14092013094858 sms based notice board project

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KEYWORDS

ACC : Accumulator

B : B Register

PSW : Program Status Word

SP : Stack Pointer

DPTR : Data Pointer

DPL : Low byte

DPH : High byte

P0 : Port 0

P1 : Port 1

P2 : Port 2

P3 : Port 3

IE : Interrupt Enable control

IP : Interrupt Priority control

TMOD : Timer/counter Mode control

TCON : Timer/counter control

T2CON : Timer/counter 2 control

T2MOD : Timer/counter mode2 control

TH0 : Timer/counter 0high byte

TL0 : Timer /counter 0low byte

TH1 : Timer/counter 1high byte

TL1 : Timer/counter 1low byte

TH2 : Timer/counter 2 high byte

TL2 : Timer/counter 2 low byte

SCON : Serial control

SBUF : Serial data buffer

PCON : Power control

IR : Infra Red


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INDEX

ACKNOWLEDGE ------------------------------------ 6ABSTRACT ------------------------------------ 7

I.INTRODUCTION 9

II. LITERATURE SURVEY2.1 Motivation 112.2 Background 112.3 Aim 112.4 Requirement Analysis 12

2.4.1 Hardware Requirements 12

2.4.2 Software Requirements 122.5 Scope 122.6 Advantages 13

III.DESIGN METHODOLOGY3.1 Hardware system design 15

3.1.1 Block level design of SMS notice board 153.1.2 Selection of Hardware 163.1.3 Design consideration of Microcontroller 16

3.1.3.1 8051 163.1.3.2 Internal architecture of P89V51RD2FN 17

3.1.3.2.1 I/O ports 183.1.3.2.2 Interrupt controls 193.1.3.2.3 Bus controllers 203.1.3.2.4 Memory organization 213.1.3.2.5 Registers in 8051 213.1.3.2.6 Oscillator 23

3.1.3.3 Features 243.1.4 Serial communication 25

3.1.4.1 Introduction 253.1.4.2 Baud rate 26

3.1.5 Hardware design of LCD 26

3.1.5.1 LCD screen 273.1.5.2 Features 303.1.5.3 Pin configuration 303.1.5.4 Specifications 313.1.5.5 Functionality of LCD in project 33

3.1.6 GSM Module 333.1.6.1 Wireless MODEM 343.1.6.2 GSM/GPRS MODEM 343.1.6.3 GSM/GPRS Module 353.1.6.4 Mobile Station 363.1.6.5 Difference between GSM Mobile and GSM Module 36

3.1.6.6 Applications of GSM/GPRS Module 373.1.6.7 AT Commands 37


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3.1.6.8 Command, information response and result code 373.1.6.9 AT Commands syntax 383.1.6.10 Interfacing MODEM/Module with WINDOWS 40

3.1.7 Max232 403.1.7.1 Pin Configuration 41

3.1.8 RS232 (Female port) 413.1.8.1 Voltage levels 413.1.8.2 Pin configuration 423.1.8.3 DB9 interfacing microcontroller using MAX232 42

3.1.9 Serial port connector 433.1.10 Resistors 433.1.11 Capacitors 433.1.12 Crystal oscillators 443.1.13 Power supply 45

3.2 Software design 463.2.1 Liquid Crystal Display 46

3.2.1.1 Checking busy state of LCD 463.2.1.2 LCD Initialization 433.2.1.3 Writing commands for display flow chart 47

3.2.2.1 Flow chart of the project 50

IV. IMPLEMENTATION4.1 Hardware implementation 52

4.1.1 Complete Schematic of SMS notice board 524.1.2 Connections of P89V51RD2FN 534.1.3 Pin connections of LCD 54

4.1.4 MAX232, DB9 and GSM connections 54

V. SOFTWARE IMPLEMENTATION5.1 JHD204A LCD interfacing 56

5.1.1 Initialization of LCD 565.1.2 Initialization sequence code 565.1.3 Display the data into the LCD 565.1.4 Writing the command to display 575.1.5 Reading data to display 57

VI. APPLICATION, ADVANTAGES AND FUTURE SCOPE6.1 Advantages. 596.2 Applications 596.3 Future Enhancements 59

VII. DEBUGGING TECHNIQUES7.1 KEIL micro vision debugger 62

7.1.1 Introduction to KEIL IDE 627.1.2 Features 627.1.3 Steps to follow while writing program in KEIL 63

7.2 Flash Magic 647.2.1 Features 64

7.3 Null MODEM checking (HYPER TERMINAL) 65

7.4 Hardware debugging techniques 66CONCLUSION 66


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RESULT 67

VIII. BIBILOGRAPHY 67IX. APPENDIX

KEIL MICROVISION IDE 68FLASH MAGIC 76SET UP OF HYPER TERMINAL 79COMPLETE CODE 82


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ABSTRACT

Notice Board is primary thing in any institution / organization or public utility places

like bus stations, railway stations and parks. But sticking various notices day-to-day is a

difficult process. A separate person is required to take care of this notices display. This

project deals about an advanced hi-tech wireless notice board. Notice Board is primary thing

in any institution / organization or public utility places like bus stations, railway stations and

parks. But sticking various notices day-to-day is a difficult process. A separate person is

required to take care of this notices display. This project deals about an advanced hi-tech

wireless notice board.

The project is built around the 8051 micro controller from Atmel. This micro

controller provides all the functionality of the display and wireless control. It also takes care

of creating different display effects for given text. Display is obtained on LCD (16X4) Matrix

Display Array on a printed circuit board. A GSM/CDMA Mobile Can is used to enter the

required text or notice. The scrolling speed of the text also can be changed according to user

requirement. After entering the text the SMS is sent to the no which is connected to the LCD

display. At any time the user can add or remove or alter the text according to his requirement.

At the receiving end the GSM modem which is connected to the Max 232 receives the

message and is connected to the microcontroller 8051. The message is displayed on the LCD(16X4) Matrix Display Array. This project uses regulated 5V, 500mA power supply. 7805

three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier

is used to rectify the ac output of secondary of 230/12V step down transformer.

Keywords: Embedded System, Micro controller, Cross-compiler and Debugging.


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CHAPTER-1


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CHAPTER - I

INTRODUCTION

Notice Board is primary thing in any institution / organization or public utility places

like bus stations, railway stations and parks. But sticking various notices day-to-day is a

difficult process. A separate person is required to take care of this notices display. This

project deals about an advanced hi-tech wireless notice board. An embedded system is a

combination of software and hardware to perform a dedicated task. Some of the main devices

used in embedded products are Microprocessors and Microcontrollers, Microprocessors are

commonly referred to as general purpose processors as they simply accept the inputs, process

it and give the output. In contrast, a microcontroller not only accepts the data as inputs but

also manipulates it, interfaces the data with various devices, controls the data and thus finally

gives the result. As everyone in this competitive world prefers to make the things easy and

simple to handle, this project sets an example to some extent.

Now a days every advertisement is going to be digital. The big shops and shopping

centers are using the digital moving displays now. In Railway station and bus stands

everything that is ticket information, platform number etc is displaying in digital moving

display. But in these displays if they wants to change the message or style they have to go

there and connect the display to PC or laptop. Suppose the same message if the person wants

to display in main centers of the cities means he have to go there with laptop and change the

message by connecting into PC. This project we can use mainly for police or army .I.e.

displays will be connected to all the main centers in city if they wants to display messages

about something crucial within 5 minute, they cant .So keeping in this mind we are

designing a new display system which can access remotely, we are using the GSM

technology to access the displays is one of the new technology in the embedded field to

make the communication between microcontroller and mobile. This project is a remote notice

board with MODEM connected to it, so if the user wants to display some messages, he will

send the messages in SMS format the MODEM in the display system will receive the

message and update the display according to the message. For every message received from

the user mobile, the system will check for the password and if the password is correct the

controller will display the message

GSM based Control System implements the emerging applications of the GSM

technology. Using GSM networks, a control system has been proposed that will act as an

embedded system which can monitor and control appliances and other devices locally using

built-in input and output peripherals.

GSM (Global System for Mobile Communications): It is a cellular communication standard.


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SMS (Short Message Service): It is a service available on most digital mobile phones that

permit the sending of short messages (also known as text messaging service).

.

CHAPTER-2


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CHAPTER- II

LITERATURE SURVEY

2.1 MOTIVATION:

In present digitalized world, the exploit of GSM and SMS is popular. Notice Board is

primary thing in any institution / organization or public utility places like bus stations,

railway stations and parks. But sticking various notices day-to-day is a difficult process. A

separate person is required to take care of this notices display. A new display using the GSM

technology to access the displays is one of the new technologies in the embedded field to

make the communication between microcontroller and mobile.

