list of the program. The list of instruction is a hexadecimal file that represents

PICBASIC Pro Program. The program is uploaded into PIC18F2550 microcontroller using programmer

and EPIC Win software.

5.2 Block Diagram and Descriptions of Each Block

The overall block diagram of the system is shown in figure:5 1 The system mainly consists of energy

measuring chip, microcontroller, GSM- module including SIM and liquid crystal display. The functions

of each block are gradually given below.

Energy Measuring Chip: The energy measuring chip of digital energy meter consists of

comparators circuit, analog to digital converter (ADCs), low pass filter, high pass filter,

multiplier, phase adjuster, wave and real power resister. The comparators circuit senses the

voltage and current indirectly in analog signal mode and converts the analog signal into

digital signal using the analog to digital converters. The digital value of voltage, current and

power factor are multiplied by multiplier circuit and produce the real power. This real power

holds by the wave register for few seconds and later provide to the real power register in

binary form. It may be noted that high pass filter and low pass filter are used for filtering the

unwanted frequency.

Microcontroller: The microcontroller is a small computer that composed of program

memory, data memory, data EEPROM, program counter(PC), instruction register(IR), data

bus, address bus, oscillators, timers, ALU and I/O ports etc. In this system program is

loaded into program memory and data memory is used for keeping the data on temporary

basic. The data memory controls the peripheral functions also. As per program the

81

arithmetic logic unit complete arithmetic and logical operation which produces desire data

reading. Later it is stored into the data EEPROM memory continuously. The oscillator circuit

generate clock and timer circuit controls Read/Write data time. It may be noted program

counter store next instruction for execution, instruction register store instruction, data bus

carry the data and address bus carry the address.

GSM Module and SIM: GSM module is a wireless module that works with GSM network.

GSM module internally interfaces with SIM card and it requires SIM for operating purpose.

In this system GSM module reads the data reading code from microcontroller, produces

short message on the basic of data reading code and send SMS through radio waves.

a

.

5.3 Work Flow Diagram of the System The work flow diagram of the system is shown in figure 5.2

GSM MODULE AND SIM

MICROCONTROLLER

ORGANIZATION SERVER

LCD

DISPLAY

ENERGY

MEASURING CHIP

TO LOAD

SMS

MOBILE COMMUNICATION

SYSTEMS

LCD Display: Liquid crystal display is an optically modulated electronic device and made up of any

number of light source or monochrome pixel filled with liquid crystals . It receives data reading from

microcontroller interfacing with four data cables in binary form and converts this data reading into

decimal form. It is used for displaying the meter reading.

Mobile Communication Systems: In this system digital energy meter reading reaches from consumer

residence to organization server in SMS mode via mobile communication systems that means GSM

module-BTS-BSC-MSC-GMSC-MSC-BSC-BTS- Organization

81

Fig. 5.1: Block Diagram of the System

82

Research and Study

Planning for circuit design and for writing of appropriate program for microcontroller

Write/ compile and install program into

microcontroller using Basic Language/

PICBASIC Pro, EPIC Programmer board and software.

Assemble circuit with microcontroller, GSM module, SIM, digital energy meter, LCD-display & devices controlled in a test board

Test Modify, programming , trouble shooting of hardware Parts .

IS PROGRAM, HARDWARE PARTS OK

Circuit with program finalized and circuit completed by assembling in appropriate PCB.

Yes

Test

IS CONNECTION OK

Job completed

Check PCB Connection & etc

No

Yes

No

Fig. 5.2: Work Flow Chart

5.3 Work Flow Chart The work flow diagram of the system is shown in figure 5.2

83

5.4 Program Flow Chart of the System

The program flow chart of the system is shown in figure 5.3

START

DEFINE LCD IN/OUT PIN

DEFINE PHONE NUMBER

READ EEPROM

SETTING DATE

COUNTING DATE

IS SETTING DATE

=COUNTING DATE

READ DIGITAL ENERGY METER READING

CALCULATE READING IN KWH FORM

DISPLAY READING ON LCD EACH 10 SECOND

WRITE EEPROM

No

Yes

ENABLE GSM MODULE

SEND AND DELETE MESSAGE

Fig. 5.3: Program Flow Chart of the System

CONNECT GSM

MAIN PROGRAM

IS POWER AVAILABL

WRITE DATA EEPROM

GOTO MAIN PROGRAM

YES No

84

5.5 Interfacing Circuit When one circuit or module interfaces with another circuit or module by some components then it is

called interfacing circuit.

5.5.1 Interfacing Circuits between Microcontroller and GSM Module

The figure 5.4(a), 5.4(b) 5.4(c) and represents the interfacing circuit between MCU and GSM module that are used for different activities.

The 5.4(b) interfacing circuit is used for maintaining the time continuation that means GSM

Fig. 5.4 (a): Interfacing Circuit between GSM Module and Microcontroller

The 5.4(a) interfacing circuit is used for providing the digital energy meter reading from microcontroller to the GSM module at the first day of the each month. By this circuit MCU always send request signal to the GSM module for knowing time from GSM network. In this circuit Zener diode is used for providing the constant voltage supply to the GSM Module from MCU. When the value of the voltage is going to be above 3.9V in that case excess voltage will be drop across the resistor 220R and maintain to provide the constant voltage supply to the GSM module. The GSM Module takes time from GSM network and provide this time to the microcontroller. By this circuit GSM module gives reply about time to microcontroller corresponding each request signal each second later. In this circuit two transistors are used for switching purpose. The working mechanism of this circuit such as when active low voltage signal is applied to the first transistor base in that case transistor will go to cut off reason and output of the first transistor will be active high. This high voltage signal will be applied to the base of the second transistor. In that case the second transistor will go to the saturation reason and output of it will be low and that is applied to the MCU.

The 5.4(a) interfacing circuit is used for providing the digital energy meter reading from microcontroller to the GSM module at the first day of the each month. By this circuit MCU always send request signal to the GSM module for knowing time from GSM network. In this circuit Zener diode is used for providing the constant voltage supply to the GSM Module from MCU. When the value of the voltage is going to be above 3.9V in that case excess voltage will be drop across the resistor 220R and maintain to provide the constant voltage supply to the GSM module.

85

Whereas when the high voltage signal is applied to the first transistor base in that case the transistor will

go to saturation reason and output will be low. This low voltage signal is applied to the base of the

second transistor and in that case output will be high that is applied to the microcontroller terminal.

Fig. 5.4 (b): Interfacing Circuit between GSM Module and Microcontroller

Fig.5.4(c): Interfacing Circuit between GSM Module and Microcontroller

86

5.5.2 Interfacing Circuit between GSM Module and GSM Network

Fig. 5.5: Interfacing Circuit between GSM Module and GSM Network.

This is the interfacing between GSM networks and GSM module. By this circuit GSM module

takes information about network .The first blinking of LED indicates that the network is not

available and whereas the slow blinking of LED indicate that the network is available.

5.5.3 Interfacing Circuit Between Microcontroller and Energy Measuring Chip

This is the interfacing circuit between microcontroller and energy measuring chip .The energy measuring

chip terminal 17(CS), 18(Dout), 19(Sclk) and 20(Din) directly interfaced with microcontroller pin

14(VUSB), 13(RC2/CCP1), 12(RC1/TIOS1) and 11(RCO/TIOSO). The four line is made communication

between EMC and MCU. The CS means chip select pin part of the 4-wire serial interface. This active low

logic input allows the ADE7756 to share the serial bus with several other devices. The SCLK means

serial clock input for the synchronous serial interface. All serial data transfers are synchronized to this

clock. The SCLK has a Schmitt-trigger input for use with a clock source that has a slow edge transition

time, e.g., opto-isolator outputs. The DOUT means data output for the serial interface. Data is shifted out

at this pin on the rising edge of SCLK. The DIN means data input for the serial interface. Data is shifted

in at this pin on the falling edge of SCLK

87

5.5.4 Interfacing Circuit Between Microcontroller and Liquid Crystal Display

The figure 5.7 represents the interfacing circuit between microcontroller and Liquid Crystal

Display (LCD). The terminal of LCD D4, D5, D6, and D7 directly interfaced with.

microcontroller terminal 21(RBO/SDA), 22(RB1/SCL), 23(RB2/VMO) and 24(RB3/VPO).

EMC

Fig.5.6: Interfacing circuit Between MCU and EMC

Fig.5.7: Interfacing Circuit Between MCU and LCD

88

The enable and reset terminal E and RS of LCD display directly interfaced with microcontroller

terminal 25(RB4/KB10) and 26(RB5/PGM) respectively. This circuit is used for providing the

digital energy meter reading from MCU to LCD display.

5.5.5 Interfacing Circuit Between GSM Module and SIM

The figure 5.8 represents the interfacing circuit between module and SIM. The module power

pin (SIM_VDD) directly connected with SIM power pin VDD. The module reset pin RST_SIM

connected with SIM pin SIM_RST through 22R. Either used itself (reset signal supplied from the

interface device) or in combination with an internal reset control circuit (optional use by the card) The

module clock pin SIM_CLK connected with SIM clock pin SIM_CLK via 22R. CLOCK: Clocking or

timing signal (optional use by the card) provide from module. Again the module data pin (SIM_DATA)

interfaced with SIM pin SIM _DATA via 22R . GND: Ground (reference voltage). DATA: Input or

Output for serial data to the integrated circuit inside the card.

