GSM based security system

Table of contents

Executive Summary ............................................................................................................. 2

Introduction ........................................................................................................................ 3

Part one .............................................................................................................................. 5

Hardware ............................................................................................................................ 5

Infrared Transmitter ....................................................................................................... 5

Infrared receiver ............................................................................................................. 6

Inverter gate (SN54/74LS04) .......................................................................................... 7

Microcontroller ............................................................................................................... 7

A Brief Introduction to 8051 Microcontroller ............................................................. 7

Pin Description of the AT89C55WD microcontroller: ............................................... 10

Interrupt .................................................................................................................... 12

Level-triggered interrupts ..................................................................................... 12

Enabling and disabling an interrupt .................................................................. 13

Serial Interrupt ...................................................................................................... 14

Serial data cable ............................................................................................................ 17

An Introduction to Nokia F-Bus ................................................................................ 18

The difference between F (Fast) bus and M (master) bus .................................... 18

Introduction to serial data cable (DB-9) ................................................................... 18

AT command supporting GSM mobile phone. ............................................................. 20

The phone we used for the project is an AT command supporting. At commands will

be explained in later topics later .................................................................................. 20

Part two ............................................................................................................................ 21

Software ........................................................................................................................... 21

Theory of Operation...................................................................................................... 21

Assembly Language ....................................................................................................... 23

Advantages of Assembly language .......................................................................... 23

ASM (assembly) form........................................................................................... 25

HEX (the program in hexadecimal values) form .................................................. 25

LST (list) form ...................................................................................................... 27

AT-Command set overview ....................................................................................... 30

Table 3: AT command set ......................................................................................... 30

AT command formats ............................................................................................... 30

The text mode ....................................................................................................... 30

PDU (protocol data unit) mode ............................................................................ 31

Coding 7-bit data (septets) into octets .............................................................. 31

ASCII Character Chart with Decimal, Binary and Hexadecimal Conversions .... 31

Sending a message in the PDU mode ....................................................................... 33

Serial Communication ................................................................................................... 35

Setting the Serial Port Mode ..................................................................................... 36

Setting the Baud rate ................................................................................................ 37

Application and future development ............................................................................... 38

Conclusion ......................................................................................................................... 39

Recommendation .............................................................................................................. 40

Reference materials .......................................................................................................... 41

Executive Summary

In today’s world, where the issue of security is of paramount importance, people,

institutions, government and non-government offices are concerned about it. And also

the field is growing with a very high pace.

This project, GSM BASED HOME SECURITY SYSTEM, is a system which works by using

Infrared sensors, Microcontroller, mobile transmitter and receiver units to alarm the

user of the system up on the intrusion of any unauthorized person or material in any

application area by sending text SMS to the user.

The GSM (Global system for Mobile communication) network, which we use in our daily

life for mobile communications, is utilized for different purposes other than simple voice

call services. And Security is one of the areas where GSM technology applies.

To make the microcontroller send SMS and make voice calls, the project exploited the

F/M protocol which applies in every mobile phone that supports AT commands.

A more specific block diagram representation of the project would be given in the

following form.

Fig.1 block diagram representation of the project

Fig.2 practical view of the block

Diagram

AT89C55

WD

Microcont

roller

Serial

Interface

Transmitte

r mobile

unit

Receiver

mobile

unit

IR

Receiver

Inverter

Gate

IR

Transmitter

AT89C55

WD

Serial

Connec

tion

SMS

IR

Sensor PORT1

And in practical ways we can view the system as the following diagram.

Introduction

There is a growing interest in intelligent home network as a way to offer a comfortable,

convenient and safe environment for occupants. In order to enhance the occupants’

convenience and safety, home security system is indispensable in the field of intelligent

home network. The requirements of a home security system include low cost, low

power consumption, easy installation and rapid response to alarm incidents.

How to inform user in real time when alarm incidents occur has become a crucial

feature of home security system. This can be done via internet or GSM. GSM is more

convenient than internet. The main reason is that the GSM network has wide spread

coverage making the whole system available for almost all the time. Furthermore, GSM

network has high security infrastructure which makes sure that the information sent or

received cannot be monitored

The project is aimed at developing the security of Home against Intruders. In this case,

while you are out of your home and a place is intruded then the device sends SMS to

the emergency number provided to it.

The report consists of a background into the area of 8051 microcontroller and mobile

communication, how they are interfaced to each other and AT (Attention) command

sets used in communication.

The project can be effectively applied to the following areas:-

• Home security- to monitor intrusion

• In monitoring restricted area, military areas

• In monitoring cash lockers

Furthermore by changing the sensors, signal conditioning elements and by

applying some changes on the microcontroller program it can also be applied for

• Fire alarm

• Sound level monitoring

• Pressure, water level, humidity monitoring etc…

Such security and also microcontroller based projects has not been made

previously in our department, and hence the project is not a continuation or based on

previous works.

Part one

Hardware The following materials are the hard ware components employed for this project.

1. Infrared Transmitter

2. Infrared receiver

3. Inverter gate (SN54/74LS04)

4. AT89C55WD Microcontroller

5. Serial cable

6. AT command supporting GSM mobile phone.

Infrared Transmitter Infra-Red actually is normal light with a particular colour. Humans can't see this

colour because its wave length of 950nm is below the visible spectrum. That's one of the

reasons why IR is chosen for remote control purposes or for detecting intrusion in our

case.

The infrared transmitter (LED) usually is a battery powered component. It should

consume as little power as possible, and the IR signal should also be as strong as possible

to achieve an acceptable control distance. Preferably it should be shock proof as well.

The current through the LED (or LEDs) can vary from 100mA to well over 1A.

In order to get an acceptable control distance the LED currents have to be as high as

possible. A trade-off should be made between LED parameters, battery lifetime and

maximum control distance. LED currents can be that high because the pulses driving

the LEDs are very short. Average power dissipation of the LED should not exceed the

maximum value though. You should also see to it that the maximum peek current for

the LED is not exceeded. All these parameters can be found in the LED's data sheet.

A simple transistor circuit can be used to drive the LED. A

transistor with a suitable HFE (transistor current gain) and switching

speed should be selected for this purpose. The resistor values can

simply be calculated using Ohm's law. The nominal voltage drop over

an IR LED is approximately 1.1V.

R

R

The normal driver, described above, has one disadvantage. As

the battery voltage drops, the current through the LED will decrease

as well. This will result in a shorter control distance that can be

covered.

fig.3 I/R transmitters

An emitter follower circuit can avoid this. The 2 diodes in

series will limit the pulses on the base of the transistor to 1.2V. The base-emitter

voltage of the transistor subtracts 0.6V from that, resulting in constant amplitude of

0.6V at the emitter. This constant amplitude across a constant resistor results in

current pulses of a constant magnitude. Calculating the current through the LED is

simply applying Ohm's law again.

Infrared receiver

In the picture below we can see a typical block diagram of an IR receiver.

The received IR signal is picked up by the IR detection diode on the left side of the

diagram. This signal is amplified and limited by the first 2 stages. The limiter acts as

an AGC circuit to get a constant pulse level, regardless of the distance to the

transmitter.

Fig.4 I/R receiver

As we can see only the AC signal is sent to the Band Pass Filter. The Band Pass

Filter is tuned to the modulation frequency of the transmitter unit. Common

frequencies range from 30 KHz to 60 KHz in consumer electronics.

The next stages are a detector (demodulator), integrator and comparator. The

purpose of these three blocks is to detect the presence of the modulation frequency. If

this modulation frequency is present the output of the comparator will be pulled low.

All these blocks are integrated into a single electronic component. There are

many different manufacturers of these components on the market. And most devices

are available in several versions each of which are tuned to a particular modulation

frequency.

Fig.5 integrated

I/R receiver

Inverter gate (SN54/74LS04)

In digital logic, an inverter or NOT gate is a logic gate which implements logical

negation. The truth table is shown below

Fig.6: Typical inverter gate

In our case we used the SN54/74LS04 which is a group of 6 inverters found in an

IC form. The purpose of this inverter gate in our case is to invert the signal from the

receiver unit so that it changes the normally high state of the receiver (low state at the

output of the inverter) to high state, so that the intrusion (low state at the receiver) is

detected.