From the past many years we are seeing the notices of the college, companies, offices

is usually displayed on the normal board having number of notices written on the same board.

So we were thinking that if all these notices are displayed at the same place one by one

except occupying the whole board area. So we come to the conclusion to design a Notice

board such that it can fulfill the requirements such as less manual operation, same notice can

be displayed at the various places at the same time, the notice (board display) should be

visible from maximum area or distance, compact and compatible, easy handling.

2.2 BACKGROUND:

Market research analysts are predicting that the wireless technologies will eventually

become more widespread than the various wired solutions. The wireless communications

present the ideal solution for the home network .This increasing demand of getting wireless

can be seen not only in the field communication but also in the transferring information and

data. The cell phones which are the best example of wireless data and voice transfer can be

used for many other purposes that can replace the traditional system. One simple way of

using this wireless communication is to use a simple cell phone for sending messages. Our

administrator uses a simple GSM based handset for sending messages to different display

stations which are located far away from him. The GSM modem used at the receiver end is

used to receive the messages and LCD to display them. As we are using mobile for sending

messages, its easy to handle and operate. As it's a wireless transmission the system has very

less errors and maintenance. With greater efficiency we can display the messages at various

places like public transports, crowded cities and advertisement of chain restaurants. We can

use this displaying system at distant area where our wire or manpower can go easily.GSMand GPRS based designs have developed another innovative and Public Utility Product for


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mass communication. This is a Wireless Scrolling Message Electronic Display Board, which

displays the messages, received as SMS or GPRS Packet.

2.3 AIM:

To design and implement a GSM based wireless message display system using 8051

microcontroller coded in EMBEDDED C language.

2.4 Requirement Analysis:

2.4.1 Hardware requirements

The components those are required for Smart Energy Meter project is given below.

1. Micro Controller (P89V51RD2BN).2. MAX 232.3. DB9 or RS232 connector.4. Power supply.5. LCD display.6. GSM module.7. SIM.

2.4.2 Software requirements

1. KEIL Vision 4IDE C51 Embedded Cross Compiler.2. FLASH MAGIC Philips Serial ISP programming utility.

2.5 SCOPE:

The scope of this project is to introduce a new technology for notice board displaysystem using GSM. A user can send a message from anywhere in the world. Multilingualdisplay can be another added variation of the project. The display boards are one of the singlemost important media for information transfer to the maximum number of end users. Thisfeature can be added by programming the microcontroller to use different encoding decodingschemes in different areas as per the local language. This will ensure the increase in thenumber of informed users. Graphical display can also be considered as a long term butachievable and target able output. MMS technology along with relatively high endmicrocontrollers to carry on the tasks of graphics encoding and decoding along with a more

expansive bank of usable memory can make this task a walk in the park.


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2.6 Advantages:

A lot of interaction and information sharing occurs. No printing & photocopying costs. No manual effort. Helps to retain and develop the knowledge base of your college or office. Saves Time, Energy and finally Environment.


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CHAPTER-3


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CHAPTER - III

DESIGN METHODOLOGY

3.1 Hardware System Design:

3.1. 1 Block level design.

The block diagram of GSM based message display system is given below

Fig 3.1: Functional block diagram of SMS notice board.


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3.1.2 SELECTION OF HARDWARE:

The hardware selected must be such a way that

Low cost Low power consumption, small, fast Continually reacts to changes in the systems environment Must compute certain results in real-time without delay Simple design Easy maintainability and interoperability Bug-free/Correctness, safety, many more.

3.1.3 DESIGN CONSIDERATIONS OFMICROCONTROLLER

WHY P89V51RD2FN?

The system requirements and control specifications clearly rule out the use of 16, 32bit microcontrollers.

The P89V51RD2xx contains non-volatile 64KB Flash program memory that is bothparallel programmable and serial In-System and In-Application Programmable.

In-System Programming (ISP) allows the user to download new code while themicrocontroller sits in the application.

In-Application Programming (IAP) means that the microcontroller fetches newprogram code and reprograms itself while in the system. This allows for remoteprogramming over a modem link. A default serial loader (boot loader) program inROM allows serial In-System programming of the Flash memory via the UARTwithout the need for a loader in the Flash code. For In-Application Programming, theuser program erases and reprograms the Flash memory by use of standard routinescontained in ROM.

3.1.3.1 8051

The 8051 is an 8 bit microcontroller originally developed by Intel in 1980. It is one ofthe most popular microcontrollers in the world for its high performance, rich instruction setand low cost. This device is a Single-Chip 8-Bit Microcontroller manufactured in anadvanced CMOS process and is a derivative of the 8051 microcontroller family. Theinstruction set is 100% compatible with the 8051 instruction set. Three criteria in choosingthe microcontrollers are as follows:

1. Meeting the computing needs of the task at hand efficiently and costeffectively.


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2. Availability of software development tools such as compliers, assemblers, anddebuggers.

3. Wide availability and reliable sources of the microcontroller.

Some of the features that have made the 8051 popular are:

64 KB on chip program memory. 128 bytes on chip data memory (RAM). 4 register banks. 128 user defined software flags. Four 8-bit data bus 16-bit address bus 32 general purpose registers each of 8 bits 16 bit timers (usually 2, but may have more, or less). 3 internal and 2 external interrupts. Bit as well as byte addressable RAM area of 16 bytes. Four 8-bit ports, (short models have two 8-bit ports). 16-bit program counter and data pointer. 1 Microsecond instruction cycle with 12 MHz Crystal.

8051 models may also have a number of special, model-specific features, such as UARTs,ADC, Op Amps, etc...

3.1.3.2 Internal architecture of P89C51RD2XX

The P89C51RD2xx contains a non-volatile 8KB/16KB/32KB/64KB Flash programmemory that is both parallel programmable and serial In-System and In-ApplicationProgrammable.In-System Programming (ISP) allows the user to download new code whilethe microcontroller sits in the application. In-Application Programming (IAP) means that themicrocontroller fetches new program code and reprograms itself while in the system.


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The internal architecture of P89C51RD2FN microcontroller with suitable diagram

Fig 3.2: Internal architecture of P89C51RD2FN.

3.1.3.2.1 I/O ports:All 8051 microcontrollers have 4 I/O ports each comprising 8 bits which can be

configured as inputs or outputs. Accordingly, in total of 32 input/output pins enabling themicrocontroller to be connected to peripheral devices are available for use.Pin configuration,


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i.e. whether it is to be configured as an input (1) or an output (0), depends on its logic state. Inorder to configure a microcontroller pin as an input, it is necessary to apply logic zero (0) toappropriate I/O port bit. In this case, voltage level on appropriate pin will be 0.

The 4I/O ports of 8051 are designated as port 0, port 1, port 2, and port 3. All

these I/O ports have different functions and conditions while connecting to externalperipherals.

3.1.3.2.1. a Port 0 (P0)-The P0 port is characterized by two functions. If external memory is used then the

lower address byte (addresses A0-A7) is applied on it. Otherwise, all bits of this port areconfigured as inputs/outputs. The other function is expressed when it is configured as anoutput. Unlike other ports consisting of pins with built-in pull-up resistor connected by itsend to 5 V power supply; pins of this port have this resistor left out. If any pin of this port isconfigured as an input then it acts as if it floats. Such an input has unlimited input

resistance and undetermined potential.When the pin is configured as an output, it acts as anopen drain. By applying logic 0 to a port bit, the appropriate pin will be connected toground (0V). By applying logic 1, the external output will keep on floating. In order toapply logic 1 (5V) on this output pin, it is necessary to built in an external pull-up resistor.

3.1.3.2.1. b Port 1 (P1)-P1 is a true I/O port, because it doesn't have any alternative functions as is the case

with P0, but can be configured as general I/O only. It has a pull-up resistor built-in and iscompletely compatible with TTL circuits.

3.1.3.2.1. c Port 2 (P2)-P2 acts similarly to P0 when external memory is used. Pins of this port occupyaddresses intended for external memory chip. This time it is about the higher address bytewith addresses A8-A15. When no memory is added, this port can be used as a generalinput/output port showing features similar to P1.

3.1.3.2.1. d Port 3 (P3)-All port pins can be used as general I/O, but they also have an alternative function. In

order to use these alternative functions, a logic one (1) must be applied to appropriate bit ofthe P3 register. In terms of hardware, this port is similar to P0, with the difference that its

pins have a pull-up resistor built-in.

3.1.3.2.2 Interrupts controls:

There are 7 kinds of interrupt controllers that 8051 handles. They are as follows.

1. INT0 external interrupt.2. INT1 external interrupt.3. Timer 04. Timer 15. Reset.6. Transmitted interrupt (TXD).7.

Received interrupt (RXD).