5.6 Power Supply Unit

Power supply is a reference to a source of electrical power. A device or system that supplies electrical or

other types of energy to an output load or group of loads is called a power supply unit or PSU. The term is

most commonly applied to electrical energy supplies, less often to mechanical ones, and rarely to others

Fig. 5.8 : Interfacing Circuit Between GSM Module and SIM

89

5.6 .1 Switched-Mode Power Supply

A switched-mode power supply (SMPS) works on a different principle. AC mains input is

directly rectified without the use of a transformer, to obtain a DC voltage. This voltage is then

sliced into small pieces by a high-speed electronic switch. The size of these slices grows larger

as power output requirements increase. The input power slicing occurs at a very high speed

(typically 10 kHz — 1 MHz). High frequency and high voltages in this first stage permit much

smaller step down transformers than are in a linear power supply. After the transformer

secondary, the AC is again rectified to DC. To keep output voltage constant, the power supplies

needs a sophisticated feedback controller to monitor current draw by the load[28].

5.6.2 Study Base Power Supply Unit

The figure 5.9 represents the study base power supply unit. This circuit produces three types of voltage

such as 12V DC , 5VDC and3.93V DC. This circuit is composed of fuse , switch, step down

transformer, full wave rectifier, capacitors, regulated Ices, resistors and LED etc. The operating

mechanism of the system such as when step down transformer gets 220V AC supply in primary side, it

secondary side corresponding produces 12VAC supply .

Fig.5.9: Power Supply Unit

The output of transformer is fed to full wave rectifier and full wave rectifier converts 12v ac supply into 12v pulsating dc supply. The 2200uF director capacitor is used for smoothing the wave, remove the re pole and produces purely DC supply. and bypass capacitors are used for passing the high pass signal to the ground. The voltage regulating IC L7805 produces 5v dc supply from 12vdc that are used for microcontroller, LCD display as biasing voltage and consequently LM317 produces 3.9v dc supply from 12v dc supply that is used for GSM module

90

5.7 Feature of Study Based Microcontroller ( PIC18F2550 )

The feature of PIC18F2550 microcontroller is shown in table 5.1.

Table. 5.1 Feature of Study Base Microcontroller

Features PIC18F2550

Operating Frequency DC – 48 MHz

Program Memory (Bytes)

32768

Program Memory (Instructions)

16384

Data Memory (Bytes)

2048

Data EEPROM Memory (Bytes)

256

Interrupt Sources 19 I/O Ports Ports A, B, C, (E) Timers 4 Capture/Compare/PWM Modules 2 Enhanced Capture/ Compare/PWM Modules

0

Serial Communications

MSSP, Enhanced USART

pin SOIC Universal Serial Bus (USB) 1 Streaming Parallel Port (SPP) No 10-Bit Analog-to-Digital Module 10 Input Channels Comparators 2 Resets (and Delays)

POR, BOR, RESET Instruction,

Stack Full, Stack Underflow (PWRT, OST),

MCLR (optional), WDT

Programmable Low-Voltage Detect

Yes

Programmable Brown-out Reset Yes

Packages

28-pin PDIP 28-pin SOIC

Design & Development 91

5.8 GSM Module

GSM Modules are similar to GSM Modems, but there's one difference: A GSM Modem is an

external equipment, whereas the GSM Module is a module that can be included within an

equipment. It is an embedded piece of hardware. A GSM module is a wireless module that works

with GSM networks. A wireless module behaves like a Hayes compatible dial-up modem. The

main difference between a standard Hayes modem and a GSM module is that a Hayes modem

sends and receives data through a fixed telephone line while a GSM module sends and receives

data through radio waves. Like a GSM mobile phone, a GSM module requires a SIM card from a

wireless carrier in order to operate. GSM modules and normal Hayes modems support a common

set of AT commands. A GSM module can be used just like a Hayes compatible modem. GSM

modules support an extended set of AT commands. These extended AT commands are defined in

the GSM standards. With the extended AT commands, we can do things like:

Read, write and delete SMS messages.

Send SMS messages.

Monitor the signal strength.

Monitor the charging status and charge level of the battery.

Read, write and search phone book entries.

The number of SMS messages that can be processed by a GSM module is pretty low, approx six

messages per minute. GPRS Modules are similar to modems, but there's one difference: A GRPS

Modem is external equipment, whereas the GPRS Module is a module that can be integrated

within equipment. It is an embedded piece of hardware A GPRS module is a GSM module with

additional support for GPRS technology for data transmission. GPRS means: General Packet

Radio Service'. It is based on a packet-switched technology, as an extension to GSM (note that

GSM is a circuit-switched). An advantage of GPRS over GSM is that GPRS has transmission

speed. a much higher data GPRS can be used as the bearer of SMS. If SMS over GPRS is used,

an SMS transmission speed of about 30 SMS messages per minute may be achieved. This is

much faster than SMS over GSM. A GPRS modem is required to send and receive SMS via

GPRS. Some wireless carriers do not support the sending and receiving of SMS via GPRS. In

this study SIM 300 module is used.


5.8.1 Pin Diagram of Study Base GSM Module (SIM300CZ)

The pin diagram of study base module is shown in figure 5.10

Fig.5.10: Pin Diagram of GSM Module


5.8.2 Features of GSM Module SIM 300CZ

SIM300 is a Tri-band GSM/GPRS module that works on frequencies EGSM 900 MHz, DCS 1800 MHz

and PCS 1900 MHz. SIM300 features GPRS multi-slot class 10/ class 8 (optional) and supports the GPRS

coding schemes CS-1, CS-2, CS-3 and CS-4. With a small configuration of 40mm x 33mm x 2.85mm,

SIM300 can fit almost all the space requirements in the applications, such as smart phone, PDA phone

and other mobile devices. The physical interface to the mobile application is made through a 60-pin

board-to-board connector, which provides all hardware interfaces between the module and customers’

boards except the RF antenna interface.

The keypad and SPI display interface will give you the flexibility to develop customized

applications.

Serial port and Debug port can help us easily develop our applications.

Two audio channels include two microphones inputs and two speaker outputs. This can be easily

configured by AT command.

The SIM300 provides RF antenna interface with two alternatives: antenna connector and antenna pad.

The antenna connector is MURATA MM9329-2700. And customer’s antenna can be soldered to the

antenna pad. The SIM300 is designed with power saving technique; the current consumption is as low as

2.5mA in SLEEP mode. The SIM300 is integrated with the TCP/IP protocol; extended TCP/IP AT

commands are developed for customers to use the TCP/IP protocol easily, which is very useful for those

data transfer applications[29].

Table 5.2 Feature of GSM Module

Feature Implementation

Power supply Single supply voltage 3.4V – 4.5V

Power saving

Typical power consumption in SLEEP mode to 2.5mA ( BS-PA-

MFRMS=5 )

Frequency bands

SIM300 Tri-band: EGSM 900, DCS 1800, PCS 1900. The SIM300 can search the 3 frequency bands automatically. The frequency bands also can be set by AT command.

Compliant to GSM Phase 2/2+

GSM class Small MS

Transmit power Class 4 (2W) at EGSM 900 Class 1 (1W) at DCS 1800 and PCS 1900


Feature Implementation

GPRS connectivity

GPRS multi-slot class 10 （default）

GPRS multi-slot class 8 (option) GPRS mobile station class B

DATA GPRS: CSD:

GPRS data downlink transfer: max. 85.6 kbps GPRS data uplink transfer: max. 42.8 kbps Coding scheme: CS-1, CS-2, CS-3 and CS-4 SIM300 supports the protocols PAP (Password

Authentication Protocol) usually used for PPP connections. The SIM300 integrates the TCP/IP protocol. Support Packet Switched Broadcast Control Channel

(PBCCH) CSD transmission rates: 2.4, 4.8, 9.6, 14.4 kbps, non-

transparent Unstructured Supplementary Services Data (USSD) support

SMS

MT, MO, CB, Text and PDU mode SMS storage: SIM card

FAX

Group 3 Class 1

SIM interface

Support SIM card: 1.8V, 3V

External antenna

Connected via 50 Ohm antenna connector or antenna pad

Audio features

Speech codec modes: Half Rate (ETS 06.20) Full Rate (ETS 06.10) Enhanced Full Rate (ETS 06.50 / 06.60 / 06.80) Echo suppression

Physical characteristics

Size: 40±0.15 x 33±0.15 x 3.3±0.3mm (including application connector)

40±0.15 x 33±0.15 x 2.85±0.3mm (excluding application connector)

Weight: 8g

Real time clock(RTC)

Implemented

Firmware upgrade

Firmware upgrade by serial port.