Fig. 7: SN54/74LS04 inverter gate

Microcontroller

A Brief Introduction to 8051 Microcontroller

When we have to learn about a new computer we have to familiarize about the

machine capability we are using, and we can do it by studying the internal hardware

design (devices architecture), and also to know about the size, number and the size of

the registers.

INPUT A

OUTPUT NOT A

0 1

1 0

Vcc

7 2 3 4 5 6 1

8 9 10 11 12 14 13

GND

Table 1: Truth

table for

Inverter Gate

A microcontroller is a single chip that contains the processor (the CPU), non-

volatile memory for the program (ROM or flash), volatile memory for input and output

(RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of

microcontroller units (MCUs) are embedded each year in a myriad of products from toys

to appliances to automobiles. For example, a single vehicle can use 70 or more

microcontrollers. The following picture describes a general block diagram of

microcontroller.

The following are some of the capabilities of 8051 microcontroller.

� Internal ROM and RAM

� I/O ports with programmable pins

� Timers and counters

� Serial data communication

The 8051 architecture consists of these specific features:

� 16 bit PC &data pointer (DPTR)

Fig.8: Block

diagram of

microcontroller

� 8 bit program status word (PSW)

� 8 bit stack pointer (SP)

� Internal ROM 4k

� Internal RAM of 128 bytes.

� 4 register banks, each containing 8 registers

� 80 bits of general purpose data memory

� 32 input/output pins arranged as four 8 bit ports: P0-P3

� Two 16 bit timer/counters: T0-T1

� Two external and three internal interrupt sources Oscillator

and clock circuits.

The microcontroller used in this project is Atmel’s AT89C55WD. The AT89C55WD is a

low-power; high-performance CMOS 8-bit microcomputer with 20K bytes of Flash

programmable read only memory and 256 bytes of RAM. The device is manufactured

using Atmel’s high-density nonvolatile memory technology and is compatible with the

industry standard 80C51 and 80C52 instruction set and pin out. The on-chip Flash allows

the program memory to be user programmed by a conventional nonvolatile memory

programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the

Atmel AT89C55WD is a powerful microcomputer which provides a highly flexible and

cost effective solution to many embedded control applications.

The AT89C55WD provides the following standard features:

• 20K bytes of flash, 256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a

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

oscillator, and clock circuitry.

• In addition, the AT89C55WD is designed with static logic for operation down to

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

Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port,

and interrupt system to continue functioning. The Power-down Mode saves the

RAM contents but freezes the oscillator, disabling all other chip functions until

the next external interrupt or hardware reset.

The pin diagram of the 8051 shows all of the input/output pins unique to

microcontrollers:

Pin Description of the AT89C55WD microcontroller:

• VCC: Supply voltage.

• GND: Ground.

• Port 0: Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port,

each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins

can be used as high impedance inputs. Port 0 may also be configured to be the

multiplexed low order address/data bus during accesses to external program and

data memory. In this mode P0 has internal pull-ups. Port 0 also receives the code

bytes during Flash programming, and outputs the code bytes during program

verification. External pull-ups are required during program verification

• Port 1: Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port

1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1

pins they are pulled high by the internal pull-ups and can be used as inputs. As

Fig. 9: 8051 family

microcontroller chip

inputs, Port 1 pins that are externally being pulled low will source current (IIL)

because of the internal pull-ups. Port 1 also receives the low-order address bytes

during Flash programming and verification.

• Port 2: Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port

2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2

pins they are pulled high by the internal pull-ups and can be used as inputs. As

inputs, Port 2 pins that are externally being pulled low will source current (IIL)

because of the internal pull-ups. Port 2 emits the high-order address byte during

fetches from external program memory and during accesses to external data

memory that uses 16-bit addresses (MOVX @ DPTR). In this application, it uses

strong internal pull-ups when emitting 1s. During accesses to external data

memory that uses 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the

P2 Special Function Register. Port 2 also receives the high-order address bits and

some control signals during Flash programming and verification.

• Port 3

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

can sink/source four TTL inputs. When 1s are written to Port 3 pins they are pulled high

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

externally being pulled low will source current because of the pull-ups. Port 3 also

serves the functions of various special features of the AT89C51 as listed below:

Table 2: pin description of port 3

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

P3.6 WR (external data memory write strobe)

P3.7 RD (external data memory read strobe)

Interrupt

As the name implies, an interrupt is some event which interrupts normal program

execution.

Program flow is always sequential, being altered only by those instructions which

expressly cause program flow to deviate in some way. However, interrupts give us a

mechanism to "put on hold" the normal program flow, execute a subroutine, and then

resume normal program flow as if we had never left it. This subroutine, called an

interrupt handler, is only executed when a certain event (interrupt) occurs. The event may

be one of the timers "overflowing," receiving a character via the serial port, transmitting a

character via the serial port, or one of two "external events."(INT0, INT1)

The 8051 may be configured so that when any of these events occur the main program is

temporarily suspended and control passed to a special section of code which presumably

would execute some function related to the event that occurred. Once complete, control

would be returned to the original program. The main program never even knows it was

interrupted.

The ability to interrupt normal program execution when certain events occur makes it

much easier and much more efficient to handle certain conditions. If it were not for

interrupts we would have to manually check in our main program whether the timers had

overblown, whether we had received another character via the serial port, or if some

external event had occurred.

Interrupts can be triggered externally in two ways.

Edge triggered and

Level triggered

Level-triggered interrupts

– INT0 and INT1 pins are normally high

– if low-level signal is applied, it triggers the interrupt

– microcontroller stops whatever it is doing and jumps to the interrupt

vector table to service the interrupt

– the low level signal must be removed before the execution of the last

instruction of the interrupt service routine, RETI

– otherwise, another interrupt will be generated

Edge triggered interrupt

is a class of interrupts that are signaled by a level transition on the interrupt line,

either a falling edge (1 to 0) or a rising edge (0 to 1). A device wishing to signal an

interrupt drives a pulse onto the line and then releases the line to its quiescent state. If

the pulse is too short to be detected by polled I/O then special hardware may be

required to detect the edge.

Enabling and disabling an interrupt

– upon reset all interrupts are disabled

– interrupts must be enabled by software

– IE register (interrupt enable) is responsible for enabling and disabling the

interrupts

– IE is a bit-addressable register

Steps in enabling an interrupt

– EA must be set to 1

– set the relevant bits in IE register to high

– EA = 0, no interrupt will be responded to, even if the relevant bit in the IE

register is high

In this project external interrupt 1 (INT1) is used. This interrupt is falling edge interrupt

(i.e. it is triggered when the input signal changes from logic 1 (HIGH) to logic 0 (LOW).)

For instance, the following program line shows how external interrupt 1 is enabled for

the falling edge trigger.

MOV IE, #84H ; ENABLE EXTERNAL INTERRUPT 1

84H is 10000100 in binary and loading 84H to the Interrupt enable (IE) register

84H 1 0 0 0 0 1 0 0

IE bits EA -- ET2 ES ET1 EX1 ET0 EX0

Serial Interrupt

Serial Interrupts are slightly different than the rest of the interrupts. This is due to the

fact that there are two interrupt flags: RI and TI. If either flag is set, a serial interrupt is

triggered. The RI bit is set when a byte is received by the serial port and the TI bit is set

when a byte has been sent.

This means that when your serial interrupt is executed, it may have been triggered

because the RI flag was set or because the TI flag was set--or because both flags were

set. Thus, your routine must check the status of these flags to determine what action is

appropriate. Also, since the 8051 does not automatically clear the RI and TI flags you

must clear these bits in your interrupt handler.

Example,

MOV SBUF, #’A’ ; Character A is sent through the serial interface

CLR Ti ; Clear the TI bit before we send another character

CHECK: JNB TI, CHECK ; if the TI flag is not set, we jump to the exit point

CLR TI; Clear the TI bit before we send another character

MOV SBUF, #’T’ ; Send another character to the serial port

• RST

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

resets the device.