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There are two types of external hardware interrupts. Pin 12 (P3.2) and pin 13 (P3.3) of the8051, designated as INT0 and INT1, are used as external hardware interrupts. Upon theactivation of these pins, the 8051 gets interrupted in whatever it is doing and jumps to thevector table to perform the interrupt service routines (ISR).

Timer 0 and timer 1 interrupts can be used in pooling method. In this method, wehave to wait until the TF is raised. The problem with this method is that the microcontroller istied down the controller. If the timer interrupt in the IE register is enabled, whenever thetimer rolls over, TF is raised, and the microcontroller is interrupted in whatever it is doing,and jumps to the interrupts vector table to service the ISR.

Reset pin is an input pin and is active high (normally low). Upon applying a highpulse to this pin, the microcontroller will reset and terminate all activities. This is often

referred to as power-on reset. In order for RESET input to be effective, it must have aminimum duration of two machine cycles. In other words, the high pulse must be high for aminimum of two machine cycles before it is allowed to go low. TXD and RXD are serialcommunication interrupts.

3.1.3.2.3 BUS CONTROLS

The main bus controllers available in 8051 are ALE, EA, RST and PSEN.

ALE (Address Latch Enable):Output pulse for latching the low byte of the address during an access to external

memory. In normal operation, ALE is emitted twice every machine cycle, and can be used forexternal timing or clocking. Note that one ALE pulse is skipped during each access toexternal data memory. ALE can be disabled by setting SFR auxiliary.0. With this bit set,ALE will be active only during a MOVX instruction.

EA (External Access Enable/Programming Supply Voltage):EA must be externally held low to enable the device to fetch code from external

program memory locations. If EA is held high, the device executes from internal programmemory. The value on the EA pin is latched when RST is released and any subsequent

changes have no effect. This pin also receives the programming supply voltage (VPP) duringFlash programming.

RST (Reset):A high on this pin for two machine cycles while the oscillator is running resets the

device. An internal resistor to VSS permits a power-on reset using only an external capacitorto VCC.

PSEN (Program Store Enable):The read strobe to external program memory. When executing code from the external

program memory, PSEN is activated twice each machine cycle, except that two PSEN

activations are skipped during each access to external data memory. PSEN is not activatedduring fetches from internal program memory.


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3.1.3.2.4 Memory organization

The 8051 has two types of memory and these are Program Memory and DataMemory. Program Memory (ROM) is used to permanently save the program being executed,while Data Memory (RAM) is used for temporarily storing data and intermediate resultscreated and used during the operation of the microcontroller. Depending on the model in use(we are still talking about the 8051 microcontroller family in general) at most a few Kb ofROM and 128 or 256 bytes of RAM is used. All 8051 microcontrollers have a 16-bitaddressing bus and are capable of addressing 64 kb memory. It is neither a mistake nor a bigambition of engineers who were working on basic core development. It is a matter of smartmemory organization which makes these microcontrollers a real programmers goody.

3.1.3.2.4. a Program memory

The first models of the 8051 microcontroller family did not have internal programmemory. It was added as an external separate chip. These models are recognizable by theirlabel beginning with 803 (for example 8031 or 8032). All later models have a few KbyteROM embedded. Even though such an amount of memory is sufficient for writing most ofthe programs, there are situations when it is necessary to use additional memory as well. Atypical example is so called lookup tables. They are used in cases when equations describingsome processes are too complicated or when there is no time for solving them. In such casesall necessary estimates and approximates are executed in advance and the final results are putin the tables (similar to logarithmic tables).

3.1.3.2.4. b Data memory

Data Memory is used for temporarily storing data and intermediate results created andused during the operation of the microcontroller. Besides, RAM memory built in the 8051family includes many registers such as hardware counters and timers, input/output ports,serial data buffers etc. The previous models had 256 RAM locations, while for the latermodels this number was incremented by additional 128 registers. However, the first 256

memory locations (addresses 0-FFh) are the heart of memory common to all the modelsbelonging to the 8051 family.

3.1.3.2.5 Registers in 8051

In the CPU, registers are used to store information temporarily. That informationcould be a byte of data to be processed, or an address pointing to the data to be fetched. Thevast majority of 8051 registers are 8- bit registers. In the 8051 there is only one data type: 8

bits. With an 8-bit data type, any data larger than 8 bits must be broken into 8- bit chunks

before it is processed. The most widely used registers of the 8051 are A(Accumulator), B,and SPF (special function registers) and PSW (Program Status Word).


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A register is a general-purpose register used for storing intermediate results obtainedduring operation. Prior to executing an instruction upon any number or operand it isnecessary to store it in the accumulator first. All results obtained from arithmetical operations

performed by the ALU are stored in the accumulator. Data to be moved from one register toanother must go through the accumulator. In other words, the A register is the mostcommonly used register and it is impossible to imagine a microcontroller without it. Morethan half instructions used by the 8051 microcontroller use somehow the accumulator.Multiplication and division can be performed only upon numbers stored in the A and Bregisters. All other instructions in the program can use this register as a spare accumulator(A).

3.1.3.2.5. a R Registers (R0-R7)

This is a common name for 8 general-purpose registers (R0, R1, R2 ...R7). Eventhough they are not true SFRs, they deserve to be discussed here because of their purpose.They occupy 4 banks within RAM. Similar to the accumulator, they are used for temporarystoring variables and intermediate results during operation. Which one of these banks is to beactive depends on two bits of the PSW Register. Active bank is a bank the registers of whichare currently used.

3.1.3.2.5. b SFR(Special Function Registers)

Special Function Registers (SFRs) are a sort of control table used for running andmonitoring the operation of the microcontroller. Each of these registers as well as each bitthey include, has its name, address in the scope of RAM and precisely defined purpose suchas timer control, interrupt control, serial communication control etc. Even though there are128 memory locations intended to be occupied by them, the basic core, shared by all types of8051 microcontrollers, has only 21 such registers.

3.1.3.2.5.c PROGRAM STATUS WORD (PSW):

CY: Carry out from accumulator MSB of ALU operand AC: Auxiliary carry for BCD operations FO: General purpose RS1 & RS0: For register banks selection ( RB0-RB3) OV: Overflow flag P: Parity of accumulator set by hardware to 1 if it contains odd no of 1s


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Table 3.1.The contents of (RS1-RS0) enable the working register banks

Carry flag:

Carry flag is set whenever there is carry out from the MSB. This flag is after 8bitADD/SUB operation. It can also be set to 1 or 0 directly using SETB C or CLR C

Auxiliary carry:

If there is a carry from D3 to D4 position during Add/Sub operation, this bitwill set. Otherwise, it is cleared. This flag is used for BCD operations.

Parity flag reflects the number of 1s in A. If A contains an odd number of 1s,then P=1. Therefore P=0, if A has an even number of 1 s.

Overflow flag:

This flag is set whenever the result of a signed number operation is too large to beaccommodated in 7 bits, causing the higher order bit to overflow into the sign bit.

3.1.3.2.6 Oscillator:

The microcontroller used in this project, P89C51RD2FN requires a baud rate of 9600.To acquire this baud rate, an 11.0592 MHz crystal must be connected between 19th and 20th

pins of controller. The determination of machine cycle frequency and Baud rate is as follows.

MCF = (XTL freq / 12)

= (11.0592 * 10^6) / 12

= 921.6 KHz

Baud rate = MCF/32

RS 1 RS 0 BANKS AND REGISTERS

0 0 BANK 0 (00H-07H)

0 1 BANK 1 (08H0FH)

1 0 BANK 2 (10H-17H)

1 1 BANK 3 (18H-1FH)


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= (921.6 10^3) / 32

= 28800 Hz

Where MCF = Machine Cycle Frequency,

XTL = Crystal.

To synchronize with timer1 (TH1) to set the baud rate as 9600 we need to set thoseregister value as -3 (decimal) or FD (Hexadecimal) so as to divide the baud rate i.e..28800Hz should be dividing with the decimal value of TH1 to get 9600 value.

Fig 3.3: Oscillator Connections

C1, C2 = 33pF.

3.1.3.3 FEATURES

80C51 Central Processing Unit On chip Flash Program Memory with In-System Programming (ISP) and In-

Application Programming

Boot ROM contains low level Flash programming routines for downloading via theUART

Can be programmed by the end-user application(IAP)


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Supports 6-clock/12 clock mode via parallel programmer(default clock mode afterChip Erase is 12-clock)

Speed up to 20MHz with 6-clock cycles per machine cycle(40MHz equivalent performance), up to 33MHz with 12 clocks per machine cycle

RAM expandable externally to 64Kbytes Four interrupt priority levels Seven interrupt sources Four 8-bit I/O ports Full-duplex enhanced UART 8-Bit ALU , with 2 registers A & B 11 bit program counter & data pointer 8-Bit program status word 8 bit stack pointer 4registers banks, each containing 8 registers 16bytes , which may be addressed at bit level 80 bytes of general purpose data Two 16 bit timer/counterT0 & T1Control registersTCON, TMOD, SCON, PCON and IP & IE oscillator & clock circuits.