5.8.3 Functional Diagram of GSM Module SIM 300CZ

The following figure 5.11 shows a functional diagram of the SIM 300CZ and illustrates the mainly

functional part:

Fig. 5.11 : Functional Diagram of GSM Module SIM 300CZ

The GSM base band engine

Flash and SRAM

The GSM radio frequency part

The antenna interface

The board-to-board interface


5.8 .4 Top view of GSM Module SIM 300CZ The top view of GSM Module is shown in figure 5.12

Fig. 5.12: Top view of GSM Module SIM300CZ 5.8.5 Bottom view of GSM Module SIM 300CZ The bottom view of GSM module is shown in figure5.13

Fig. 5.13: Bottom view of GSM Module SIM300 CZ


5.8.6 Operating Modes of GSM Module SIM 300CZ The table below briefly summarizes the various operating modes [29]. Table 5 .3 Various Operation Mode of GSM Module

Mode Function Normal operation GSM/GPRS SLEEP Module will automatically go into SLEEP mode if DTR

is set to high level and there is no on air and no hardware interrupt (such as GPIO interrupt or data on serial port). In this case, the current consumption of module will reduce to the minimal level. During SLEEP mode, the module can still receive paging message and SMS from the system normally.

GSM IDLE Software is active. Module has registered to the GSM network, and the module is ready to send and receive.

GPRS STANDBY Module is ready for GPRS data transfer, but no data is currently sent or received. In this case, power consumption depends on network settings and GPRS configuration.

GPRS DATA There is GPRS data in transfer (PPP or TCP or UDP). In this case, power consumption is related with network settings (e.g. power control level), uplink / downlink data rates and GPRS configuration (e.g. used multi-slot settings).

5.8. 7 Pin Descriptions of GSM Module

The SIM interface supports the functionality of the GSM Phase 1 specification and also supports the

functionality of the new GSM Phase 2+ specification for FAST 64 kbps SIM. The SIM interface is

powered from an internal regulator in the module having normal voltage 3V. All pins reset as outputs

driving low[26]. Logic levels are as described in below table

Table 5.4 Pin Functions of GSM Module

Name

Pin(GSM

Module)

Function

SIM_VDD 25 SIM Card Power output automatic output on SIM mode one is 3.0V±10%, another is 1.8V±10%. Current is about 10mA.

SIM_DATA 29 SIM Card data I/O

SIM_CLK 31 SIM Card Clock

SIM_RST 27 SIM Card Reset


5.9 Pin Description of the SIM Card

Table 5.5 Pin Functions of SIM Card

Name Description

VDD +3 V DC power supply input from module(optional use by the card).

RESET

Either used itself (reset signal supplied from the interface device) or in combination with an

internal reset control circuit (optional use by the card). If internal reset is implemented, the

voltage supply on Vcc is mandatory

CLOCK Clocking or timing signal (optional use by the card)

GND Ground (reference voltage)

DATA Input or Output for serial data to the integrated circuit inside the card

5.10 SIM Card Holder

For 6 pins SIM card, usually Amphenol C707 10M006 SIM Card holders are used. The diagram of the

SIM card holder is shown in figure 5.14

Fig.5.14: Diagram of the SIM Card Holder


The dialogue between the interface device and the card shall be conducted through the consecutive

operations:

connection and activation of the contacts by the interface device

reset of the card

answer to reset by the card

subsequent information exchange between the card and the interface device

deactivation of the contacts by the interface device

The adapter electronic gets its power supply from the smartcard reader device VCC line or an external 5

V supply can be used [30]. The card slot’s RST line is connected using one of the TTL->RS-232 drivers

in the MAX232 to DCD, so that the software and the reader can easily resynchronize in case of a protocol

error

5.11 Liquid Crystal Display

A liquid crystal display (LCD) is an electronically-modulated optical device shaped into a thin, flat panel

made up of any number of color or monochrome pixels filled with liquid crystals and arrayed in front of a

light source (backlight) or reflector. It is often utilized in battery-powered electronic devices because it

uses very small amounts of electric power. The nematic phase is characterized by the orientational order

of the constituent molecules. The molecular orientation (and hence the material's optical properties) can

be controlled with applied electric fields. Nematics are (still) the most commonly used phase in liquid

crystal displays (LCDs), with many such devices using the twisted nematic geometry.

Fig: 5.15 : Reflective twisted nematic liquid crystal display

Reflective twisted nematic liquid crystal display [31].

1. Polarizing filter film with a vertical axis to polarize light as it enters.


2. Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that

will appear when the LCD is turned ON. Vertical ridges etched on the surface are smooth.

3. Twisted nematic liquid crystal.

4. Glass substrate with common electrode film (ITO) with horizontal ridges to line up with the

horizontal filter.

5. Polarizing filter film with a horizontal axis to block/pass light.

6. Reflective surface to send light back to viewer. (In a backlit LCD, this layer is replaced with a

light source.)

5.12 Outline of LCD Module

Each pixel of a LCD typically consists of a layer of molecules aligned between two transparent

electrodes, and two polarizing filters, the axes of transmission of which are (in most of the cases)

perpendicular to each other. With no actual liquid crystal between the polarizing filters, light passing

through the first filter would be blocked by the second (crossed) polarizer .The surfaces of the electrodes

that are in contact with the liquid crystal material are treated so as to align the liquid crystal molecules in

a particular direction. This treatment typically consists of a thin polymer layer that is unidirectional

rubbed using, for example, a cloth. The direction of the liquid crystal alignment is then defined by the

direction of rubbing. Electrodes are made of a transparent conductor called Indium Tin Oxide

(ITO).Before applying an electric field, the orientation of the liquid crystal molecules is determined by

the alignment at the surfaces. In a twisted nematic device (still the most common liquid crystal device),

the surface alignment directions at the two electrodes are perpendicular to each other, and so the

molecules arrange themselves in a helical structure, or twist. This reduces the rotation of the polarization

of the incident light, and the device appears grey. If the applied voltage is large enough, the liquid crystal

molecules in the center of the layer are almost completely untwisted and the polarization of the incident

light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized

perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the

voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in

varying amounts thus constituting different levels of gray.The optical effect of a twisted emetic device in

the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off

state. Because of this, these devices are usually operated between crossed polarizer such that they appear

bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state).

These devices can also be operated between parallel polarizer, in which case the bright and dark states are

reversed. The voltage-off dark state in this configuration appears blotchy, however, because of small

variations of thickness across the device .Both the liquid crystal material and the alignment layer material


contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time,

this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either

by applying an alternating current or by reversing the polarity of the electric field as the device is

addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied

field)[31]. When a large number of pixels are needed in a display, it is not technically possible to drive

each directly since then each pixel would require independent electrodes. Instead, the display is

multiplexed. In a multiplexed display, electrodes on one side of the display are grouped and wired

together (typically in columns), and each group gets its own voltage source. On the other side, the

electrodes are also grouped (typically in rows), with each group getting a voltage sink. The groups are

designed so each pixel has a unique, unshared combination of source and sink. The electronics or the

software driving the electronics then turns on sinks in sequence, and drives sources for the pixels of each

sink.

5.13 PICBASIC and PICBASIC PRO Compilers

PICBASIC is a compiler developed by COMFILE Technology and is programmed in a form of the

BASIC language. The PICBASIC PRO Compiler (or PBP) makes it even quicker and easier to program

Microchip Technology’s powerful PIC microcontrollers (MCUs). The English-like BASIC language is

much easier to read and write than the quirky Microchip assembly language. The PICBASIC and

PICBASIC PRO Compilers both functions in the same way. The program code, saved as a text file is run

through either the PICBASIC or PICBASIC Pro compiler. The compiler reads through the text file and

creates (or compiles) an equivalent machine code instruction listing (the hex file) of the program. The

machine code is a list of hexadecimal numbers that represents the PICBASIC PRO program. The hex file

is uploaded (or programmed) in to the microcontroller. When the microcontroller started its CPU will run

through the programmed list of hexadecimal numbers that run the PICBASIC Pro program. Uploading the

machine code into the microcontroller is the job of the EPIC programmer board and software. The

PICBASIC PRO (Professional) compiler is considerably more expensive than the standard PICBASIC

compiler. The Pro version offers a richer, more enhanced Basic command syntax than is available in the

Picbasic compiler packages. A few of the additional commands that can be found in the Pro version allow

the use of Interrupts, direct control of Liquid crystal display (LCD) modules, dual-tone multi-frequency

(DTMF) out, and X-10 commands, to name a few. PICBASIC PRO (PBP) is compatible with Windows

98/Me/NT/2000/XP/Vista. It supports over 300 of Microchip's PIC microcontrollers, including the very

latest releases. From the tiny, inexpensive 6-pin parts to the immensely powerful 100-pin parts, PBP

allows you to choose the microcontroller that best fits your application. Used by thousands of engineers,

students, and hobbyists for more than a decade, the PICBASIC PRO Compiler is one of the most popular


development tools ever created for the PIC microcontroller [32]. A new 32-bit version of PBP (PBPL) is

included that offers BIT, BYTE, WORD, and LONG (32-bit, signed)* variable types. This LONG version

is intended for use with the PIC18 family devices. When working with LONGs, the mathematical

operators return signed results in 32-bit, twos-complement format. This allows storage, calculation, and

display of values from -2,147,483,648 to 2,147,483,647 [33].