• ALE/PROG

Address Latch Enable output pulse for latching the low byte of the address during

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

Flash Programming. In normal operation ALE is emitted at a constant rate of 1/6 the

oscillator frequency, and may be used for external timing or clocking purposes. Note,

however, that one ALE pulse is skipped during each access to external Data Memory. If

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

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

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

execution mode.

• PSEN

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

AT89C51 is executing code from external program memory, PSEN is activated twice each

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

external data memory.

• EA/VPP

External Access Enable (EA) must be strapped to GND in order to enable the device to

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

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

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

receives the 12-volt programming enable voltage (VPP) during Flash programming, for

parts that require 12-volt VPP.

• XTAL1

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

circuit.

• XTAL2

It is the output from the inverting oscillator amplifier. Unconnected while XTAL1 is

driven as shown in Figure 2. There are no requirements on the duty cycle of the external

clock signal, since the input to the internal clocking circuitry is through a divide-by-two

flip-flop, but minimum and maximum voltage high and low time specifications must be

observed.

• Idle Mode

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

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

functions registers remain unchanged during this mode. The idle mode can be

terminated by any enabled interrupt or by a hardware reset. It should be noted that

when idle is terminated by a hard ware reset, the device normally resumes program

execution, from where it left off, up to two machine cycles before

The internal reset algorithm takes control. On-chip hardware inhibits access to internal

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

possibility of an unexpected write to a port pin when Idle is terminated by reset, the

instruction following the one that invokes Idle should not be one that writes to a port

pin or to external memory.

Serial data cable

Is a data transfer cable to connect the phone with a PC and to a Microcontroller in our

case. There are many different types of such cables depending on their manufacturers,

architecture, protocols, number of pins, time of manufacturing. Some of these cables. . .

• Serial data cable

• USB data cable

• RJ-45 data cable

• POP port data cable

This project uses an F/M bus serial data cable. This data cable has one end an F/M bus

to connect to the mobile f/M pins and other end a serial to directly connect with the

microcontroller. We use this cable because the microcontrollers have no any other ports

than the serial port with nine pins (DB-9).

Fig 10: F/M bus serial data cable for Nokia 3310 fig.11: Nokia 3310

An Introduction to Nokia F-Bus

Most Nokia phones have F-Bus and M-Bus connections that can be used to connect

a phone to a PC or in our case a microcontroller. The connection can be used for

controlling just about all functions of the phone, as well as uploading new firmware etc.

This bus will allow us to send and receive SMS messages. The cable contains electronics

to level convert 3V signals (of the F/M bus) to RS232 (of the serial port) type signals.

There are also M and F bus switching in most cables.

The difference between F (Fast) bus and M (master) bus

M-Bus is a one pin bi-directional bus for both transmitting and receiving data from

the phone. It is slow (9600bps) and only half-duplex. Only two pins on the phone are

used. One ground and one data. M-Bus runs at 9600bps, 8 data bits, odd parity, and one

stop bit. The data terminal ready (DTR) pin must be cleared with the request to send

(RTS). This powers the electronics in the cable.

F-Bus is the later high-speed full-duplex bus. It uses one pin for transmitting data and

one pin for receiving data plus the ground pin. Very much like a standard serial port. It is

fast 115,200bps, 8 data bits, no parity, and one stop bit. For F-Bus the data terminal ready

(DTR) pin must be set and the request to send (RTS) pin cleared.

Introduction to serial data cable (DB-9)

In telecommunications, RS-232 (Recommended Standard 232) is a 9 pin standard for

serial binary single-ended data and control signals connecting between a DTE (Data

Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly

used in computer serial ports. In RS-232, user data is sent as a time-series of bits.

Fig.12:

F/M bus pins for Nokia 3310

(Under the back cover)

Both synchronous and asynchronous transmissions are supported by the standard. In

addition to the data circuits, the standard defines a number of control circuits used to

manage the connection between the DTE and DCE. Each data or control circuit only

operates in one direction, which is, signaling from a DTE to the attached DCE or the

reverse. Since transmit data and receive data are separate circuits, the interface can

operate in a full duplex manner, supporting concurrent data flow in both directions. The

standard does not define character framing within the data stream, or character encoding.

Synchronous serial transmission requires that the sender and receiver share a

clock with one another, or that the sender provide a strobe or other timing signal

so that the receiver knows when to “read” the next bit of the data.

Asynchronous transmission allows data to be transmitted without the sender

having to send a clock signal to the receiver. Instead, the sender and receiver must

agree on timing parameters in advance and special bits are added to each word

which are used to synchronize the sending and receiving units.

Fig. 13: DB-9 female connector

AT command supporting GSM mobile phone.

The phone we used for the project is an AT command supporting. At

commands will be explained in later topics later

Introduction to GSM network

GSM (Global System for Mobile Communications): is the most popular standard for

mobile telephony systems in the world. It is estimated that 80% of the global mobile

market uses the standard. Its ubiquity enables international roaming arrangements

between mobile phone operators, providing subscribers the use of their phones in many

parts of the world.

GSM differs from its predecessor technologies in that both signaling and speech

channels are digital, and thus GSM is considered a second generation (2G) mobile phone

system. This also facilitates the wide-spread implementation of data communication

applications into the system.

GSM also pioneered low-cost implementation of the short message service (SMS), also

called text messaging, which has since been supported on other mobile phone

standards as well.

The GSM network works in the spectral range of 900MHz-1800MHz. Our country also

uses this GSM network for mobile communication and to the benefit of the network we

use a GSM phone, found widely in the market too.

Part two

Software

Theory of Operation

In this project we interfaced the AT89C55WD microcontroller with Nokia GSM mobile

phone through an F/M bus serial data cable to send SMS message automatically upon

intrusion which is detected by the use of an infrared sensor as discussed above. The

protocol used for the communication between the microcontroller and the GSM phone

is called AT command.

When the interrupt fed to the microcontroller is triggered (i.e. when there is an intruder

in the house), the microcontroller sends a predefined AT commands for a predefined

mobile numbers.

Any microcontroller can be programmed using C language or assembly language

programming. In the project the assembly is applied because it uses very small memory

space and also more compact than other languages such as C.

Flow Chart of the microcontroller program to accomplish the required task is give below

and description about the assembly programming and AT command sets will follow.

Yes

Label

Check

interrupt

START

Select external interrupt as edge trigger

Select six cycle machine mode

Select baud rate of 115200 bps

Give the sms command to mobile for first number

Delay of 4 sec

Give the SMS command to mobile for the second number

Delay of 4 sec

Give dialing command to mobile for second number

Give dialing command to mobile for first number

Jump on label

Reset

Stop

NO

Fig. 14: flow diagram of the program

Assembly Language

Assembly languages are a type of low-level languages for programming computers,

microprocessors, microcontrollers, and other (usually) integrated circuits. They

implement a symbolic representation of the numeric machine codes and other

constants needed to program a particular CPU architecture. This representation is

usually defined by the hardware manufacturer, and is based on abbreviations (called

mnemonics) that help the programmer remember individual instructions, registers, etc.

An assembly language family is thus specific to certain physical (or virtual) computer

architecture. This is in contrast to most high-level languages, which are (ideally)

portable.

A utility program called an assembler is used to translate assembly language statements

into the target computer's machine code. The assembler performs a more or less

isomorphic translation (a one-to-one mapping) from mnemonic statements into

machine instructions and data. This is in contrast with high-level languages, in which a

single statement generally results in many machine instructions.

Many sophisticated assemblers offer additional mechanisms to facilitate program

development, control the assembly process, and aid debugging. In particular, most

modern assemblers include a macro facility (described below), and are called macro

assemblers.

Advantages of Assembly language

It is possible to program a microcontroller by using either assembly language or C

programming language. We chose assembly language because of the following reasons.

• Assembly language is compact (i.e. it takes small memory space compared to C)

• Assembly code has fine control that it allows over the code.

An advantage of assembly language over high level languages is the fine control that it

allows over the code. Since assembly language directly correlates which machine

instructions, the only way to get closer to the machine is to write in binary or hex code.