3.1.4 SERIAL COMMUNICATION

3.1.4.1 Introduction

In order to connect microcontroller to a modem or a pc to modem a serial port is used.Serial is a very common protocol for device communication that is standard on almost everyPC. Most computers include two RS-232 based serial ports. Serial is also a commoncommunication protocol that is used by many devices for instrumentation; numerous GPIB-compatible devices also come with an RS232 port. Furthermore, serial communication can beused for data acquisition in conjunction with a remote sampling device.

Typically, serial is used to transmit ASCII data. Communication is completed using 3transmission lines. (1) Ground, (2) Transmit and (3) Receive. Since serial is asynchronous,the port is able to transmit data on one line while receiving data on another. Other lines areavailable for handshaking, but are not required. The important serial characteristics are baudrate, data bits, stop bits, and parity. For two ports to communicate, these parameters much

match.Serial communication is a popular means of transmitting data between a computer and

a peripheral device such as a programmable instrument or even another one bit at a time, overa single communication line to a receiver. You can use this method when data transfer ratesare low or you must transfer data over long distances. Serial communication is popular

because most computers have one or more serial ports, so no extra hardware is needed otherthan a cable to connect the instrument to the computer or two computers together.

Any device you connect to the serial port will need the serial transmission convertedback to parallel so that it can be used. In serial communication, the data will be sent from onesystem to another in bit by bit notation. Serial Ports come in two sizes, there are the D-Type 25 pin connector and the D-Type 9 Pin connector both of which are male on the back ofthe PC, and thus you will require a female connector on your device. The RS-232 and RS-485come under serial communication.


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3.1.4.2 Baud Rate:

It is a speed measurement for communication. It indicates the number of bit transfersper second. For example, 300 baud is 300 bits per second. When a clock cycle is referred itmeans the baud rate. For example, if the protocol calls for a 4800 baud rate, then the clock isrunning at 4800Hz. This means that the serial port is sampling the data line at 4800Hz.Common baud rates for telephone lines are 12200, 28800 and 33600. Baud rates greater thanthese are possible, but these rates reduce the distance by which devices can be separated.These high baud rates are used for device communication where the devices are locatedtogether, as is typically the case with GPIB devices.

3.1.5 HARDWARE DESIGN OF LCD

The LCD (Liquid Crystal Display) used to display the output to the user in the form ofGUI (Graphic User Interface) and a mono chromatic display. LCD used in this project isJHD204A series.There are 16 pins in all. They are numbered from left to right 1 to 16 (if youare reading from the backside). LCD shown above is marked to indicate which the 1st pinwas and which the 16th was.

In our project, we use a JHD204A LCD Display which has 4 rows and 20 characters.It contains internal 1 byte latch. It has a better contrast and a wider viewing angle. To developa protocol to interface this LCD with 89V51 first we have to understand how they functions.These displays contain two internal byte-wide registers, one for command and second forcharacters to be displayed. There are three control signals called R/W, RS and EN. Select Bymaking RS signal 0 you can send different commands to display. These commands are usedto initialize LCD, to display pattern, to shift cursor or screen etc. You can see the markingsright next to 1st and 16th pins. The 20by4 LCD with connections is as given below.


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Fig 3.4: Pin configuration of LCD

3.1.5.1 LCD screen:-

LCD screen consists of two lines with 20 characters each. Each character consists of5*7 dot matrix. Contrast on display depends on the power supply voltage and whethermessages are displayed in one or two lines. For that reason, variable voltage 0-Vdd is appliedon pin marked as VEE. Trimmer potentiometer is usually used for that purpose. Some versions

of displays have built in backlight (blue or green diodes). When used during operating, aresistor for current limitation should be used (like with any LE diode)

The main control pins on JHD204A are data lines, read or write and enable.

LCD is finding wide spread use replacing LEDs (seven segment LEDs or other multisegment LEDs) because of the following reasons:1. The ability to display numbers, characters and graphics. This is in contrast to LEDs,

which are limited to numbers and a few characters.2. Incorporation of a refreshing controller into the LCD, thereby relieving the CPU of

the task of refreshing the LCD. In contrast, the LED must be refreshed by the CPU tokeep displaying the data.

3. Ease of programming for characters and graphics.4. These components are specialized for being used with the microcontrollers, which

means that they cannot be activated by standard IC circuits. They are used for writingdifferent messages on a miniature LCD.


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Fig 3.5: LCD Display

3.1.5.1. a Data lines (D0-D7):The data lines are connected to the parallel port of the microcontroller. While

connecting the data lines to port0 no pull up resistors are required. These data lines are usedto pass the data from CPU i.e. controller to LCD internal memory and to pass commandsfrom LCD to CPU.Pin 7 is the Least Significant Bit (LSB) and pin 14 is the Most SignificantBit (MSB) of the data inputs. If you want to display some number or letter on the display, youhave to input the appropriate codes for that character on these pins. These pins are also usedfor giving certain commands to the display like clearing the display or moving the cursor to adifferent location. Upon giving the correct signals to the 3 control pins, the character codes orthe commands that you have given to the Data pins will be written to the display or executed

by the LCD respectively. To make it easier to give the appropriate inputs to these pin, i

recommend wiring up a DIP switch to these pins.

3.1.5.1. b Read and write:Generally, we always use the LCD to show things on the screen. However, in some

rare cases, we may need to read from the LCD what it is displaying. In such cases, the R/Wpin is used. However, this function is beyond the scope of post and will not be explained. Forall practical purposes, the R/W pin has to be permanently connected to GND.

The timing diagram for write and read operation of JHD204A is as follows

Write operation:


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Fig 3.6: Timing diagram of write operation in LCD.

Read operation:

Fig 3.7: Timing diagram of read operation in LCD.

3.1.5.1. c Enable Pin:The enable pin has a very simple function. It is just the clock input for the LCD. The

instruction or the character data at the data pins (D0-D7) is processed by the LCD on the

falling edge of this pin. The Enable pin should be normally held at Vcc by a pull up resistor.When a momentary button switch is pressed, the Pin goes low and back to high again whenyou leave the switch. Your instruction or character will be executed on the falling edge of the

pulse. (i.e. the moment the switch closes).

3.1.5.1. d Reset pin:The LCD has basically two operating modes:Instruction mode and Character

Mode. Depending on the status of this pin, the data on the 8 data pins (D0-D7) is treated aseither an instruction or as character data. You have to activate the command mode if youwant to give an Instruction to the LCD. Example Clear the display, Move cursor tohome etc. You have to activate the character mode if you want to tell the LCD to display

some character. To set the LCD in Instruction mode, you set the 4th pin of the LCD (R/S) toGND. To put it in character mode, you connect it to Vcc.


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3.1.5.2 Features

RS232 compatible serial interface (2400 & 9600 Baud Selectable) Externally selectable serial polarities (Inverted & Non-Inverted) Serially controllable contrast and backlight levels 8 user programmable custom characters 16 Byte serial receive buffer

3.1.5.3 Pin Configuration:

There are pins along one side of the small printed board used for connection to themicrocontroller. There are total of 16 pins marked with numbers .Their function is describedin the table below:

Table 3.2 Pin Connections Description

Pins 18Description

Pins 9 -16Description

Pin1 Ground Pin9D2 (Not Used in

4bit operation)

Pin2 VCC (+5) Pin10D3 (Not Used in

4bit operation)

Pin3 Contrast Pin11 D4

Pin4Data/Comman

d (R/S)Pin12 D5

Pin5Read/Write

(W)Pin13 D6

Pin6 Enable (E1) Pin14 D7

Pin7

D0 (Not Used

in 4bit

operation)

Pin15VCC

(LEDSV+)

Pin8

D1 (Not Used

in 4bit

operation)

Pin16 Ground


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3.1.5.4 SPECIFICATIONS:

Number of Characters: 20 characters x 4 Lines Character Table: English-European (RS in Datasheet) Module dimension: 98.0x60.0x14.0 (MAX) View area: 76.0x25.2mm Active area: 56.2 x 11.5 mm Dot size: 0.6 x 0.66 mm Dot pitch: 0.60 x 0.70 mm Character size: 2.95 x 4.75 mm Character pitch: 3.55 x 5.94 mm LCD type: TN,STN(YELLOW GREEN,GREY,B/W) Duty: 1/16 View direction: Wide viewing angle

To start with LCD the user should initialize it first which should be programmed with

its LCD commands. The LCD commands are given


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Table 3.3 Commands for LCD

CODE COMMANDS TO THE LCD

1 Clear display screen

2 Return home

4 Shift cursor to left

5 Shift display right

6 Shift cursor to right

7 Shift display left

8 Display off, cursor off

A Display off, cursor on

C Display on, cursor off

E Display on, cursor blinking

F Display off, cursor blinking

10 Shift cursor position to left

14 Shift cursor position to right

18 Shift entire display left

1c Shift entire display right

80 Force cursor to begin in 1st row

C0 Force cursor to begin in 2nd

row

38 2 lines &5x7 matrix


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Fig 3.8: LCD Interface with P89C51RD2XX

3.1.5.5 Functionality of LCD in this project:

LCD is used to display any message. After switching ON the power then it displays as Notice board. By receiving the message then it displays command signal received. Then the actual message will be displayed.