5.13.1 Comparison Between PICBASIC and PICBASIC Pro Compilers

Table 5.6 Comparison Between PICBASIC and PICBASIC Pro Compilers

PICBASIC™ Compiler PICBASIC PRO™ Compiler

Limited to first 2K code space. Uses all available code space.

Interrupt handlers must be Assembly

language.

Interrupt handler routines may be either PICBASIC

PRO or Assembly.

Uses Peek and Poke commands to access

internal registers and move contents to and

from pre-defined variables.

Internal register names may be used directly, even in

calculations and conditional statements.

Some built-in commands can only be used on

PortB, PortC or GPIO. While all ports may

be accessed with Peek and Poke, some aren't

available for commands like Serout, Pulsin,

etc.

Software-based commands may be used on any

available port/pin. (Commands that utilize a

hardware module are limited to the pins dedicated to

that module. Some pins have special characteristics

that might cause compatibility issues.)

Clock speed pre-defined at 4MHz. Clock speeds from 3.5975 to 48MHz, depending

upon device capabilities.

Most 14-bit core PICmicro® MCUs

supported.

ALL PICmicro® MCUs are supported, including 12-

bit core, 17CXXX, 18CXXX, and 18FXXX.

5.13.2 Additional commands available only in PICBASIC PRO

LCDOut / LCDIn - for controlling parallel interfaced LCD modules. HSerin / HSerout - for controlling the hardware USART available on many PICmicro MCUs. HPWM - for controlling the hardware PWM modules available on many PICmicro MCUs.


Serin2 / Serout2 - RS-232 serial commands capable of sending and receiving ASCII formatted numeric data. Serin2 can be invoked with a timeout parameter to avoid lockup caused by missed serial data.

Select Case - Visual BASIC style case statement. Read Code / Write Code - read and write locations in the code space of self-programming

microcontrollers. OWin / OWout - communicate with One Wire devices. USBin / USBout - access the USB module on specially equipped microcontrollers. Xin / Xout - send and receive X-10 commands for household remote control. ADCin - perform analog-to-digital conversion on devices so equipped.

5.13.3 PICBASIC PRO advantages

Uses 5-10% less code space than standard compiler.

Syntax is less demanding, making Pro easier to learn.

Debug information can be generated for Microchip development tools [33].

5.13.4 PICBASIC PRO Compiler Instruction Set

@ Insert one line of assembly language code. ADCIN Read on-chip analog to digital converter. ASM..ENDASM Insert assembly language code section. BRANCH Computed GOTO (equiv. to ON..GOTO). BRANCHL Branch out of page (long BRANCH). BUTTON Debounce and auto-repeat input on specified pin. CALL Call assembly language subroutine. CLEAR Zero all variables. CLEARWDT Clear (tickle) Watchdog Timer. COUNT Count number of pulses on a pin. DATA Define initial contents of on-chip EEPROM. DEBUG Asynchronous serial output to fixed pin and baud. DEBUGIN Asynchronous serial input from fixed pin and baud. DISABLE Disable ON DEBUG and ON INTERRUPT processing. DISABLE DEBUG Disable ON DEBUG processing. DISABLE INTERRUPT Disable ON INTERRUPT processing. DTMFOUT Produce touch-tones on a pin. EEPROM Define initial contents of on-chip EEPROM. ENABE Enable ON DEBUG and ON INTERRUPT processing. ENABLE DEBUG Enable ON DEBUG processing. ENABLE INTERRUPT Enable ON INTERRUPT processing. END Stop execution and enter low power mode. ERASECODE Erase block of code memory FOR..NEXT Repeatedly execute statements. FREQOUT Produce up to 2 frequencies on a pin. GOSUB Call BASIC subroutine at specified label. GOTO Continue execution at specified label. HIGH Make pin output high. HPWM Output hardware pulse width modulated pulse train.


HSERIN Hardware asynchronous serial input. HSERIN2 Hardware asynchronous serial input, second port. HSEROUT Hardware asynchronous serial output. HSEROUT2 Hardware asynchronous serial output, second port. I2CREAD Read from I2C device. I2CWRITE Write to I2C device. IF..THEN..ELSE..ENDIF Conditionally execute statements. INPUT Make pin an input. LCDIN Read from LCD RAM. LCDOUT Display characters on LCD. LET Assign result of an expression to a variable. LOOKDOWN Search constant table for value. LOOKDOWN2 Search constant / variable table for value. LOOKUP Fetch constant value from table. LOOKUP2 Fetch constant / variable value from table. LOW Make pin output low. NAP Power down processor for short period of time. ON DEBUG Execute BASIC debug monitor. ON INTERRUPT Execute BASIC subroutine on an interrupt. OWIN One-wire input. OWOUT One-wire output. OUTPUT Make pin an output. PAUSE Delay (1mSec resolution). PAUSEUS Delay (1uSec resolution). PEEK Read byte from register. PEEKCODE Read byte from code space POKE Write byte to register. POKECODE Write byte to code space at device programming time POT Read potentiometer on specified pin. PULSIN Measure pulse width on a pin. PULSOUT Generate pulse to a pin. PWM Output pulse width modulated pulse train to pin. RANDOM Generate pseudo-random number. RCTIME Measure pulse width on a pin. READ Read byte from on-chip EEPROM. READCODE Read word from code memory. REPEAT..UNTIL Execute statements until condition is true. RESUME Continue execution after interrupt handling. RETURN Continue at statement following last GOSUB. REVERSE Make output pin an input or an input pin an output. SELECT CASE Compare a variable with different values. SERIN Asynchronous serial input (BS1 style). SERIN2 Asynchronous serial input (BS2 style). SEROUT Asynchronous serial output (BS1 style). SEROUT2 Asynchronous serial output (BS2 style). SHIFTIN Synchronous serial input. SHIFTOUT Synchronous serial output. SLEEP Power down processor for a period of time. SOUND Generate tone or white-noise on specified pin. STOP Stop program execution. SWAP Exchange the values of two variables.


TOGGLE Make pin output and toggle state. USBIN USB input. USBINIT Initialize USB. USBOUT USB output. WHILE..WEND Execute statements while condition is true. WRITE Write byte to on-chip EEPROM. WRITECODE Write word to code memory. XIN X-10 input. XOUT X-10 output0

5.13.5 Functions / Operators

All math operations are unsigned and performed with 16-bit precise

Table 5.7 Various Operators and Functions

Math Operators Description

+ Addition

- Subtraction

* Multiplication

** Top 16 Bits of Multiplication

*/ Middle 16 Bits of Multiplication

/ Division

// Remainder (Modulus)

<< Shift Left

>> Shift Right

ABS Absolute Value*

COS Cosine

DCD 2n Decode

DIG Digit

DIV32 31-bit x 15-bit Divide

MAX Maximum*

MIN Minimum*

NCD Encode

REV Reverse Bits

SIN Sine

SQR Square Root


Math Operators Description

& Bitwise AND

| Bitwise OR

^ Bitwise Exclusive OR

~ Bitwise NOT

&/ Bitwise NOT AND

|/ Bitwise NOT OR

^/ Bitwise NOT Exclusive OR

5.13.6 Structure of a Compiled Program

PBP is designed to be easy to use. Programs can be compiled and run with little thought to PBP's internal

workings. Some people, however, only have confidence in a product when they understand its internal

workings. Others are just plain curious. It describes the files used and output generated by PBP and gives

some idea of exactly what is going on .

5.13.7 Target Specific Headers

Three target specific header files are used when a program is compiled. One is used by PBP, the other two

are included for use by the assembler. A file with the name of the microcontroller followed by the

extension .BAS contains chip specific information needed by PBP. This includes the memory profile of

the chip, which library it uses, and includes for the definition of the variables it needs. For the

PIC18F2550the default microcontroller, the file is named 16F84.BAS.A file with the name of the

microcontroller followed by the extension .INC is included in the generated .ASM file to give the

assembler information about the chip, including the default configuration parameters (oscillator mode,

Watchdog Timer setting, etc.). For the PIC16F84, the file is named 16F84.INC.Finally, the assembler has

its own include file that defines the addresses of the microcontroller registers. This file is usually named

something on the order of M16F84.INC. and is in the INC directory.

5.13 .8 The Library Files

PBP includes a set of library files that contain all of the code and definition files for a particular group of

microcontrollers. In the case of 14-bit core PIC micros, these files start with the name

PBPPIC14.PBPPIC14.LIB contains all of the assembly language subroutines used by the compiler.

PBPPIC14.MAC contains all of the macros that call these subroutines. Most PICBASIC PRO™

commands consist of a macro and an associated library subroutine. PBPPIC14.RAM contains the VAR


statements that allocate the memory needed by the library. PIC14EXT.BAS contains the external

definitions that tell PBP all of the 14-bit core PIC micro register names

5.13.9 PBP Generated Code

A PICBASIC PRO™ compiled program is built in several stages. First PBP creates the .ASM file. It then

builds a custom .MAC file that contains only the macros from the macro library that are used in the .ASM

file. If everything is error free up to this point, it spawns the assembler. The assembler generates its own

set of files. These include the .HEX final output file and possibly listing and debugging files.