Another advantage is that you can invoke specialized instructions to do I/O, or

manipulate hardware, such as page descriptor tables in the kernel.

The fine control advantage is, however, illusive. Modern compilers do a very good job of

optimizing, and assembly language is very verbose, requiring you to specify

"everything", and to keep track of "everything".

The project uses an assembler environment called MIDE-51 studio. The snap shot and

some explanation is given below of the assembler.

Features of the MIDE-51 studio:

• Syntax highlighter on ASEM-51 reserved word & addition register on selected

device (devices listed on ASEM51/MCU folder)

• Support standard editor feature and shortcut key such as Cut , Copy, Paste, Find,

Replace and Windows tile & cascade

• Save recent file(s) opened in list

• Report assembler & compiler message

The MIDE-51 studio saves the microcontroller program we written on it is three different

formats. ASM (assembly) form, HEX (the program in hexadecimal values) form, and the

LST (list) file formats.

Fig. 15: snapshot

Of MIDE-51

studio

ASM (assembly) form

Program written in assembly language, a low level programming language that can be

converted to machine language; may be edited with a text editor and run using an

assembler program, such as MIDE-51 studio.This format is the type we call the source

code for the microcontroller.

Example of .ASM file

ORG 807FH

HERE1: MOV PCON, #80H; TO SET SMOD BIT FOR DOUBLE BAUD RATE

MOV TMOD, #20H; TIMER 1 MODE 2 (AUTORELOAD)

MOV TH1, #0FFH; 115200 BAUD RATE

MOV SCON, #40H; 8 BIT, 1 STOP BIT

SETB TR1 ; START TIMER 1

CLR TI

MOV SBUF, #’A’; COMMAND

AAAA: JNB TI, AAAA

CLR TI

MOV SBUF,’#'

HEX (the program in hexadecimal values) form

The format is a text file, with each line containing hexadecimal values encoding a

sequence of data and their starting offset or absolute address.

There are three types of HEX: 8-bit, 16-bit, and 32-bit. They are distinguished by their

byte order.

Each line of HEX file consists of six parts:

1. Start code, one character, an ASCII colon ':'.

2. Byte count, two hex digits, a number of bytes (hex digit pairs) in the data field.

16 (0x10) or 32 (0x20) bytes of data are the usual compromise values between

line length and address overhead.

3. Address, four hex digits, a 16-bit address of the beginning of the memory

position for the data. Limited to 64 kilobytes, the limit is worked around by

specifying higher bits via additional record types.

4. Record type, two hex digits, 00 to 05, defining the type of the data field.

5. Data, a sequence of n bytes of the data themselves, represented by 2n hex digits.

6. Checksum, two hex digits - the least significant byte of the two's complement of

the sum of the values of all fields except fields 1 and 6 (Start code ":" byte and

two hex digits of the Checksum).

Example of .HEX file

Following is a typical Hex-record module consisting of four data records and a

termination record.

: 10010000214601360121470136007EFE09D2190140

: 100110002146017EB7C20001FF5F16002148011988

: 10012000194E79234623965778239EDA3F01B2CAA7

: 100130003F0156702B5E712B722B732146013421C7

: 00000001FF

The first data record is explained as follows:

: Start code.

10 Hex 10 (decimal 16), indicating 16 data character

pairs, 16 bytes of binary data, in this record.

01 Four-character 2-byte address field: hex address 0100,

00 indicates location where the following data is to be loaded.

00 Record types indicating a data record.

The next 16 character pairs are the ASCII bytes of the actual program

data.

40 Checksum of the first Hex-record.

The termination record is explained as follows:

: Start code.

00 Byte count is zero, no data in termination record.

00 Four-character 2-byte address fields, zeros.

00

01 Record type 01 is termination.

FF Checksum of termination record.

LST (list) form

Is the machine language equivalent of the .ASM file formats. In this case each of the

.ASM commands has their respective representation on the machine code, the .LST

representation.

Below is the .LST equivalent for the section of source code we wrote above.

16: N 807F ORG 807FH

17: 807F 75 87 80 HERE1: MOV PCON,#80H ;TO SET SMOD BIT FOR DOUBLE BAUD RATE

18: 8082 75 89 20 MOV TMOD,#20H ;TIMER 1 MODE 2 (AUTORELOAD)

19: 8085 75 8D FF MOV TH1,#0FFH ;115200 BAUD RATE

20: 8088 75 98 40 MOV SCON,#40H ;8 BIT,1 STOP BIT

21: 808B D2 8E SETB TR1 ;START TIMER 1

22: 808D C2 99 CLR TI

23: 808F 75 99 41 MOV SBUF,#'A' ;COMMAND

24: 8092 30 99 FD AAAA: JNB TI,AAAA

25: 8095 C2 99 CLR TI

26: 8097 75 99 54 MOV SBUF,#'T'

AT-Command set

AT commands are instructions used to control a modem. AT is the abbreviation of

Attention. Every command line starts with "AT" or "at". That's why modem commands

are called AT commands. Many of the commands that are used to control wired dial-up

modems, such as ATD (Dial), ATA (Answer), ATH (Hook control) and ATO (Return to

online data state), are also supported by GSM modems and mobile phones. Besides this

List form Source code

common AT command set, GSM modems and mobile phones support an AT command

set that is specific to the GSM technology, which includes SMS-related commands like

AT+CMGS (Send SMS message), AT+CMSS (Send SMS message from storage), AT+CMGL

(List SMS messages) and AT+CMGR (Read SMS messages).

Note that the starting "AT" is the prefix that informs the modem about the start of a

command line. It is not part of the AT command name. For example, D is the actual AT

command name in ATD and +CMGS is the actual AT command name in AT+CMGS.

However, some books and web sites use them interchangeably as the name of an AT

command.

Here are some of the tasks that can be done using AT commands with a GSM modem or

mobile phone:

• Get basic information about the mobile phone or GSM/GPRS modem. For

example, name of manufacturer (AT+CGMI), model number (AT+CGMM), IMEI

number (International Mobile Equipment Identity) (AT+CGSN) and software

version (AT+CGMR).

• Get basic information about the subscriber. For example, MSISDN (AT+CNUM)

and IMSI number (International Mobile Subscriber Identity) (AT+CIMI).

• Get the current status of the mobile phone or GSM/GPRS modem. For example,

mobile phone activity status (AT+CPAS), mobile network registration status

(AT+CREG), radio signal strength (AT+CSQ), battery charge level and battery

charging status (AT+CBC).

• Establish a data connection or voice connection to a remote modem (ATD, ATA,

etc).

• Send and receive fax (ATD, ATA, AT+F*).

• Send (AT+CMGS, AT+CMSS), read (AT+CMGR, AT+CMGL), write (AT+CMGW) or

delete (AT+CMGD) SMS messages and obtain notifications of newly received

SMS messages (AT+CNMI).

• Read (AT+CPBR), write (AT+CPBW) or search (AT+CPBF) phonebook entries.

• Perform security-related tasks, such as opening or closing facility locks

(AT+CLCK), checking whether a facility is locked (AT+CLCK) and changing

passwords (AT+CPWD).

(Facility lock examples: SIM lock [a password must be given to the SIM card

every time the mobile phone is switched on] and PH-SIM lock [a certain SIM card

is associated with the mobile phone. To use other SIM cards with the mobile

phone, a password must be entered.])

• Control the presentation of result codes / error messages of AT commands. For

example, you can control whether to enable certain error messages (AT+CMEE)

and whether error messages should be displayed in numeric format or verbose

format (AT+CMEE=1 or AT+CMEE=2).

• Get or change the configurations of the mobile phone or GSM/GPRS modem. For

example, change the GSM network (AT+COPS), bearer service type (AT+CBST),

radio link protocol parameters (AT+CRLP), SMS center address (AT+CSCA) and

storage of SMS messages (AT+CPMS).

• Save and restore configurations of the mobile phone or GSM modem. For

example, save (AT+CSAS) and restore (AT+CRES) settings related to SMS

messaging such as the SMS center address.