3.1.6 GSM MODULE:

GSM/GPRS module is used to establish communication between a computer and aGSM-GPRS system. Global System for Mobile communication (GSM) is an architectureused for mobile communication in most of the countries. Global Packet Radio Service(GPRS) is an extension of GSM that enables higher data transmission rate. GSM/GPRSmodule consists of a GSM/GPRS modem assembled together with power supply circuit andcommunication interfaces (like RS-232, USB, etc) for computer. The MODEM is the soul ofsuch modules.


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Fig 3.9: GSM/GPRS Module

3.1.6.1 Wireless MODEMs:

Wireless MODEMs are the MODEM devices that generate, transmit or decode data

from a cellular network, for establishing communication between the cellular network and thecomputer. These are manufactured for specific cellular network (GSM/UMTS/CDMA) orspecific cellular data standard (GSM/UMTS/GPRS/EDGE/HSDPA) or technology(GPS/SIM). Wireless MODEMs like other MODEM devices use serial communication tointerface with and need Hayes compatible AT commands for communication with thecomputer (any microprocessor or microcontroller system).

Fig 3.10: Applications of wireless MODEM.

3.1.6.2 GSM/GPRS MODEM

GSM/GPRS MODEM is a class of wireless MODEM devices that are designed forcommunication of a computer with the GSM and GPRS network. It requires a SIM(Subscriber Identity Module) card just like mobile phones to activate communication with the

network. Also they have IMEI (International Mobile Equipment Identity) number similar to
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mobile phones for their identification. A GSM/GPRS MODEM can perform the followingoperations:

1. Receive, send or delete SMS messages in a SIM.2. Read, add, search phonebook entries of the SIM.

3. Make, Receive, or reject a voice call.

The MODEM needs AT commands, for interacting with processor or controller,which are communicated through serial communication. These commands are sent by thecontroller/processor. The MODEM sends back a result after it receives a command. DifferentAT commands supported by the MODEM can be sent by the processor/controller/computerto interact with the GSM and GPRS cellular network.

3.1.6.3 GSM/GPRS Module

A GSM/GPRS module assembles a GSM/GPRS modem with standardcommunication interfaces like RS-232 (Serial Port), USB etc., so that it can be easilyinterfaced with a computer or a microprocessor / microcontroller based system. The powersupply circuit is also built in the module that can be activated by using a suitable adaptor.

Fig 3.11: GSM module


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3.1.6.4 Mobile Station (Cell phones and SIM)

A mobile phone and Subscriber Identity Module (SIM) together form a mobilestation. It is the user equipment that communicates with the mobile network. A mobile phonecomprises of Mobile Termination, Terminal Equipment and Terminal Adapter.

Mobile Termination is interfaced with the GSM mobile network and is controlled by abaseband processor. It handles access to SIM, speech encoding and decoding, signaling andother network related tasks. The Terminal Equipment is an application processor that dealswith handling operations related to keypad, screen, phone memory and other hardware andsoftware services embedded into the handset. The Terminal Adapter establishescommunication between the Terminal Equipment and the Mobile Termination using ATcommands. The communication with the network in a GSM/GPRS mobile is carried out bythe baseband processor.

3.1.6.5 Difference between GSM mobile and GSM/GPRS module

A GSM mobile is a complete system in itself with embedded processors that arededicated to provide an interface between the user and the mobile network. The ATcommands are served between the processors of the mobile termination and the terminalequipment. The mobile handset can also be equipped with a USB interface to connect with acomputer, but it may or may not support AT commands from the computer or an external

processor/controller.

The GSM/GPRS module, on the other hand, always needs a computer or externalprocessor/controller to receive AT commands from. GSM/GPRS module itself does notprovide any interface between the user and the network, but the computer to which module isconnected is the interface between user and network.

An advantage that GSM/GPRS modules offer is that they support concatenated SMS whichmay not be supported in some GSM mobile handsets. Also some mobile handsets cantreceive MMS when connected to a computer.


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3.1.6.6 Applications of GSM/GPRS module

The GSM/GPRS module demonstrates the use of AT commands. They can feature allthe functionalities of a mobile phone through computer like making and receiving calls, SMS,MMS etc. These are mainly employed for computer based SMS and MMS services.

3.1.6.7 AT Commands

AT commands are used to control MODEMs. AT is the abbreviation for Attention.These commands come from Hayes commands that were used by the Hayes smart modems.The Hayes commands started with AT to indicate the attention from the MODEM. The dialup and wireless MODEMs (devices that involve machine to machine communication) needAT commands to interact with a computer. These include the Hayes command set as a subset,along with other extended AT commands.

AT commands with a GSM/GPRS MODEM or mobile phone can be used to access following

information and services:1. Information and configuration pertaining to mobile device or MODEM and SIM card.2. SMS services.3. MMS services.4. Fax services.5. Data and Voice link over mobile network.

The Hayes subset commands are called the basic commands and the commands specific to aGSM network are called extended AT commands.

3.1.6.8 Command, Information response and Result Codes:The AT commands are sent by the computer to the MODEM/ mobile phone. The MODEMsends back an Information Response i.e. the information requested by or pertaining to theaction initiated by the AT command. This is followed by a Result Code. The result code tellsabout the successful execution of that command.


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There are also unsolicited Result Codes that are returned automatically by the MODEM tonotify the occurrence of an event. For example the reception of a SMS will force MODEM toreturn an unsolicited result code.

3.1.6.9 AT commands syntax

Case Sensitivity -The AT commands are generally used in uppercase letters. However some MODEMs andmobile phones allow both uppercase and small case letters.

Single Command -The AT commands include a prefix AT which indicates the beginning of the command toMODEM; and a carriage return which indicates the end of the command.

However string AT itself is not the part of the command. For example in ATD, D is thecommand name not ATD.The extended AT commands have a + in the command name. For example: AT+CGMI

Command Line -Multiple AT commands can be sent to MODEM in a single command line. The commands ina line are separated by a semi-colon (;).

For example: AT+CGMI; +CBS


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String in Command Line -Strings in a command line are enclosed in double quotes.For example: AT+CGML=ALL

Information Response and Result CodeThe Information Response and Result Codes, returned by the MODEM, have a carriagereturn and line feed in the beginning as well as at the end.

For example:

OKERROR+CBC: 0, 60 etc.

Sequence of Execution -In the command line, the command appearing first is executed first. The execution thenfollows for second appeared command and so on. The execution of commands in a command

line takes place in sequential manner.

If an error occurs in the execution of a command, an error result code is returned by theMODEM and the execution of the command line is terminated irrespective of presence ofother commands next in the command line.

Types of commands:There are four types of AT commands:

1) Test commands2) Read commands3) Set commands

4) Execution commandsFor more details, see AT Commands.

Different Result Codes:

RESULT CODE DESCRIPTION

OK Successful Execution of a command

ERROR Execution of a command failed

+CMS ERROR Message service failure, is returned with an error code
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Unsoli cited Resul t Codes

+CDS Notify receipt of SMS status report of a new message to computer

+CDSI Notify receipt of SMS status report of a new message and its

location in memory to computer+CMT Notify forwarding of a new SMS to computer

+CMTI Notify receipt of SMS status report of a new message and its

location in memory to computer

Fig 3.10 Commands used in GSM

3.1.6.10 Interfacing MODEM/Mobile phone with Windows platform

The Windows (XP and lower versions) comes with an application calledHyperTerminal for data communication through serial port of the computer. The interfacingof the GSM/GPRS module with the serial port of the computer involves following steps:

1) Connect RS-232 port of GSM module with the serial port of the computer. Insert a SIM cardin the module.

2) Open HyperTerminal from Start -> All Programs -> Accessories -> Communications ->

HyperTerminal.3) Enter a name for the connection and press OK.4) Now select the communication port (COM) at which GSM module is connected.5) Create a new connection set on HyperTerminal. Set parameters, like baud rate as 9600,

handshaking mode as none, parity bit as none, stop bit as 1 and data bit as 8.