5.13.10 ASM File Structure

The ASM file has a very specific structure. Things must be done in a particular order for everything to

work out properly. The first item placed in the file is an equate defining which assembler is to be used,

followed by an INCLUDE to tell the assembler which microprocessor is the target and give it some basic

information, such as the configuration data.Next, all of the variable allocations and aliasing is listed.

EEPROM initialization is next, if called for.An INCLUDE for the macro file is then placed in the file,

followed by an INCLUDE for the library subroutines.Finally, the actual program code is incorporated.

This program code is simply a list of macros that were generated from the PICBASIC PRO™ line.

5. 14 EPIC programmer

EPIC (Explicitly Parallel Instruction Computing) is a 64-bit microprocessor instruction set, jointly

defined and designed by Hewlett Packard and Intel, that provides up to 128 general and floating point unit

registers and uses speculative loading, predication, and explicit parallelism to accomplish its computing

tasks. By comparison, current 32-bit CISC and RISC microprocessor architectures depend on 32-bit

registers, branch prediction, memory latency, and implicit parallelism, which are considered a less

efficient approach in micro architecture design. IA-64 (Intel Architecture-64), Intel's first 64-bit CPU

micro architecture, is based on EPIC. Intel's first implementation, long expected and well-known as

Merced (its code name), was christened with the Itanium brand name in October, 1999. It is expected that

Itanium-based systems will be compatible with versions of existing and future operating systems

including HP-UX, 64-bit Windows, IA-64 Linux, Project Monterey. EPIC programmer consists of

software (EPIC Program) and a programming carrier board (hardware). The EPIC software package has

two executable files one for DOS and another version for Windows. It is the EPIC hardware and software

that take the compiled hex file generated by the compiler and upload it into the microcontroller where it

may be run. The EPIC programmer is compatible with both the PICBasic and PICBasic Pro compilers

[33].


5.14.1 EPIC Programmer for PICmicro controllers Features

Low cost programmer for most PICmicro microcontrollers

Connects to PC parallel printer port

ICSP programming

The programmer has a built-on 18-pin socket for programming 8-, 14- and 18-pin DIP packaged

PICmicro MCUs and must be powered with a power adapter within the range of 15 - 18 Volt. (Before

using the programmer be sure to adjust the programming voltage of 13.5 Volt using the mounted

Potentiometer and a Voltmeter) .

5.14.2 EPICWIN and EPIC Programmer

The EPIC Programmer is an inexpensive microcontroller programmer that will program most PIC micro

microcontrollers (MCUs). Most 8-, 14- and 18-pin PIC micro MCUs may be programmed in the socket

on the EPIC Programmer. Optional adapters are available to program 20-, 28- and 40-pin DIP PIC micro

MCUs, as well as PIC micro MCUs in surface-mount and PLCC packages.

5.14.2.1 Software Installation

The EPIC Programmer files are compressed into a self-extracting file on the disk. They must be

uncompressed before use. To uncompress the files, first a directory should be created on hard drive called

EPIC, or any other name.

5.14.2.2 Hardware Installation

There should be no PIC micro MCUs installed in the EPIC programming socket or any connected

adapter's socket until the programming software is executed and the LED is off. The EPIC Programmer

should be placed on an insulated surface to prevent the shorting out of traces on the bottom.T he EPIC

Programmer is connected to a PC compatible parallel printer port using a 25-pin male to 25-pin female

printer extension cable. The EPIC Programmer uses pins 2-6, 10, and 19-25. A serial cable may not have

all of the necessary connections so it should be assured to use a printer extension cable. If the EPIC

Programmer is powered with the optional AC adapter, it should be plugged it into the power connector on

the programmer and then into a wall outlet. The AC adapter should provide approximately 16V DC at

500ma. If the EPIC Programmer is powered with two 9-volt batteries, then batteries should be snapped

onto the battery snaps. 2-pin shorting jumper should be connected to the 2-pin "Batt ON" posts. It is a


good idea to check the battery voltage from time to time or if there seems to be difficulty programming

parts. The EPIC Plus Programmer should now be powered up and ready to program PIC micro MCUs.

5.14.3 General Operation

The next task is to write the program using any text editor, such as DOS EDIT or Windows NOTEPAD,

and assemble it using the assembler, PM, included on the disk, or MPASM (or MPLAB), available from

Microchip. Instructions for the use of PM are on the included disk.Once the program assembles properly,

the generated .HEX file may be programmed into a PICmicro MCU using the EPIC programming

software. Three versions of the EPIC software are included: two versions for DOS (one command line

and one graphical) and one for Windows 95/98/ME/NT/2000/XP. The Windows 95/98/ME/NT/2000/XP

version should, of course, be run under Windows 95, 98, ME, NT, 2000 or XP. The Windows and

command line DOS versions are more up-to-date than the graphical DOS version and are able to program

more types of PICmicro MCUs.

5.14.4 EPIC for Windows 95/98/ME/NT/2000/XP

First the Windows 95/98/ME/NT/2000/XP version of the EPIC software should be started by navigating

using Explorer to the EPIC directory and double-clicking on EPICWin. Alternatively, a shortcut can be

created to EPIC on desktop. The EPIC software will take a look around to find where the EPIC Plus

Programmer is attached and get it ready to program a PICmicro MCU. If the EPIC Programmer is not

found, all of the above connections should be checked and verified if there is any PICmicro MCU

installed in the programmer or any connected adapter.Once the programming bar is displayed, the device

type should be selected by using the drop-down device selector box to the right of the buttons.The

assembled object (.HEX) file should be opened. Double-click on the appropriate file to load it. Once the

file has been loaded, the proper device characteristics are selected under the Options menu. The Code

Protect is set to OFF before programming a windowed (JW) PICmicro MCU. Code protected windowed

part may not be erased. A PICmicro MCU sould be inserted into the EPIC Programmer or connected

adapter socket. The end of the PICmicro MCU with the notch should be all the way at the Pin 1 end of the

socket, away from the battery connectors. the Program button should be clicked or Run|Program with the

mouse to program the PICmicro MCU.Before programming, the EPIC software optionally does a blank

check to ensure that the part is erased. If the PICmicro MCU is a 18F2550 or another EEPROM or flash

part, it is usually not necessary to erase it before programming. PIC16F7x and PIC18Fxxx devices do

require erasing each time before the MCU may be reprogrammed


5.14.5 EPICWin Controls

The Open speed button opens a .HEX file for programming. The name of an open file appears in the

EPICWin title bar. Previous configuration information will not be altered if Options|Update

Configuration is not checked.

The Save speed button will save the current code, data, ID and configuration information to the

currently open file. If no file has been previously selected, it will prompt for a filename.

The Program speed button will program the current code, data, ID and configuration into the selected

device. It will optionally load the latest version of the .HEX file before programming. The device will be

checked to ensure it is blank before programming, unless Options|Skip Blank Check is checked.

The Verify speed button will compare the current code, data, ID and configuration to the programmed

device. If the information does not match, an error message is displayed. A verify is also done as the

device is being programmed. A code protected device cannot be verified.

The Read speed button will read the current code, data, ID and configuration from the selected device.

The configuration information will not be read if Options|Update Configuration is not checked.

The Blank Check speed button will read the code space to ensure a device is blank. It will not check

the data space, ID, configuration or the oscillator calibration word programmed by the factory into some

devices.

The Erase speed button will erase EEPROM or flash electrically erasable devices. It is grayed out for

devices that cannot be electrically erased.

The Device box allows selection of the device to be programmed. Click the down arrow to the right of the

box to drop down a list of supported devices, and then click on the device. This device information,

including the default device that is selected on start-up, is contained in the file EPIC.INI. This file must be

in the same directory as EPICWIN.EXE. The device should be selected before a .HEX file is opened to

ensure the configuration information is properly interpreted. Devices with parenthesis after them indicate

that they will program either the base version of the part, or the version contained within the parenthesis.


5.14.6 EPIC Win Menus

5.14.6.1 File Menu

File|New clears the EPICWin code, data and ID information. If Options|Update Configuration is checked, the configuration information will also be cleared.

File|Open opens a .HEX file for programming. The name of an open file appears in the EPICWin title

bar. Previous configuration information will not be altered if Options|Update Configuration is not

checked.

File|Save saves the current code, data, ID and configuration information to the currently open file. If no file has been previously selected, it will prompt for a filename.

File|EPIC Port will display the parallel printer port the EPIC Programmer was found on, if Auto is checked. If Auto is not checked, the printer port can be selected manually.

File|Exit exits the program.

5.14.6.2 View Menu

View|Code displays the co de wind ow. This will show the open .HEX file or recently read code information in hexadecimal or ASCII.

View|Configuration displays the device configuration fuse window. Additional configuration fuses for the PIC17C7xx and PIC18Xxxx devices must be set from the drop-down Configuration menu.