Note that mobile phone manufacturers usually do not implement all AT commands,

command parameters and parameter values in their mobile phones. Also, the behavior

of the implemented AT commands may be different from that defined in the standard.

In general, GSM modems designed for wireless applications have better support of AT

commands than ordinary mobile phones.

In addition, some AT commands require the support of mobile network operators. For

example, SMS over GPRS can be enabled on some GPRS mobile phones and GPRS

modems with the +CGSMS command (command name in text: Select Service for MO

SMS Messages). But if the mobile network operator does not support the transmission

of SMS over GPRS, you cannot use this feature.

The commands can be tried out by connecting a GSM modem to one of the PC’s COM

ports. Type in the test-command, adding CR + LF (Carriage return + Line feed = \r\n)

before executing. Table gives an overview of the implemented AT-Commands in this

application. The use of the commands is described in the later sections.

AT-Command set overview

Table 3: AT command set AT command formats

There are two ways of sending and receiving SMS messages by using a PC or

microcontroller.

• Text mode and

• PDU (protocol description unit) mode.

The text mode

(unavailable on some phones) is just an encoding of the bit stream represented by the

PDU mode. This mode simply uses the above explained AT commands directly to send

SMS and for dialing. Alphabets may differ and there are several encoding alternatives

when displaying an SMS message. The most common options are "PCCP437", "PCDN",

"8859-1", "IRA" and "GSM". These are all set by the at-command AT+CSCS, when you

read the message in a computer application. If you read the message on your phone,

the phone will choose a proper encoding. An application capable of reading incoming

SMS messages can thus use text mode or PDU mode. If text mode is used, the

application is bound to (or limited by) the set of preset encoding options. In some cases,

that's just not good enough. If PDU mode is used, any encoding can be implemented.

When selecting from text mode and PDU mode AT+CMGF=1 will select us the TEXT

mode and AT+CMGF=0 will select us the PDU mode.

E.g.

• ATI Returns general modem identification

Command Description

AT

Check if serial interface and GSM modem is

working.

ATE0 Turn echo off, less traffic on serial line.

AT+CNMI Display of new incoming SMS.

AT+CPMS Selection of SMS memory.

AT+CMGF SMS string format, how they are compressed.

AT+CMGR

Read new message from a given memory

location.

AT+CMGS Send message to a given recipient.

AT+CMGD Delete message.

• ATD<phone number> Dials the phone number you supplied (don’t enter the <>

brackets)

• ATH Hang-up the phone (useful after the previous command).

PDU (protocol data unit) mode

The formatting of these PDU’s is a little more complicated and requires some bit

manipulations that are hard to do by hand.

The GSM modem is put into PDU mode with the command ‘AT+CMGF=0’. Once in

PDU mode a PDU can be sent using the ‘AT+CMGS’ command:

AT+CMGS=<length><CR>

> <here goes your PDU><Crtl-Z>

The actual PDU consists of a number of octets (bytes). In the command the <length>

field represents the number of octets and the PDU is given in the hexadecimal

representation of those octets. The ‘> ‘on the second line is a prompt that is written by the

GSM modem to indicate that it is ready to accept the PDU.

Coding 7-bit data (septets) into octets

The message "hello GSM" consists of 10 characters, called septets when represented by

7 bits each. These septets need to be transformed into octets for the SMS transfer.

Table 4: coding 7 bit data into octates

ASCII Character Chart with Decimal, Binary and Hexadecimal Conversions

text h e l l o Space G S M

Deci. 104 101 108 108 111 32 71 83 77

7.bit

binary(septate) 1101000 1100101 1101100 1101100 1101111 0100000 1000111 1010011 1001101

7.bit

binary(septate) 1101000

110010 1

11011 00

1101 100

110 1111

0100000 1 000111

1010011

1001101

octate 1 1101000

00 110010

100 11011

1111 1101

00000 110

000111 01

1010011 1

1001101

Hex. E8 32 9B FD 06 1D A7

4D

ASCII stands for "American Standard Code for Information Interchange". It is the

character set that is used in PCs and most other small computers. The table below lists all

of the alphanumeric characters in the character set, along with their decimal, 7 bit

septet(7 bit binary) and hexadecimal number equivalents, so you can also use it as a

conversion chart:

Instead of using the above time taking and boring method It’s also possible to use an

application to change the 7-bit data (septets) into octets. This application which can be

downloaded easily from the internet is called SMS packer.

Table5: ASCII HEX Binary conversion chart

By using this application we can easily convert any message type in to its hexadecimal

equivalent.

Sending a message in the PDU mode

The following example shows how to send the message "hello GSM" in the PDU mode

from a Cell phone.

AT+CMGF=0 //Set PDU mode

AT+CSMS=0 //Check if modem supports SMS commands

AT+CMGS=21 //Send message, 21 octets (excluding the two initial zeros)

>0011000A8190212000120000AA08E8329BFD061DA74D <ctrl-z>

There are 23 octets in this message (46 'characters'). The first octet ("00") doesn't count,

it is only an indicator of the length of the SMSC information supplied (0). The PDU string

consists of the following:

Fig. 16: snap shot of SMS packer

Octet(s) Description

00

Length of SMSC information. Here the length is 0, which means

that the SMSC stored in the phone should be used. Note: This

octet is optional. On some phones this octet should be omitted!

(Using the SMSC stored in phone is thus implicit)

11 First octet of the SMS-SUBMIT message.

00 TP-Message-Reference. The "00" value here lets the phone set

the message reference number itself.

0A Address-Length. Length of phone number (10)

81

Type-of-Address. (81 indicates unknown phone format of the

phone number). This is used when the user or network has no a

priori information about the numbering plan. In this case, the

Address-Value field is organized according to the network

dialing plan.

9021200012

The phone number in semi octets (0912020021). The length of

the phone number is even (10), therefore a trailing F is not

added.

00 TP-PID. Protocol identifier

00

TP-DCS. Data coding scheme. This message is coded according to

the 7bit default alphabet. Having "04" instead of "00" here,

would indicate that the TP-User-Data field of this message

should be interpreted as 8bit rather than 7bit (used in e.g. smart

messaging, OTA provisioning etc).

AA TP-Validity-Period. "AA" means 4 days. Note: This octet is

optional, see bits 4 and 3 of the first octet

08

TP-User-Data-Length. Length of message. The TP-DCS field

indicated 7-bit data, so the length here is the number of septets

(8). If the TP-DCS field were set to 8-bit data or Unicode, the

length would be the number of octets.

E8329BFD061DA74D TP-User-Data. These octets represent the message "hello GSM".

Table 6: parts of the PDU string

Serial Communication

Serial communication is often used either to control or to receive data from an embedded

microprocessor.

In serial communication the bits are transmitted at specific time intervals determined by

the baud rate of the serial signal. Each byte is preceded by a start bit and followed by

one stop bit as shown in the figure below. The start and stop bits are used to

synchronize the serial receivers. The data byte is always transmitted least-significant-bit

first. For error checking it is possible to include a parity bit as well, just prior to the stop

bit.

Fig.17: Serial Waveform

One of the 8051’s many powerful features is its integrated UART, otherwise known as a

serial port. The fact that the 8051 has an integrated serial port means that you may very

easily read and write values to the serial port. If it were not for the integrated serial port,

writing a byte to a serial line would be a rather tedious process requiring turning on and

off one of the I/O lines in rapid succession to properly "clock out" each individual bit,

including start bits, stop bits, and parity bits.

However, we do not have to do this. Instead, we simply need to configure:

• The serial ports operation mode and

• Baud rate

Once configured, all we have to do is write to an SFR (special function register) to write

a value to the serial port or read the same SFR to read a value from the serial port. The

8051 will automatically let us know when it has finished sending the character we wrote

and will also let us know whenever it has received a byte so that we can process it. We do

not have to worry about transmission at the bit level--which saves us quite a bit of coding

and processing time.

Setting the Serial Port Mode

First, let’s present the "Serial Control" (SCON) SFR and define what each bit of the SFR

represents:

Bit Name Bit

Address Explanation of Function

7 SM0 9Fh Serial port mode bit 0

6 SM1 9Eh Serial port mode bit 1.

5 SM2 9Dh Multiprocessor Communications Enable (explained later)

4 REN 9Ch Receiver Enable. This bit must be set in order to receive

characters.