3.1.7 MAX 232:

Max232 IC is a specialized circuit which makes standard voltages as requiredby RS232 standards. This IC provides best noise rejection and very reliable againstdischarges and short circuits. MAX232 IC chips are commonly referred to as line drivers.

To ensure data transfer between PC and microcontroller, the baud rate and voltagelevels of Microcontroller and PC should be the same. The voltage levels of microcontrollerare logic1 and logic 0 i.e., logic 1 is +5V and logic 0 is 0V. But for PC, RS232 voltage levelsare considered and they are: logic 1 is taken as -3V to -25V and logic 0 as +3V to +25V. So,in order to equal these voltage levels, MAX232 IC is used. Thus this IC converts RS232voltage levels to microcontroller voltage levels and vice versa.


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3.1.7.1 Pin Configuration:

Fig 3.9: Pin diagram of MAX 232 IC

3.1.8 RS 232(Female Port)

RS-232 is the component which is used to connect system (pc) to microcontroller.RS-232 (Recommended Standard 232) is the traditional name for a series of standards

for serial binary single-ended data and control signals connecting between a DTE (DataTerminal Equipment) and aDCE(Data Circuit- terminating Equipment). It is commonly usedin computer serial ports. The standard defines the electrical characteristics and timing of

signals, the meaning of signals, and the physical size and pinout of connectors.RS232 is limited to point-to-point connections between PC serial ports and devices.

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

3.1.8.1 Voltage levels:

The RS-232 standard defines the voltage levels that correspond to logical one andlogical zero levels for the data transmission and the control signal lines.

For data transmission lines (TxD, RxD and their secondary channel equivalents) logicone is defined as a negative voltage, the signal condition is called marking, and has thefunctional significance. Logic zero is positive and the signal condition is termed spacing.

Table 3.4: indicating voltage levels for DB 9 connector

Logic level Voltage level

1 -10V

0 10V


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3.1.8.2 PIN CONFIGURATION

Fig 3.10: DB9 Connector with pinout

3.1.8.3 DB9 INTERFACING WITH MICROCONTROLLER USING MAX 232:

Fig 3.11:DB9 interfacing with microcontroller using MAX 232

3.1.9 Serial port connector:

The microcontroller is connected to the pc via a serial communication port. The serialcommunication port is a combination of a female port and a male port. The male port isconnected to the DB-9 connector connected to the microcontroller while the female port is

connected to the serial port of the pc.


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Fig 3.12: serial port connector

3.1.10 Resistors:

A resistor is a two-terminal passive electronic component that implements electricalresistance as a circuit element. When a voltage V is applied across the terminals of a resistor,a current I will flow through the resistor in direct proportion to that voltage. This constant of

proportionality is called conductance, G. The reciprocal of the conductance is known as theresistance R, since, with a given voltage V, a larger value of R further "resists" the flow ofcurrent I as given by Ohm's law:

Fig 3.19: Resistors

Practical resistors can be made of various compounds and films, as well as resistancewire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are alsoimplemented within integrated circuits, particularly analog devices, and can also beintegrated into hybrid and printed circuits.

3.1.11 Capacitors:

A capacitor (formerly known as condenser) is a device for storing electric charge. The

forms of practical capacitors vary widely, but all contain at least two conductors separated by


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a non-conductor. Capacitors used as parts of electrical systems, for example, consist of metalfoils separated by a layer of insulating film.

A capacitor is a passive electronic component consisting of a pair of conductorsseparated by a dielectric (insulator). When there is a potential difference (voltage) across the

conductors, a static electric field develops across the dielectric, causing positive charge tocollect on one plate and negative charge on the other plate. Energy is stored in theelectrostatic field. An ideal capacitor is characterized by a single constant value, capacitance,measured in farads. This is the ratio of the electric charge on each conductor to the potentialdifference between them.

Fig 3.20: capacitors

Capacitors are widely used in electronic circuits for blocking direct current whileallowing alternating current to pass, in filter networks, for smoothing the output of powersupplies, in the resonant circuits that tune radios to particular frequencies and for many other

purposes.

The capacitor is a reasonably general model for electric fields within electric circuits.

An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of

charge Q on each conductor to the voltage Vbetween them:

3.1.12 Crystal oscillator:

A crystal oscillator is an electronic oscillator circuit that uses the mechanicalresonance of a vibrating crystal of piezoelectric material to create an electrical signal with avery precise frequency. This frequency is commonly used to keep track of time (as in quartzwristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilizefrequencies for radio transmitters and receivers. The most common type of piezoelectricresonator used is the quartz crystal, so oscillator circuits designed around them becameknown as "crystal oscillators."


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Fig 3.21: crystal oscillator

Quartz crystals are manufactured for frequencies from a few tens of kilohertz to tensof megahertz. More than two billion (2109) crystals are manufactured annually. Most areused for consumer devices such as wristwatches, clocks, radios, computers, and cell phones.Quartz crystals are also found inside test and measurement equipment, such as counters,signal generators, and oscilloscopes.

3.1.13 Power supply:

Most 9-volt adapter units work by converting 110 volts of alternating current, or AC,electrical power into 9 volts of direct current, or DC, losing some energy in the process. Theadapter then supplies DC power to an electronic device through a cord.

Parts

A 9-volt adapter contains several internal components that deliver the powersafely, including a filter capacitor and a rectifier. Some contain fuses; if not, themanufacturer puts a fuse in the electronic device instead,

Conversion

Nine-volt adapters accomplish the actual AC/DC conversion using the rectifiercircuit. The rectifier uses diodes that only permit electricity to move in onedirection. This process generates some heat, causing the adapter to become warm.Some 9-volt adapters contain grating in the plastic to release excess heat.

Effects

An adapter can influence the size and weight of the electronic device, making itsmaller and lighter, because the device doesn't have to convert AC power to 9volts. Also, if retailers sell the adapter separately, the device's initial cost maydecrease.


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Fig 3.22 Power supply.

3.2 Software design:

3.2.1 Liquid Crystal Display

3.2.1.1 Initializing the LCD

Before you using the LCD, the program must initialize and configure it. This isaccomplished by sending a number of initialization instructions to the LCD.

The first instruction to send is the no of data for the LCD i.e., with an 8-bit or 4-bitdata bus. The other thing need to specify is display matrix; in the selected LCD it is a 5x8dot character font. These two options are selected by sending the command 38h to the LCDas a command. The command can give to the LCD by invoking the pre defined function calllcd_cmd with passing parameters value of 38H, the syntax for the same can be given likelcd_cmd (0x38).

3.2.1.2 Checking the busy status of the LCD

3.2.1.2.1 Busy Flag (BF):

When the busy flag is high or 1 the module is performing an internal operation andthe next instruction will not be accepted. The RS=0 is used to check the Busy flag bit too seeif the LCD is ready to receive information. The Busy flag is D7 and can be read when R/W =1 and RS = 0, as follows: if R/W = 1, RS= 0.When D7=1 (busy flag), the LCD is busy taking

care of internal operations and will not accept any new information. When D7=0, the LCD isready to receive new information.
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3.2.1.2.1.1 Busy flag flowchart

Fig 3.22: Busy flag flowchart

3.2.1.3. Writing command to the Display

lcd_command(0x38);delay(100);lcd_command(0x80);delay(100);lcd_command(0xc0);delay(100);lcd_command(0x0e);delay(100);

void lcd_command(unsigned char value){

chdata=value;rs=0;rw=0;

en=1;delay(100);en=0;

}

To give a command to perform some special functions like move to position, clearLCD ,blink the curser etc. the instruction sequence must follow like first instruction must beset in the data bus set RS signal to logic 0 and enabling the LCD will receive the data . Afterfinishing the instruction sequence the application must wait till the LCD completes theinstruction by checking the LCD Busy status.


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3.2.1.4. Writing command display flow chart

Fig 3.23: Writing command display flow chart

1. Check the Busy flag bit2. Set the instruction in data lines (if it is writing)3.Set RS bit to logic 1 to 04. Set R/W bit is to low

6. Set En line to high7. Set line to low

3.2.1.5. Displaying the data in to the LCD

Writing the string in the LCD, to get the result first the address at which the string has todisplay on the screen is given as command followed by displaying the individual charactersas LCD data .That finishes the data to be display in the LCD.


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The complete flow chart representation of LCD working process is as follows:

Fig 3.24: Flow chart for the LCD function.