View|Data EEPROM displays the data EEPROM window. This will show the open .HEX file or recently read data information in hexadecimal or ASCII. Only devices with on-chip EEPROM data space will read and program this data.

View|ID displays the ID window. This will show the open .HEX file or recently read code information in hexadecimal or ASCII.

View|Serial Number displays a window that allows the serial number to be set and programmed into the device. The serial number is stored in the code space at the specified location, overwriting any code that may already be there, and will be incremented by the Increment By value after each successful programming.

View|Count displays a window showing the number of programming attempts and successes. The count is reset when the software is started, a file is opened, a device is read or the device type is changed.

View|Close All Windows closes any open configuration, code, data, ID or count window.

View|Stay On Top causes the EPICWin bar to float on top of any other windows when checked.


5.14.6.3 Run Menu

Run|Program will program the current code, data, ID and configuration into the selected device. It will optionally load the latest version of the .HEX file before programming. The device will be checked to ensure it is blank before programming, unless Options|Skip Blank Check is checked.

Run|Verify will compare the current code, data, ID and configuration to the programmed device. If the information does not match, an error message is displayed. A verify is also done as the device is being programmed. A code protected device cannot be verified.

Run|Read will read the current code, data, ID and configuration from the selected device. The configuration information will not be read if Options |Update Configuration is not checked.

Run|Blank Check will read the code space to ensure a device is blank. It will not check the data space, ID, configuration or the oscillator calibration word programmed by the factory into some devices.

Run|Erase will erase EEPROM or flash electrically erasable devices. It is grayed out for devices that cannot be electrically erased.

5.14.6.4 Configuration Menu

The configuration fuses are unique to each particular PICmicro MCU.

5.14.6.5 Options Menu

Options|Program/Verify Code allows the device's code space to be programmed and verified when checked. If it is not checked, the device's code space will not be programmed or verified. It will always be read and blank checked, regardless.

Options|Program/Verify Configuration allows the device's configuration fuses to be programmed and verified when checked. If it is not checked, the device's configuration fuses will not be programmed or verified.

Options|Program/Verify Data allows the device's data space, if any, to be programmed and verified when checked. If it is not checked, the device's data space will not be programmed or verified. It will always be read, regardless.

Options|Program/Verify ID allows the device's ID to be programmed and verified when checked. If it is not checked, the device's ID will not be programmed or verified. It will always be read, regardless.

Options|Program/Verify Oscillator Calibration allows the device's oscillator calibration factor location to be programmed and verified when checked. If it is not checked, the device's oscillator calibration factor location will not be programmed or verified. It will always be read, regardless.

Options|Program Serial Number allows a serial number to be programmed into the device when checked. If it is not checked, the serial number will not be programmed. As the serial number is programmed into the code space, Program Code must also be checked to program the serial number.


Options|Update Configuration, when checked, will cause the configuration fuse settings to be updated when opening a file or reading a device. If it is not checked, the configuration fuse settings will not be changed.

Options|Reread File Before Programming, when checked, will cause the latest version of the .HEX file to be loaded before the device is programmed. The configuration fuse settings will also be updated, if Options|Update Configuration is checked. This will override the current settings.

Options|Erase before Programming, when checked, will cause the device to be erased before it is programmed.

Options|Verify after Programming, when checked, will cause the device to be verified as a separate step after programming.

Options|18Fxxx File Data Address * 2, when checked, will multiply the Data EEPROM addresses in the .HEX file times 2 for compatibility with files generated by PBP

Options|Disable Completion Messages will prevent the displaying of operation complete messages at the end of programming, verifying and erasing a device.

Options|Skip Blank Check will prevent blank checking a device before it is programmed when checked.4.1.6.6 Help Menu

Help|Help opens the default browser and displays the HTML help file.

Help|Readme opens the default text editor and displays the README file.

Help|About... displays the program version number and copyright.

5.15 In-Circuit Serial Programming

The circuit serial programming is shown in figure 5.16. The EPIC Programmer may be used for in-circuit

serial programming of serial programmable

Fig: 5.16: In-Circuit Serial Programming


PICmicro MCUs through the 10-pin expansion header J3. Vpp, RB6, RB7 and ground should be

connected as in the following diagram. Any additional connections to /MCLR, RB6 and RB7 should be

designed as to not interfere with in-circuit programming. The cable connecting the EPIC 10-pin header to

the target board should be less that 6 inches long. The drawing shows the pinouts and connections to the

18-pin PIC18F2550 For other PIC MCUs, use their corresponding pin connections.Note: +5 volts should

be supplied to the PICmicro MCU by the target system. The +5 volt and Vdd lines from the EPIC Plus

Programmer header are not intended to power external circuits.

5.16 Photograph /Bottom view/Layout of the System

The photograph of the system are shown in figure 5.17(a) and figure5.17(b)

Fig. 5.17(a): Front Photograph of the Prototype in functional state


Fig.5. 17(b): Bottom View of the System

Result & Verification 116

CHAPTER -6 RESULT AND VERIFICATION

6.1 Objectives

The objectives of the thesis are as follows:

To develop the system with reducing cost and sending the energy meter reading from

consumers residence and receiving it into database server of organization using SMS

technology

Digital energy meter reading will be sent without involvement of human being into the

database server of organization at the starting day of a month.

No meter reader is to be involved for taking the meter reading

The organization will be benefited.

The organization will be corruption free and system loss will be reduced.

The skilled technical persons will be involved with the system.

The accuracy of the meter reading system will be maintained

The reputation of the organization will be enhanced.

Friendly relationship will be established between consumers and organization.

6.2 Required Equipments

6.2.1 Hardware Components

Energy Measuring Chip

Microcontroller

GSM Module

SIM

LCD Display/Monitor

EPIC Programmer board

DC Power Supply(X –former ,IC, Transistor and Capacitor)

Test Board

6.2.2 Software Components

EPIC Win


PIC Basic Pro Software

6.3 Circuit Diagram

The schematic circuit diagram of the system is shown in figure 6.1. The basic parameters of this

circuit are microcontroller, GSM module, Energy Measuring Chip, LCD display and some

interfacing circuits.

Fig. 6.1: Schematic circuit Diagram

In this system microcontroller acts as a brain and control the operation of the whole system using

fixed program that is stored in memory.


6.4 Operation

The figure 6.1 represents the schematic circuit diagram of the system. It’s a microcontroller

based system and microcontroller controls the interfacing equipments functions using fixed

program that is stored in memory. The desire output of the system is to produce data reading in

energy form continuously and sending this reading to the organization at the first day of a month

by SMS method.. The operating mechanism of the system such as energy measuring chip of

digital energy meter produces serial energy data output from analog input by the sequential

action of its consisting parameters that are serially interfaced to the microcontroller.

Microcontroller reads energy data from energy measuring chip .Later microcontroller

accumulate data, calculate data, store data in EEPROM and display data reading on LCD

display each 10 second later. Microcontroller reads time from GSM network via GSM module

and compares this time with setting time. At the starting moment of a month the receiving time

must be equal the setting time according to program and microcontroller provides data reading to

GSM module. The initially microcontroller send previous reading and later send current reading.

GSM module reads data, produce short message on the basis of reading and send message

through mobile communication system. Later the SMS message in GSM Module is deleted by

microcontroller and the meter reading is received by organization server via mobile

communication system such a sequence that means GSM module- BTS-BSC-MSC -GMSC-

MSC-BSC-BTS- Modem - SMS enabler software-database server-1 –SQL-database server-2. .

In fact microcontroller communicates with other equipments in this system by some interfacing

circuits. The basic functions of the interfacing circuits in this system such as

Using Q1 transistor based interfacing circuit microcontroller power on to the GSM

module.

Using Q2 transistor based interfacing circuit GSM module acknowledges to the

microcontroller.

Using zener diode based interfacing circuit microcontroller provides meter reading /

request signal to the GSM module.

Using Q4 & Q5 transistors based interfacing circuit GSM module acknowledgement to

the microcontroller


Using Q3 Transistor based interfacing circuit GSM module takes network information.

The firstly blinking of GSM module LED indicates that the network is not available and

normal blinking of LED indicates that the network is available.

Using Q6 transistor based interfacing circuit microcontroller controls the load

connection with the system.

It may be noted that while microcontroller providing the data reading to the GSM module, if the

electricity is not available then the message sending will be remained stop. Later when the

electricity will come in that case the first priority basic the microcontroller will provide the data

reading to the GSM module and GSM module will do the as usual functions.

6.5 Result

When power supply provided to the circuit, the circuit activated effectively. The Microcontroller

provided the meter reading to the LCD display unit each 10 second later.. Microcontroller

provides the meter reading to the GSM module at the first day of the month. .GSM Module

received the meter reading and produced short message on the basic of meter reading and sent

message through mobile communications systems.

6.6 Discussion

Completed the all works with carefully for achieving the desired result. The system was basically

microcontroller based and microcontroller controls the function of all the equipments. The result

of the work i.e, the digital energy meter reading from the consumer meter was sent to the

organization server using SMS technology. For achieving the desire result, we designed circuit,

wrote program, compiled program and installed program into microcontroller. Later assembled

all hardware components in circuit diagram and was made the connection properly. Lastly it was

produced the net output of the system.