3 TB8 9Bh Transmit bit 8. The 9th bit to transmit in mode 2 and 3.

2 RB8 9Ah Receive bit 8. The 9th bit received in mode 2 and 3.

1 TI 99h Transmit Flag. Set when a byte has been completely

transmitted.

0 RI 98h Receive Flag. Set when a byte has been completely received.

Additionally, it is necessary to define the function of SM0 and SM1 by an additional

table:

Table 7: bit description of SCON

Note: The baud rate indicated in this table is doubled if PCON.7 (SMOD) is set.

In the program, for sending the AT command to the serial port the program line used is:-


The Special function register SCON (serial control) is loaded with #40H which has

binary equivalent of 01000000.

40H 0 1 0 0 0 0 0 0

SCON bits SM0 SM1 SM2 REN TB8 RB8 TI RI

The combination of SM0 and SM1 for 40H is 0, 1 which is defined as 8-bit UART and

baud rate set by timer 1 (*) in the additional table above.

Setting the Baud rate

The baud rate is the reciprocal of the time to send 1 bit. Error-free serial communication

requires that the baud rate, number of data bits, number of stop bits, and presence or

absence of a parity bit be the same at the transmitter and at the receiver.

In mode 1, the baud rate is determined by how frequently timer 1 overflows. The more

frequently timer 1 overflows, the higher the baud rate. There are many ways one can

cause timer 1 to overflow at a rate that determines a baud rate, but the most common

method is to put timer 1 in 8-bit auto-reload mode (timer mode 2) and set a reload value

(TH1) that causes Timer 1 to overflow at a frequency appropriate to generate a baud rate.

The baud rate of 115200 bps is used in this project. This was set by the program line:



SM0 SM1 Serial Mode Explanation Baud Rate

0 0 0 8-bit Shift Register Oscillator / 12

0 1 1 8-bit UART Set by Timer 1 (*)

1 0 2 9-bit UART Oscillator / 64 (*)

1 1 3 9-bit UART Set by Timer 1 (*)

Application and future development

The project can be applied to areas of maximum security concern like:-

• Banks, treasury and jewelry

• It can be used for the military purpose for security of restricted zones

• It can also be used the reverse way. i.e. controlling appliances by using

SMS messages like switching fan, freezers and other on/off controlled

devices.

Conclusion

• Assembly language programming is a very good choice for

designing embedded systems. It may have some discomforts

compared with high-level languages but have good flexibility

and is compact, can be applied with in very low memory

spaces

• As SMS is much cheaper in today time it is economical to

exploit such technology for application like our system.

• The system gives real time alert to the user.

• The system uses the reliability of the existing cellular network

• The total system is hidden and can be made very small in size

so that is cannot be exposed to or detected by thief.

• The system can be made more faithful and reliable by

increasing authorized security personnel or user, and if there is

network problem for one authorized user or security

personnel then the call goes to other user or security persons.

• The total system cost and power consumption is very low.

• The system is very flexible so that by changing the sensors

adding signal conditioning circuits and by modifying the

assembly program it can be applied to respond for many

different situations.

Recommendation

The system, as explained earlier, is very important in many areas and we

recommend our campus, MU, to be one of the beneficiaries of such

systems.

As we’ve tried to express before, such microcontroller projects had not

been made before in our department so we recommend our department

staff take the initiative to support such projects and give the required

support so that such projects could perform well students could share their

knowledge for the benefit of the society.

We recommend our department have very good record of all its resources

which is available for students and can serve as a good standing point for

prospective projects in the future.

We highly recommend the establishment of technology research centers so

that many different professional and beginner technologists could apply

their knowledge and contribute for the development of our country.

Reference materials

http://www.wikipedia.com/

http://www.gsmforum.com/

http://www.sonsivri.com/

http://www.freebsd.org/

http://www.activeexperts.com/

http://www.dreamfabric.com/sms/

http://www.8052.com

http://www.embedtronics.com/nokia/fbus.html

Appendix a: source code for GSM based security system

; SOFTWARE COMMENTS

ORG 8000H

MOV 8FH,#01H ;SELECT 6 MACHINE CYCLE MODE

LJMP MAIN

ORG 9400H; MAIN PROGRAM

MAIN: SETB IT1; SELECT EXTERNAL INTERRUPT 1 AS EDGE TRI

MOV IE, #84H; ENABLE EXTERNAL INTERRUPT 1

HERE: SJMP HERE; ISR OF INTERRUPT

ORG 0013H

LJMP HERE1; long jump to HERE1

RETI

ORG 807FH

HERE1: MOV PCON, #80H; TO SET SMOD BIT FOR DOUBLE BAUD RATE




SETB TR1 ; START TIMER 1

CLR TI


AAAA: JNB TI, AAAA

CLR TI

MOV SBUF, #'T'

AAAB: JNB TI, AAAB

CLR TI

LCALL ENTER


AAAC: JNB TI, AAAC

CLR TI

MOV SBUF, #'T'

AAAD: JNB TI, AAAD

CLR TI

LCALL ENTER

LCALL MODESEL

LCALL PDUFORMAT

LCALL DELAY

LCALL DELAY


AAAE: JNB TI, AAAE

CLR TI

MOV SBUF, #'T'

AAAF: JNB TI, AAAF

CLR TI

LCALL ENTER


AAAG: JNB TI, AAAG

CLR TI

MOV SBUF, #'T'

AAAH: JNB TI, AAAH

CLR TI

LCALL ENTER

LCALL MODESEL

LCALL PDUFORMAT1

LCALL DELAY

LCALL DELAY

LCALL CONTINEOUSDIALLING

ORG 8500H

MODESEL: MOV SBUF, #’A’; COMMAND FOR PDU MODE SELECTION

AAAI: JNB TI, AAAI

CLR TI

MOV SBUF, #'T'

AAAJ: JNB TI, AAAJ

CLR TI

MOV SBUF, #'+'

AAAK: JNB TI, AAAK

CLR TI

MOV SBUF, #'C'

AAAL: JNB TI, AAAL

CLR TI

MOV SBUF, #'M'

AAAM: JNB TI, AAAM

CLR TI

MOV SBUF, #'G'

AAAN: JNB TI, AAAN

CLR TI

MOV SBUF, #'F'

AAAO: JNB TI, AAAO

CLR TI

MOV SBUF, #'='

AAAP: JNB TI, AAAP

CLR TI

MOV SBUF, #'0'

AAAQ: JNB TI, AAAQ

CLR TI

LCALL ENTER

RET

ORG 8700H

PDUFORMAT: MOV SBUF, #’A’; COMMAND FOR PDU FORMAT

AAAR: JNB TI, AAAR

CLR TI

MOV SBUF, #'T'

AAAS: JNB TI, AAAS

CLR TI

MOV SBUF, #'+'

AAAT: JNB TI, AAAT

CLR TI

MOV SBUF, #'C'

AAAU: JNB TI, AAAU

CLR TI

MOV SBUF, #'M'

AAAV: JNB TI, AAAV

CLR TI

MOV SBUF, #'G'

AAAW: JNB TI, AAAW

CLR TI

MOV SBUF, #'S'

AAAX: JNB TI, AAAX

CLR TI

MOV SBUF, #'='

AAAY: JNB TI, AAAY

CLR TI

MOV SBUF, #'3'

AAAZ: JNB TI, AAAZ

CLR TI

MOV SBUF, #'3'

AZZQ: JNB TI, AZZQ

CLR TI

LCALL ENTER

LCALL DELAY

MOV SBUF, #'0'

AABB: JNB TI, AABB

CLR TI

MOV SBUF, #'0'

AABC: JNB TI, AABC

CLR TI

MOV SBUF, #'1'

AABD: JNB TI, AABD

CLR TI

MOV SBUF, #'1'

AABE: JNB TI, AABE

CLR TI

MOV SBUF, #'0'