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3.2.2 Flowchart for the project

Fig 3.25 Flow chart of GSM based wireless notice board


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CHAPTER - 4


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CHAPTER4

IMPLEMENTATION

4.1 HARDWARE IMPLEMENTATION

4.1.1 Complete Schematic of GSM based wireless message display system

Fig 4.1: Complete Schematic of GSM based wireless message display system


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4.1.2 Connections of P89V51RD2BN

The pin configuration of P89V51RD2XX:-

Fig 4.2: Pin diagram of P89V51RD2BN

In this project the microcontroller is connected to MAX232, LCD, and GSM.

The connections of microcontroller are given briefly below:

The reset pin is connected to the 9 th pin (RST) of P89V51RD2BN, as it is used for setreset the program.

While the 10pin is connected to the 12th pin of MAX232. 11th pin of controller is connected to the 11th pin of MAX232. The crystal oscillator which gives a frequency of 11.0592 MHz for the required Baud

rate of 9600Hz to the microcontroller. This crystal oscillator is connected in between18th (XALT 1) and 19th (XALT 2) pins of P89V51RD2BN controller.

The 20th pin of controller is grounded. The pins from 21st to 28th (port 2 data lines) are used for the connections for data lines

of LCD. The 29th pin is connected to a switch so as to dump and execute the program.

Whenever the PSEN pin is pressed then we can execute the last dumped program,likewise when 29th pin is connected to VCC then code can be dumped into thecontroller.

Address Latch Enable pin (30th pin) of controller is connected to the ground hence noconnections need not to be given to this pin.


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External Access Enable or programming supply voltage should be latched when RSTis released and any subsequent changes have no effect. This pin also receives the

programming supply voltage (VPP) during Flash programming. Hence the pin 31stmust be connected to high i.e. VCC.

4.1.3 Pin connections of LCDThe LCD used for output display is JHD204A series. The detailed connections of

LCD is described briefly as

The 1st and 2nd pins of JHD204A LCD are connected to ground and high voltage VCCrespectively.

3rd pin of LCD is connected to the centre pin of the potentiometer or variable resistorso as to adjust the contrast of LCD.

The 4th, 5th, 6th pins are connected to 26th (P 2.5), 27th (P 2.6), 28th (P 2.7) pins of themicrocontroller respectively.

The 7th to 14th pins are data pins and are connected to the 39 th (P 0.0) to 32nd (P 0.7)pins of the microcontroller respectively.

The 15th and 16th pins are used for backlight purpose. 15th pin is connected to VCC and16th pin to ground.

Fig 4.3: connection of LCD with P89V51RD2BN.

4.1.4 MAX232, DB9 AND GSM CONNECTION:

MAX232 and DB9 connector plays a key role in program dumping andcommunication between project kit to the PC host.

Capacitor C10 of capacitance 1Uf is connected across 1st and 3rd pins of MAX232 andC9 of capacitance 1Uf is connected in between 4th and 5th pins.

Charge pump capacitors are required for the MAX232 to work it as voltage levelshifter. The charge pump capacitors used here are C7 and C8 whose capacitance is1Uf. C7 is connected between 6th pin and ground, while C8 is connected across 2nd

pin of MAX232 and Vcc.

12th and 11th pins of MAX232 are connected to the 10th and 11th pins ofP89C51RD2FN controller respectively. These acts as a transmitter and receiver forthe data flow.


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To connect the MAX232 to the PC host we require a medium named as DB9connector. The 2nd and 3rd pin of the DB9 connector should be connected to the 14 thand 13th pins of MAX232 respectively. While the 5th pin is grounded.

The GSM module is connected to the controller through the connections between theDB9 connectors already mounted on the controller and GSM modules.

CHAPTER - 5


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CHAPTER-5

SOFTWARE IMPLEMENTATION

This chapter explores some real world applications of theP89V51RD2xx, and also includes how to interface the P89V51RD2xx to devicessuch as an LCD and a keyboard and its software functionality using embedded Clanguage.

5.1 JHD204A LCD INTERFACING

5.1.1Initializing the LCDBefore you using the LCD, the program must initialize and configure it. This is

accomplished by sending a number of initialization instructions to the LCD.The first instruction to send is the no of data for the LCD i.e., with an 8-bit or 4-bit

data bus. The other thing need to specify is display matrix; in the selected LCD it is a 5x8dot character font. These two options are selected by sending the command 38h to the LCDas a command. The command can give to the LCD by invoking the pre defined function calllcd_command with passing parameters value of 38H, the syntax for the same can be givenlike lcd_command (0x38).

5.1.2 The initialization sequence code can be given as follows:

lcd_command (0x38); // 2 lines and 5x7 matrixlcd_command (0x0E); // display on, cursor blinkinglcd_command (0x01); //clear display screenlcd_command (0x06); // increment cursor (shift cursor right)lcd_command (0x80); // force cursor to begging of 1st linelcd_command (0xC0); // force cursor to begging of 2nd linelcd_command (0x94); // force cursor to begging of 3rd linelcd_command (0xD4); // force cursor to begging of 4th line

5.1.3 Displaying the data into the LCD

void lcd_data(unsigned char value){

chdata=value;rs=1;rw=0;en=1;delay(150);en=0;

}


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5.1.4 Writing the commands to the LCD

void lcd_command(unsigned char value){

chdata=value;rs=0;rw=0;en=1;delay(100);en=0;

}

5.1.5 Reading data to LCD

void string(unsigned char *disp){

int x;for(x=0;disp[x]!=0;x++)

{lcd_data(disp[x]);

}}void nextline(unsigned char v){

if(v==1){lcd_command(0XC0);

}}void nextline1(unsigned char v){

if(v==21){

lcd_command(0X94);}

}void nextline2(unsigned char v){

if(v==41){

lcd_command(0XD4);}

}


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CHAPTER6


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CHAPTER - 6

APPLICATION, ADVANTAGES AND FUTURE SCOPE

6.1 Advantages:

A lot of interaction and information sharing occurs. No printing & photocopying costs. No manual effort. Helps to retain and develop the knowledge base of your college or office. Saves Time, Energy and finally Environment.

Saves from cutting of trees and becomes eco friendly.

6.2 Applications:

The applications of SMS based wireless display system in various fields includes

Educational institutions. Railways. Stock marketing. Internal information. Bus stations.

Menu information. Advertising. Public information

6.3 Future enhancement:

The use of microcontroller in place of a general purpose computer allows us totheorize on many further improvements on this project prototype. Temperature display during

periods wherein no message buffers are empty is one such theoretical improvement that isvery possible. The ideal state of the microcontroller is when the indices or storage space in

the SIM memory are empty and no new message is there to display. With proper use ofinterrupt routines the incoming message acts as an interrupt, temperature display is halted andthe control flow jumps over to the specific interrupt service routine which first validates thesenders number and then displays the information field. Another very interesting andsignificant improvement would be to accommodate multiple receiver MODEMS at thedifferent positions in a geographical area carrying duplicate SIM cards. With the help of

principles of TDMA technique, we can choose to simulcast and /or broadcast importantnotifications. After a display board receives the valid message through the MODEM anddisplays it, it withdraws its identification from the network &synchronously another nearbyMODEM signs itself into the network and starts to receive the message. The message is

broadcast by the mobile switching center for a continuous time period during which as many


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possible display board MODEMS catch the message and display it as per the constraint ofvalidation.

Multilingual display can be another added variation of the project. The display boardsare one of the single most important media for information transfer to the maximum number

of end users. This feature can be added by programming the microcontroller to use differentencoding decoding schemes in different areas as per the local language. This will ensure theincrease in the number of informed users. Graphical display can also be considered as a longterm but achievable and target able output. MMStechnology along with relatively high end microcontrollers to carry on the tasks of graphicsencoding and decoding along with a more expansive bank of usable memory can make thistask a walk in the park


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CHAPTER - 7


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Chapter7

DEBUGGING TECHNIQUES

7.1 Keil uvision Debugger

7.1.1 Introduction to Keil IDE

Keil is a compiler that has 3 windows, project window, edit window, andbuild or command window Schematic. Today, Keil Software provides a broad range ofdevelopment tools for the embedded systems marketplace. Their products include ANSICcompilers, macro assemblers, debuggers, linkers, library managers, and real-time operatingsystems.

. It was then that Keil Software implemented the first C compiler designed from theground-up specifically for the 89C51 microcontroller.

7.1.2 Features

1. Nine basic data types, including 32-bit IEEE floating-point2. Flexible variable allocation with bit, data, bdata, idata, xdata, and pdata memory

types3. Interrupt functions may be written in C4. Full use of the 8051 register banks5. Complete symbol and type information for source-level debugging6. Bit-addressable data objects7. Built-in interface for the RTX51 real-time kernel8. Support for dual data pointers on Atmel, AMD, Cypress, Dallas semiconductor,

Infineon, Philips, and Transcend microcontrollers9. Support for Phillips 8xC510,8xC71,and 8xC752 limited instruction sets10.Support for the Phillips 80C51 arithmetic unit.