120

CHAPTER-7

ENERGY METER READING TRANSFER TO BILLING STATION 7.1 Introduction This is the time of information technology. In the era of advancement it is possible to send and receive energy meter reading from one to another end of the world in a very short time with minimum cost. In early days due to lack of man power, lack of responsibilities of concern person, unfavorable weather and communication it would not be possible to send this reading from one place to another. In that case people would face a lot of problems and they would deprive from various type of services. For getting the better services mobile phone data communication system and computer may provide massive contribution .In fact now a days the use of mobile phone data communication and computer has been increased that has positively affected the human civilization. In some cases for getting the desired result the mobile phone data communication system and the data terminal equipment are used simultaneously. From data terminal equipment it is possible to send desired data through mobile phone system. Consequently it is also possible to send the data reading to the computer and save corresponding energy consumed reading into the database server in a secured manner. In fact for taking the energy meter reading from GSM network and saving this reading into database server in that case over all work is accomplished by the sequential action of GSM modem, SMS Enabler Software and SQL(Structured Query Language) respectively. 7.2 System Architect of Energy Meter Reading Save into Database Server The figure 7.1 represents the system architect of energy meter reading loading system into database server. The system is composed of GSM network, GSM modem, SMS Enabler Software, database server-1,SQL (Structured, Query Language)and database server-2 parameter. The operating principle of the system such as GSM modem reads the energy meter reading, sender number and time from the GSM network and save these parameters into the SIM or other memory location of this device.

Fig. 7.1: Block Diagram of the System

SMS

Enabler

Software

Database

Server-1

Modem

Energy Meter Reading

SQL Database

Server-2

GSM Network PC

121

Later it is needed to transfer the above mentioned parameters from the SIM to database server-1 In that case SMS Enabler Software is used for accomplishing this work. In fact SMS Enabler Software reads energy meter reading, sender number and time from SIM and load these parameters into the database server-1 corresponding to the column name. Again it is needed to transfer energy meter reading (For sorting the previous kwh, current kwh and prepare net kwh), sender number and time to the database server-2 according to column name from data base server-1. In that case SQL (Structured, Query Language) is used for performing this work. 7.3 Software used for Processing the Energy Meter Reading into Database Server

SMS Enabler Software SQL (Structured Query Language)

7.4 Utility of SMS Enabler Software for processing the Energy Meter Reading SMS Enabler is a multi purpose usable software that supports multiple functions. SMS Enabler is a computer program that automatically support to receive incoming energy meter reading from GSM network using an attached GSM modem to PC .SMS Enabler can a) automatically save, incoming energy meter reading into a database according to desired format. b) forward incoming energy meter reading to a web server via HTTP; c) forward, incoming energy meter reading as emails d) save incoming energy meter reading to a text file(s); 7.5 Key Feature of SMS Enabler Software

The complete feature of SMS Enabler Software are given below: SMS Enabler Software-

Uses a GSM modem, connected to a computer, to receive SMS messages and send replies. The phone/modem can be connected to a PC via cable, Bluetooth or infrared (IR).

Supports automatic saving of received SMS text messages into a database. Supports MS Access, MS SQL Server, My SQL, Oracle databases, as well as other databases through ODBC or OLE DB drivers.

Supports automatically dispatching received SMS text messages to a web server via HTTP, so those messages can be handled by a server-side script. The script can be written in any web programming language, such as PHP, ASP.NET and so forth. Secure HTTP (HTTPS) is also supported.

Supports automatic forwarding of received SMS text messages as email messages to one or more addresses using the SMTP protocol. Messages can

122

be forwarded to different email addresses depending on the content of the message and/or the sender's number.

Allows incoming SMS messages to be automatically saved into a text/CSV file, or multiple files, for real-time processing and logging. Three modes are supported: a) 'single file'; b) 'file per day'; and c) 'file per message'.

Supports automatic SMS message reply to the sender. The reply message text can be predefined in the settings, or generated dynamically by a web script.

Designed to run continuously without user intervention. Automatically reconnects to the phone/modem upon loss of connection. Supports long (linked/concatenated) messages. Supports Unicode SMS messages Logging Supports Windows 2000, Windows XP, Windows Vista, Windows 7, and

Windows Server 2003/2008.

7.6 Utility of SQL for Reformatting the Energy Meter Reading Data into Database Server Structured Query Language is a programming language designed for managing data in relational database management systems (RDBMS).Originally based upon relational algebra and tuple relational calculus, its scope includes data insert, query, update and delete, schema creation and modification, and data access control. Structured Query Language makes relationship between two or more database server in case of data transaction. In this system energy meter reading data firstly store into database server-1 and later store into database server-2 according to desire format. In fact there are two parts of the energy meter reading. One is previous reading and another is current reading.It is needed to be shown in database server-2 in separate mode and prepare net meter reading. This work is accomplished by query operation of Structured Query Language . 7.6.1 Query of Structured Query Language The most common operation in SQL is the query, which is performed with the declarative SELECT statement. SELECT retrieves data from one or more tables, or expressions. Standard SELECT statements have no persistent effects on the database. Some non-standard implementations of SELECT can have persistent effects, such as the SELECT INTO syntax that exists in some databases. Queries allow the user to describe desired data, leaving the database management system (DBMS) responsible for planning, optimizing, and performing the physical operations necessary to produce that result as it chooses.A query includes a list of columns to be included in the final result immediately following the SELECT keyword. An asterisk ("*") can also be used to specify that the query should return all columns of the queried tables. SELECT is the most complex statement in SQL, with optional keywords and clauses that include:

123

The FROM clause which indicates the table(s) from which data is to be retrieved. The FROM clause can include optional JOIN subclauses to specify the rules for joining tables.

The WHERE clause includes a comparison predicate, which restricts the rows returned by the query. The WHERE clause eliminates all rows from the result set for which the comparison predicate does not evaluate to True.

The GROUP BY clause is used to project rows having common values into a smaller set of rows. GROUP BY is often used in conjunction with SQL aggregation functions or to eliminate duplicate rows from a result set. The WHERE clause is applied before the GROUP BY clause.

The HAVING clause includes a predicate used to filter rows resulting from the GROUP BY clause. Because it acts on the results of the GROUP BY clause, aggregation functions can be used in the HAVING clause predicate.

The ORDER BY clause identifies which columns are used to sort the resulting data, and in which direction they should be sorted (options are ascending or descending). Without an ORDER BY clause, the order of rows returned by an SQL query is undefined

7.7 Method of Loading Energy Meter Reading into a Database Server using SMS Enabler Software

SMS Enabler can automatically save incoming energy meter reading directly into a MS Access database. In order to configure SMS Enabler to forward incoming energy meter reading into a MS Access database, it is needed to:(a) create a special table named SMS_IN in database (SMS_IN will store received energy meter reading);(b) specify the connection parameters to database in the settings dialog box in SMS Enabler. The information given below on how to configure SMS Enabler Software with a Microsoft Access database For creating a table named SMS_IN in database to store incoming energy meter reading .

Table 7.1 Format of Database server

SMS_IN Column name Type Description

SMS_TEXT Memo message content SENDER_NUMBER

Text sender's number

SENT_DT Date/time the time when the sender sent the message

It may be configured database connection parameters in SMS Enabler's settings dialog box. Later the setting dialog box may be opened in SMS Enabler and selecting the energy meter reading to database page. It may be checked the save

124

received energy meter reading into a database checkbox. It may be clicked to create connection string, and select Microsoft Access in the menu. A dialog box will open where it can be specified the path to database file(SMS_IN)

Settings dialog box Connection

Modem connection: It may be selected which modem/phone want to use with SMS Enabler, or via which COM port this modem/phone is connected to PC.

Baud rate it may be entered the baud rate to use to connect to modem/phone, or select the appropriate value from the list.

RTS/CTS flow control ; It may be selected "On" to enable RTS/CTS flow control. Auto start SMS Enabler to automatically start receiving when it launches. Save received energy meter reading into a database: SMS Enabler to

automatically save incoming energy meter reading into a database.

125

Connection string :A connection string is a string that specifies information about a data source and the means of connecting to it. It may be created connection string' for a MS Access database,

String encoding : It may be Specifies which encoding is used to save string data into the database.

Maximum number of retries: The maximum number of attempts to save a received energy meter reading into the database, after the first attempt fails.

Retry timeout (in seconds) The number of seconds to wait before retrying, if the previous attempt to save a received energy meter reading into the database

7.8 Transfer Data from Database Server-1 to Database Server-2 Using SQL (Structured Query Language )

The table [7. 2] represents the format of database server-1 and file name of the format is SMS_IN. This table contains three columns where the column name sms_text, sender_number and sent_dt respectively. The energy meter reading load into first column, sender number load into second column and time load into third column from GSM network via GSM Modem and SMS Enabler software.