AABF: JNB TI, AABF

CLR TI

MOV SBUF, #'0'

AABG: JNB TI, AABG

CLR TI

MOV SBUF, #'0'

AABH: JNB TI, AABH

CLR TI

MOV SBUF, #'A'

AABI: JNB TI, AABI

CLR TI

MOV SBUF, #'8'

AABJ: JNB TI, AABJ

CLR TI

MOV SBUF, #'1'

AABK: JNB TI, AABK

CLR TI

MOV SBUF, #'9'

AABL: JNB TI, AABL

CLR TI

MOV SBUF, #'0'

AABM: JNB TI, AABM

CLR TI

MOV SBUF, #'4'

AABN: JNB TI, AABN

CLR TI

MOV SBUF, #'1'

AABO: JNB TI, AABO

CLR TI

MOV SBUF, #'4'

AABP: JNB TI, AABP

CLR TI

MOV SBUF, #'7'

AABQ: JNB TI, AABQ

CLR TI

MOV SBUF, #'5'

AABR: JNB TI, AABR

CLR TI

MOV SBUF, #'0'

AABS: JNB TI, AABS

CLR TI

MOV SBUF, #'6'

AABT: JNB TI, AABT

CLR TI

MOV SBUF, #'4'

AAFA: JNB TI, AAFA

CLR TI

MOV SBUF, #'0'

AABV: JNB TI, AABV

CLR TI

MOV SBUF, #'0'

AABW: JNB TI, AABW

CLR TI

MOV SBUF, #'0'

AABX: JNB TI, AABX

CLR TI

MOV SBUF, #'0'

AABY: JNB TI, AABY

CLR TI

MOV SBUF, #'A'

AABZ: JNB TI, AABZ

CLR TI

MOV SBUF, #'A'

AACA: JNB TI, AACA

CLR TI

MOV SBUF, #'1'

AACB: JNB TI, AACB

CLR TI

MOV SBUF, #'6'

AACC: JNB TI, AACC

CLR TI

MOV SBUF, #'D'

AACD: JNB TI, AACD

CLR TI

MOV SBUF, #'7'

AACE: JNB TI, AACE

CLR TI

MOV SBUF, #'A'

AACF: JNB TI, AACF

CLR TI

MOV SBUF, #'0'

AACG: JNB TI, AACG

CLR TI

MOV SBUF, #'D'

AACH: JNB TI, AACH

CLR TI

MOV SBUF, #'4'

AACI: JNB TI, AACI

CLR TI

MOV SBUF, #'9'

AACJ: JNB TI, AACJ

CLR TI

MOV SBUF, #'9'

AACK: JNB TI, AACK

CLR TI

MOV SBUF, #'7'

AACL: JNB TI, AACL

CLR TI

MOV SBUF, #'4'

AACM: JNB TI, AACM

CLR TI

MOV SBUF, #'1'

AAFB: JNB TI, AAFB

CLR TI

MOV SBUF, #'E'

AAFC: JNB TI, AAFC

CLR TI

MOV SBUF, #'4'

AAFD: JNB TI, AAFD

CLR TI

MOV SBUF, #'3'

AAFE: JNB TI, AAFE

CLR TI

MOV SBUF, #'A'

AAFF: JNB TI, AAFF

CLR TI

MOV SBUF, #'0'

AAFG: JNB TI, AAFG

CLR TI

MOV SBUF, #'6'

AAFH: JNB TI, AAFH

CLR TI

MOV SBUF, #'3'

AAFI: JNB TI, AAFI

CLR TI

MOV SBUF, #'9'

AAFJ: JNB TI, AAFJ

CLR TI

MOV SBUF, #'0'

AAFK: JNB TI, AAFK

CLR TI

MOV SBUF, #'5'

AAFL: JNB TI, AAFL

CLR TI

MOV SBUF, #'A'

AAFM: JNB TI, AAFM

CLR TI

MOV SBUF, #'0'

AAFN: JNB TI, AAFN

CLR TI

MOV SBUF, #'4'

AAFO: JNB TI, AAFO

CLR TI

MOV SBUF, #'2'

AAFP: JNB TI, AAFP

CLR TI

MOV SBUF, #'5'

AAFQ: JNB TI, AAFQ

CLR TI

MOV SBUF, #'9'

AAFR: JNB TI, AAFR

CLR TI

MOV SBUF, #'D'

AAFS: JNB TI, AAFS

CLR TI

MOV SBUF, #'5'

AAFT: JNB TI, AAFT

CLR TI

MOV SBUF, #'4'

AAFU: JNB TI, AAFU

CLR TI

MOV SBUF, #'6'

AAFV: JNB TI, AAFV

CLR TI

MOV SBUF, #'9'

AAFX: JNB TI, AAFX

CLR TI

MOV SBUF, #'9'

AAFY: JNB TI, AAFY

CLR TI

MOV SBUF, #'5'

AAFZ: JNB TI, AAFZ

CLR TI

MOV SBUF, #'5'

AAGA: JNB TI, AAGA

CLR TI

MOV SBUF, #'8'

AAGB: JNB TI, AAGB

CLR TI

MOV SBUF, #'2'

AAGC: JNB TI, AAGC

CLR TI

MOV SBUF, #'4'

AAGD: JNB TI, AAGD

CLR TI

MOV SBUF, #'0'

AAGE: JNB TI, AAGE

CLR TI

MOV SBUF, #'2'

AACN: JNB TI, AACN

CLR TI

MOV SBUF, #1AH

AACO: JNB TI, AACO

CLR TI

RET

ORG 8B00H

PDUFORMAT1: MOV SBUF, #’A’; COMMAND FOR PDU FORMAT

AACP: JNB TI, AACP

CLR TI

MOV SBUF, #'T'

AACQ: JNB TI, AACQ

CLR TI

MOV SBUF, #'+'

AACR: JNB TI, AACR

CLR TI

MOV SBUF, #'C'

AACS: JNB TI, AACS

CLR TI

MOV SBUF, #'M'

AACT: JNB TI, AACT

CLR TI

MOV SBUF, #'G'

AACU: JNB TI, AACU

CLR TI

MOV SBUF, #'S'

AACV: JNB TI, AACV

CLR TI

MOV SBUF, #'='

AACW: JNB TI, AACW

CLR TI

MOV SBUF, #'3'

AACX: JNB TI, AACX

CLR TI

MOV SBUF, #'3'

AACY: JNB TI, AACY

CLR TI

LCALL ENTER

LCALL DELAY

MOV SBUF, #'0'

AAKY: JNB TI, AAKY

CLR TI

MOV SBUF, #'0'

AACZ: JNB TI, AACZ

CLR TI

MOV SBUF, #'1'

AADA: JNB TI, AADA

CLR TI

MOV SBU, #'1'

AADB: JNB TI, AADB

CLR TI

MOV SBUF, #'0'

AADC: JNB TI, AADC

CLR TI

MOV SBUF, #'0'

AADD: JNB TI, AADD

CLR TI

MOV SBUF, #'0'

AADE: JNB TI, AADE

CLR TI

MOV SBUF, #'A'

AADF: JNB TI, AADF

CLR TI

MOV SBUF, #'8'

AADG: JNB TI, AADG

CLR TI

MOV SBUF, #'1'

AADH: JNB TI, AADH

CLR TI

MOV SBUF, #'9'

AADJ: JNB TI, AADJ

CLR TI

MOV SBUF, #'0'

AADK: JNB TI, AADK

CLR TI

MOV SBUF, #'2'

AADL: JNB TI, AADL

CLR TI

MOV SBUF, #'1'

AADM: JNB TI, AADM

CLR TI

MOV SBUF, #'2'

AADN: JNB TI, AADN

CLR TI

MOV SBUF, #'0'

AADO: JNB TI, AADO

CLR TI

MOV SBUF, #'3'

AADP: JNB TI, AADP

CLR TI

MOV SBUF, #'3'

AADQ: JNB TI, AADQ

CLR TI

MOV SBUF, #'6'

AAGF: JNB TI, AAGF

CLR TI

MOV SBUF, #'3'

AADR: JNB TI, AADR

CLR TI

MOV SBUF, #'1'