The Keil 8051 Development Tools are designed to solve the complex problems facingembedded software developers.

When starting a new project, simply select the microcontroller you use from the DeviceDatabase and the vision IDE sets all compiler, assembler, linker, and memory optionsfor you.

Numerous example programs are included to help you get started with most popularembedded 8051 devices.

The Keil Vision Debugger accurately simulates on-chip peripherals (CAN, UART,SPI, Interrupts, I/O Ports, A/D Convertor, D/A convertor, and PWM Modules) of your8051 device. Simulation helps you understand hardware configurations and avoids time


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wasted on setup problems. Additionally, with simulation, you can write and testapplications before target hardware is available.

When you are ready to begin testing your software application with target hardware, usethe MON51, MONADI, or FlashMON51 Target Monitors, the ISD51 In-systemDebugger, or the ULINK USB-JTAG Adapter to download and test program code on

your target system.

7.1.3 Steps to follow while writing a program in keil:

1. Install Keil Micro Vision in your PC, Then after Click on that Keil UVision icon.After opening the window go to toolbar and select Project Tab then close previous project.

2. Next select New Project from Project Tab.

3. Then it will open Create New Project window. Select the path where you want to save

project and edit project name.

4. Next it opens Select Device for Target window, it shows list of companies and here youcan select the device manufacturer company.

5. For an example, for your project purpose you can select the chip as 89c51rd2xx fromPhilips Group. Next Click OK Button, it appears empty window here you can observe leftside a small window i.e., Project Window. Next create a new file.

6. From the Main tool bar Menu select File Tab and go to New, then it will open awindow, there you can edit the program.

7. Here you can edit the program as which language will you prefer either Assembly or C.

8. After editing the program save the file with extension as .c or .asm, if you write aprogram in Assembly Language save as .asm or if you write a program in C Languagesave as .c in the selected path.

9. Then after saving the file, compile the program. For compilation go to project windowselect source group and right click on that and go to Add files to Group.

10. Here it will ask which file has to add. For an example here you can add test.c as yousaved before

11. After adding the file, again go to Project Window and right click on your c file thenselect Build target for compilation. If there is any Errors orWarnings in your programyou can check in Output Window that is shown bottom of the Keil window.

12. Here in this step you can observe the output window for errors and warnings

13. If you make any mistake in your program you can check in this slide for which error andwhere the error is by clicking on that error

14. After compilation then next go to Debug Session. In Tool Bar menu go to Debug taband select Start/Stop Debug Session.

15. Write a program for Leds Blinking. LEDS are connected to PORT -1. you can observethe output in that port.


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16. To see the Ports and other Peripheral Features go to main toolbar menu and selectperipherals.

17. In this slide see the selected port i.e., PORT-1.

18. Start to trace the program in sequence manner i.e, step by step execution and observe theoutput in port window

19. After completion of Debug Session Create an Hex file for Burning the Processor. Here tocreate a Hex file goes to project window and right click on Target next select Option forTarget.

20. It appears one window; here in target tab modify the crystal frequency as youconnected to your microcontroller.

21. Next go to Output tab. In that Output tab click on Create HEX File and then clickOK.

22. Finally Once again compile your program. The Created Hex File will appear in your pathfolder

7.2 Flash magic

Flash Magic is a PC tool for programming flash based microcontrollers from NXPusing a serial or Ethernet protocol while in the target hardware.

7.2.1 Features

Straightforward and intuitive user interface Read any section of Flash and save as an Intel Hex file. Program security bits Automatic verifying after programming Five simple steps to erasing and programming a device and setting key options Fills unused Flash to increase firmware security Check which Flash blocks are blank or in use with the ability to easily erase all blocks

in use

Reprogram the Boot Vector and Status Byte with the help of confirmation featuresthat prevent accidentally programming incorrect values.

Display the contents of Flash in ASCII and Hexadecimal formats Single-click access to the manual, Flash Magic home page and NXP Microcontrollers

home page

Use high-speed serial communications on devices that support it.


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Command Line interface allowing use in IDEs and Batch Files. Supports half-duplex communications for many devices Verify Hex Files previously programmed Control the DTR and RTS RS232 signals to place the device into Boot ROM and

Execute modes automatically (requires hardware support)

Send commands to place the device in Boot loader mode Powerful, flexible Just In Time Code feature. Write your own JIT Modules to

generate last minute code for programming, for example serial number generation.

Displays information about the selected Hex File, including the creation andmodification dates, flash memory used, percentage of the current device used

Read the device signature Build your own Flash Magic based applications using the DLLs for C, C++, Python Build your own Flash Magic based applications using .NET languages (Windows

only)

7.3 Null MODEM checking (Hyper Terminal)

Debugging of 8051 application can be very easy if we able to send debug informationto serial port of PC. And its output can be seen on HyperTerminal (in Windows ) or Minicom

( in Linux ). We can display content of any variable, memory location etc. We can also printother useful information on serial terminal which could replicate the flow of the code.

The Microsoft HyperTerminal terminal emulation application can display messagessent from the serial port of a SDB or hardware platform. You can use these messages toverify whether the boot loader is on the SDB, to discover problems that may occur when theSDB boots, and to obtain the name of the SDB for use in the Platform Builder integrateddevelopment environment (IDE).

To configure HyperTerminal for BSPs

1. From the Windows Start menu, choose AllPrograms, and then choose Accessories.2. Choose Communications, and then choose HyperTerminal.3. In the Connection Description dialog box, in the Name box, type a name for the

connection to your SDB.4. From the Icon list, choose an icon to represent your connection, and then choose OK.5. In the Connect To dialog box, in the Connect using box, choose the communications

(COM) port on the development workstation through which you want to receivemessages from the SDB.The COM port that you choose must be the COM port on the development

workstation to which you attach the null modem cable.6. Choose OK.


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7. In the COM Properties dialog box, modify the settings for yourconnection so that the settings are correct for your BSP.

7.4 Hardware debugging techniques

In the context of hardware debugging techniques, we are going to observe thedifferent types of error and checking of the components in the project.

While considering the microcontroller, the voltage level at 30th pin must be 1.6Vbecause of the following reason

1. The voltage supply to the kit or mainly processor is 5V.2. The duty cycle of the microcontroller is 33%

Duty Cycle = T on / (T on+T off)

Where T off = 2* T onDC = 1/ (1+2)DC= 0.333

Hence the voltage at 30th pin should be product of Duty Cycle and voltage supplyVCC. Therefore the voltage should be 1.6V.

3. The voltage levels at 2nd and 6th pins of MAX232 should be -10V and +10Vrespectively.

CONCLUSION

RESULTS

Now the most awaited part of the program is final result which can be seen by the

following steps once the kit is ready.

Give 5V Power supply and to both controller and GSM module. Now ON the circuit. We can see on the LCD display NOTICE BOARD. Send an SMS using mobile that starts with a and ends with $ i.e... a -------- $. After receiving the SMS to the GSM module then the LCD displaysCOMMAND

SIGNAL RECEIVED.

After a delay, the content of the SMS is displayed on to the LCD.


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8. BIBILOGRAPHY:

Janci Gillespie Mazidi, Muhammad Ali Mazidi,The 8051micro controller andembedded systems, PHI Prentice hall India, Eastern Economy Edition,www.phindia.com.

Kenneth J. Ayala, The 8051 Microcontroller, architecture, Programming andApplications, Pen ram international publishing Pvt. Ltd. 1996

Arnold S. Berger, Embedded systems design, an introduction to process, tools, andTechniques, CMP Books, 2005. www.cmpbooks.com

Yashvant Kanetkar, Let Us C, BPB Publications, 1999www.bpbpub.com Dreamtech Software Team, Programming for Embedded systems, WILEY Publishing,

Inc, 2003.

http://en.wikipedia.org/wiki/Levels http://www.google.co.in
http://www.phindia.com/http://www.phindia.com/http://www.phindia.com/http://www.bpbpub.com/http://www.bpbpub.com/http://www.bpbpub.com/http://en.wikipedia.org/wiki/Levelshttp://en.wikipedia.org/wiki/Levelshttp://www.google.co.in/http://www.google.co.in/http://www.google.co.in/http://en.wikipedia.org/wiki/Levelshttp://www.bpbpub.com/http://www.phindia.com/


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APPENDICES

KEIL MICRO VISION IDE

Keil is a compiler that has 3 windows, project window, edit window, and build or commandwindow Schematic. Today, Keil Software provides a broad range of development tools forthe embedded systems marketplace. Their products include ANSIC compilers, macroassemblers, debuggers, linkers, library man

14092013094858 sms based notice board project

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