126

Table 7.2 Energy Meter Reading Load into Database server-1

SMS_IN sms_text sender_number sent_dt

previous kwh=0.002606 recent kwh=0.004178 01933480062 1/10/2011 10:11:00 AM previous kwh=0.002609 recent kwh=0.004180 01718207476 1/10/2011 11:15:00 AM previous kwh=0.002611recent kwh=0.004180 01718891619 1/10/2011 12:10:00 PM

For transferring data according to sorting base from database server-1 to database server-2, a query has been written in SQL that is shown in double star mark. ***INSERT INTO Meter_Reading INSERT INTO Meter_Reading ( Previous_kwh, Current_kwh, Net_kwh, sender_number, sent_dt ) SELECT Mid([sms_text],14,8), Mid([sms_text],34,8), Mid([sms_text],34,8)-Mid([sms_text],14,8), sender_number, sent_dt FROM SMS_IN; ;*** Only opening the query and all data transfer from database server-1 to database server-2 according to sorting. The result of the operation is shown in table[ 7 .3]. The table 2 represents the format of database server-2 and file name of the format is Meter_Number. This table contains five columns where the column name Previous_kwn, Current_kwh, Net_kwh ,sender_number and sent_dt respectively.

Table7.3 Energy Meter Reading Load into Database server-2

.

Meter_Reading Previous_kwh Current_kwh Net_kwh sender_number sent_dt

0.002606 0.004178 0.001572 01933480062 1/10/2011 10:11:00 AM 0.002609 0.004180 0.001571 01718207476 1/10/2011 11:15:00 AM 0.002611 .004180 0.001569 01718891619 1/10/2011 12:10:00 PM

Discussion 127

CHAPTER-8 DISCUSSION

The fundamental work of the thesis includes generation, transmission, and reception of digital

energy meter reading into database server for providing the better service to the consumer and

secondary aim of this thesis is to reduce cost, remove corruption, produce job opportunity for the

skilled technical person, overcome the system loss, increase reputation of organization and

finally make friendly relationship between consumers and organization .

The reason for doing this work was that there are three types of energy meter reading systems

available in Bangladesh, such as analog energy meter, digital energy meter and digital prepaid

energy meter reading system. In case of analog energy meter and digital energy meter reading

system, a meter reader has to be attended in front of meter at the end of month or any specific

date of the month for taking the meter reading .Sometimes they can not take the meter reading

timely due to lack of man power, due to lack of negligence, unfavorable weather and

communication. In that case system loss increases and negatively influences the organization.

Whereas in case of digital prepaid meter system, meter card has to be installed into the meter.

When book value of the card is equal to the energy consumed by the meter then meter

automatically shuts down. Later, meter card has to be purchased from the market or

organization. But sometimes meter cards are not available in the market and the consumer faces

automatic trouble of load shedding. Not only that there is a common practice in Bangladesh that

the meter readers and also consumers are involved in illegal procedure and corruption. The

corruption of meter readers and consumers are considered as system loss by authority that has

also negative influence on the organization and therefore, the reputation of the organization will

be reduced. GSM and SMS technology which have been utilized in this thesis work reliably and

confidentially and provides the better service.

8.1 Limitation

The limitation of the thesis work are as follows:

The digital energy meter will be installed in such a place where the network should be

available. Because without mobile network, it is not possible to send energy meter

reading to the organization server from consumer residence by SMS method.

Discussion 128

The digital energy meter will be installed in such a place where the temperature should

remain within reasonable range to be matched with the equipment. Otherwise

microcontroller may do malfunctions.

The price of the microcontroller based main circuit is too high. Actually GSM module is

an additional part of the consumer meter. It is much difficult to purchase the meter for

those who are poor consumers. So It should be provided by organization.

The Microcontroller based main circuit is sensitive as it may be damaged by mishandling.

Overall system function depends upon hardware and software. So any problem of the two

items, system may face interruption for generation and transmission of short message.

Those who are illiterate consumers firstly may accept the meter reading by SMS method

with confusion. In that case, it is needed to motivate them by the organization.

8.2 Achievement

The achievement of the thesis is to receive the digital energy meter reading into database server

sent from the consumers premises. This result has already been achieved in the present work.

Before achieving this result, some knowledge on purely dc power supply production, equipment,

digital energy meter mechanism, microcontroller mechanism, GSM module, SIM, GSM

technology, SMS technology, programming language and also software function have to be

achieved. On the basis of this achievement, a lot of options are available for the extension of

future works.

8.3 Recommendation for Future Work

In extension of future work, it is possible to disconnect load from meters from organization if the consumers are not found to pay the bill in time or for doing any offensive work that is not certified by the electricity supply authority. As an extension of future work it is possible to prepare electricity bill by utilizing the recent SMS energy meter reading in database server and sends to the consumers mobile where the present status of the meter reading can be checked instantaneously.

-End-

References 129

References [1] GSM Module: GSM Notification Module http://www.g-e.ee/files/manuals/gsm- n2_eng.pdf/

(Accessed on 16th June 2009).

[2] Trosby F. SMS,thestrage duckling of GSM.Telekronikk; 2004;3:pp187-194

[3] Remote Meter system, Meterhttp://homepage.usask.ca/~tak488/SMS_Remote Meter.pdf

(11-11-2009)

[4] Global System for Mobile Communication http://en.wikipedia.org/wiki/GSM(03 11 2009)

[5] Short Message Service http://en.wikipedia.org/wiki/Short_message_service(03-11-2009). [6] Microcontroller http://en.wikipedia.org/wiki/Microcontroller(18-10-009 ) [7] PIC Microcontroller http://en.wikipedia.org/wiki/PIC_microcontroller(18-10-009 ) [8] SIM http://en.wikipedia.org/wiki/Subscriber_Identity_Module(18-10-009) [9] Energy meter http://en.wikipedia.org/wiki/Energy_meter(18-10-009)

[10] LCD http://en.wikipedia.org/wiki/Liquid_crystal_display(19-10-009) [11] PIC BASIC PRO SOFTWARE http://www.warburtech.com/compilers/picbasic.pro/

(02-011-2009) [12] EPIC Win Software, Ford Equity Research. EPIC for Windows v5.00 – Download and

Install Instructions http://www.fordupdate.com/epic.htm//(Accessed on 17th June 2009). [13] SMS Enabler Software www. smsenabler.com(Accessed on 03.06.2011) [14] Structured Query Language http://en.wikipedia.org/wiki/ Structured _ Query _ Language

(Accessed on 16.05.2011)

[15] SMS what where and how http://www.wirelessdevnet.com/channels/sms/features/sms. html (27-10-2009)

[16] GSM BASIC http://media.wiley.com/product_data/excerpt/49/04700169/0470016949.pdf

(25-10-009).

[17] Introduction to SMS Technology.com.hk/document/networking/sms_via_email.pdf (27-10-2009

[18] SMS protocol http://www.3gpp2.org/Public_html/specs/CS0015-0.pdf(5-11-2009)

[19] gsm user service http://www.tutorialspoint.com/gsm/ gsm_user_services .htm (05- 11-2009) [20] GSM Specification http://www.tutorialspoint.co m/gsm/gsm_specification.htm (5-11-2009)

[21] Microcontroller Basic Stam http://a.parsons.edu/~cherdlick/courses/archInt_stamp

References 130

.pdf-(08-11-2009

[22] Programming Pic Microcontroller http://seniord.ece.iastate.edu/dec0604/ index_files/ tutorialDec0604.pdf(08-11-2009)

[23] Karataş P, Aksoy M. Microcontroller based Home Automation. Proceedings of

International Conference on Intelligent Knowledge Systems (IKS-2004), 16-20

August, 2004. http://www Ikss.org/iks-2004/pdf/E0109.pdf//(Accessed on 17th

June 2009).

[24] Microcontroller Features http://www.esacademy.com/automation/faq/primer/4.htm (08-11-220)

[25] Microcontroller http://ww1.microchip.com/downloads/en/ DeviceDoc/39632D

.pdf (20-10-009)

[26] Energy Measuring Chip(ADE7756) analog.com/static/importedfiles/product_ highlights/828090860_features_2003New.pdf (Accessed on13-10-2009)

[27] ADE7756AN Energy Measuring Chip http://pdf1.alldatasheet.com/datasheetpdf/

view/113531/AD/ADE7756AN.html

[28] Power Supply Technical Guide. http://www.xppower.com/ (Accessed on 26th June

2009).

[29] SIM Technology Group Ltd. Wireless Module Solution. http://www.sim.com/

(Accessed on 22nd June 2009).

[30] Amphenol Smart Card Connectors.: http:// www.mouser.com/amphenol-tuchel/

(Accesed on 22nd June 2009).

[31] Gray GW, Kelly SM. Liquid crystals for twisted nematic display devices. Journal

of Material Chemistry. 1999; Vol. 9: pp. 2037-2050.

[32] PICBASIC Compiler. http:// www.melabs.com/ (Accessed on 30th June 2009)

[33] PICBASIC Pro Compiler http://www.imagesco.com/microcontroller/pbpman.pdf//

(Accessed on 17th June 2009).

Md Ranju Sardar - DUET

Documents

Transcript of Md Ranju Sardar - DUET