AADS: JNB TI, AADS

CLR TI

MOV SBUF, #'0'

AADT: JNB TI, AADT

CLR TI

MOV SBUF, #'0'

AADU: JNB TI, AADU

CLR TI

MOV SBUF, #'0'

AADV: JNB TI, AADV

CLR TI

MOV SBUF, #'0'

AADW: JNB TI, AADW

CLR TI

MOV SBUF, #'A'

AADX: JNB TI, AADX

CLR TI

MOV SBUF, #'A'

AADY: JNB TI, AADY

CLR TI

MOV SBUF, #'1'

AADZ: JNB TI, AADZ

CLR TI

MOV SBUF, #'6'

AAHA: JNB TI, AAHA

CLR TI

MOV SBUF, #'D'

AAHB: JNB TI, AAHB

CLR TI

MOV SBUF, #'7'

AAHC: JNB TI, AAHC

CLR TI

MOV SBUF, #'A'

AAHD: JNB TI, AAHD

CLR TI

MOV SBUF, #'0'

AAHE: JNB TI, AAHE

CLR TI

MOV SBUF, #'D'

AAHF: JNB TI, AAHF

CLR TI

MOV SBUF, #'4'

AAHG: JNB TI, AAHG

CLR TI

MOV SBUF, #'9'

AAHH: JNB TI, AAHH

CLR TI

MOV SBUF, #'9'

AAHI: JNB TI, AAHI

CLR TI

MOV SBUF, #'7'

AAHJ: JNB TI, AAHJ

CLR TI

MOV SBUF, #'4'

AAHK: JNB TI, AAHK

CLR TI

MOV SBUF, #'1'

AAHL: JNB TI, AAHL

CLR TI

MOV SBUF, #'E'

AAHM: JNB TI, AAHM

CLR TI

MOV SBUF, #'4'

AAHN: JNB TI, AAHN

CLR TI

MOV SBUF, #'3'

AAHO: JNB TI, AAHO

CLR TI

MOV SBUF, #'A'

AAHP: JNB TI, AAHP

CLR TI

MOV SBUF, #'0'

AAHQ: JNB TI, AAHQ

CLR TI

MOV SBUF, #'6'

AAHR: JNB TI, AAHR

CLR TI

MOV SBUF, #'3'

AAHS: JNB TI, AAHS

CLR TI

MOV SBUF, #'9'

AAHT: JNB TI, AAHT

CLR TI

MOV SBUF, #'0'

AAHU: JNB TI, AAHU

CLR TI

MOV SBUF, #'5'

AAHV: JNB TI, AAHV

CLR TI

MOV SBUF, #'A'

AAHX: JNB TI, AAHX

CLR TI

MOV SBUF, #'0'

AAHY: JNB TI, AAHY

CLR TI

MOV SBUF, #'4'

AAHZ: JNB TI, AAHZ

CLR TI

MOV SBUF, #'2'

AAIA: JNB TI, AAIA

CLR TI

MOV SBUF, #'5'

AAIB: JNB TI, AAIB

CLR TI

MOV SBUF, #'9'

AAIC: JNB TI, AAIC

CLR TI

MOV SBUF, #'D'

AAID: JNB TI, AAID

CLR TI

MOV SBUF, #'5'

AAIE: JNB TI, AAIE

CLR TI

MOV SBUF, #'4'

AAIF: JNB TI, AAIF

CLR TI

MOV SBUF, #'6'

AAIG: JNB TI, AAIG

CLR TI

MOV SBUF, #'9'

AAIH: JNB TI, AAIH

CLR TI

MOV SBUF, #'9'

AAII: JNB TI, AAII

CLR TI

MOV SBUF, #'5'

AAIJ: JNB TI, AAIJ

CLR TI

MOV SBUF, #'5'

AAIK: JNB TI, AAIK

CLR TI

MOV SBUF, #'8'

AAIL: JNB TI, AAIL

CLR TI

MOV SBUF, #'2'

AAIM: JNB TI, AAIM

CLR TI

MOV SBUF, #'4'

AAIN: JNB TI, AAIN

CLR TI

MOV SBUF, #'0'

AAIO: JNB TI, AAIO

CLR TI

MOV SBUF, #'2'

AAEK: JNB TI, AAEK

CLR TI

MOV SBUF, #1AH

AAEL: JNB TI, AAEL

CLR TI

RET

ORG 9000H

ENTER: MOV SBUF, #0DH; THIS IS CARRIAGE RETURNS i.e. CR

AAEM: JNB TI, AAEM

CLR TI

MOV SBUF, #0AH ; THIS IS LINE FEED i.e. LF

AAEN: JNB TI, AAEN

CLR TI

RET

ORG 9100H

DELAY: MOV R0, #0FFH

MOV R1, #0FFH

MOV R2, #3FH

BBB: DJNZ R0, BBB; 5 SEC DELAYS

DJNZ R1, BBB

DJNZ R2, BBB

RET

ORG 9200H

CONTINEOUSDIALLING:

HERE22: MOV SBUF, #'A'; COMMAND FOR ANOTHER NUMBER DIALLING

BBC: JNB TI, BBC

CLR TI

MOV SBUF, #'T'

BBD: JNB TI, BBD

CLR TI

MOV SBUF, #'D'

BBE: JNB TI, BBE

CLR TI

MOV SBUF, #'='

BBF: JNB TI, BBF

CLR TI

MOV SBUF, #'9'

BBG: JNB TI, BBG

CLR TI

MOV SBUF, #'1'

BBH: JNB TI, BBH

CLR TI

MOV SBUF, #'4'

BBI: JNB TI, BBI

CLR TI

MOV SBUF, #'7'

BBJ: JNB TI, BBJ

CLR TI

MOV SBUF, #'4'

BBK: JNB TI, BBK

CLR TI

MOV SBUF, #'0'

BBL: JNB TI, BBL

CLR TI

MOV SBUF, #'5'

BBM: JNB TI, BBM

CLR TI

MOV SBUF, #'4'

BBN: JNB TI, BBN

CLR TI

MOV SBUF, #'6'

BBP: JNB TI, BBP

CLR TI

MOV SBUF, #';'

BBQ: JNB TI, BBQ

CLR TI

MOV SBUF, #0DH; THIS IS CARRIAGE RETURN I.E CR

BBR: JNB TI, BBR

CLR TI

MOV SBUF, #0AH; THIS IS LINE FEED I.E LF

BBS: JNB TI, BBS

CLR TI

MOV SBUF, #’A’; COMMAND FOR DIALLING MOBILE

BBT: JNB TI, BBT

CLR TI

MOV SBUF, #'T'

BBU: JNB TI, BBU

CLR TI

MOV SBUF, #'D'

BBV: JNB TI, BBV

CLR TI

MOV SBUF, #'='

BBW: JNB TI, BBW

CLR TI

MOV SBUF, #'9'

BBX: JNB TI, BBX

CLR TI

MOV SBUF, #'1'

BBY: JNB TI, BBY

CLR TI

MOV SBUF, #'3'

BBZ: JNB TI, BBZ

CLR TI

MOV SBUF, #'8'

BCC: JNB TI, BCC

CLR TI

MOV SBUF, #'2'

BCD: JNB TI, BCD

CLR TI

MOV SBUF, #'6'

BCE: JNB TI, BCE

CLR TI

MOV SBUF, #'8'

BCF: JNB TI, BCF

CLR TI

MOV SBUF, #'8'

BCG: JNB TI, BCG

CLR TI

MOV SBUF, #'2'

BCI: JNB TI,BCI

CLR TI

MOV SBUF, #';'

BCJ: JNB TI, BCJ

CLR TI

MOV SBUF, #0DH ; THIS IS CARRIAGE RETURN I.E CR TO EXECUTE COMMAND

BCK: JNB TI, BCK

CLR TI

MOV SBUF, #0AH; THIS IS LINE FEED I.E LF TO EXECUTE COMMAND

BCL: JNB TI, BCL

CLR TI

LJMP HERE22

END

GSM based security system

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Transcript of GSM based security system