Micro Controller 8051_89S52 Embedded C Programming

8/10/2019 Micro Controller 8051_89S52 Embedded C Programming

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1 010 101 010 100 1 010 1010 101 010 1

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1 010 101 010 100 1 010 1010 101 010 1

0 10 10 10 10 10 01 01 1 01 01 01 01 01 01 01 0

0 10 10 10 10 01 01 01 01 0 1 01 01 01 01 01 01 01 01

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01 010 1010 101 001 0 101 010 101 010 1

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1 01 01 01 01 01 00 10 0 10 10 10 10 10 10 10

1 01 01 01 01 00 10 10 10 0 10 10 10 10 10 10 10 1

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1 010 1010 101 001 10 101 010 101 010

01 010 1010 101 00 0 101 010 101 010 1

01 010 1010 101 00 0 101 010 101 010 1

01 010 1010 101 001 10 101 010 101 010

0 10 10 10 10 10 01 01 0 0 10 10 10 10 10 10 10 1

1 01 0 10 1 00 1 01 0 10 1 01 1 01 0 10 1 01 0 10 1 01 0 10

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ResearchDesign Lab

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Microcontroller 8051/89S52Embedded C Programming

Getting Stated with Keil Software

Introduction to Embedded C

Interfacing Examples

Mini Projects on GSM, Xbee & Bluetooth


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RESEARCH DESIGN LABS | VOLUME 1, ISSUE 1 WWW.RESEARCHDESIGNLAB.COM

Index

Embedded Systems 8051/89S52 Microcontroller-Introduction 1

Keil-Introduction 2

Creating a new project 2

Creating a new source file 5

Creating HEX for the Part 9

Testing Program in Debugger 12

Running the Keil Debugger (Simulation) 14

LED Blinking using 8051 Microcontroller and Keil AT89S52 17

LCD Keypad interfacing using 8051 Microcontroller and Keil AT89S52 19

LCD Keypad and Relays interfacing using 8051 Microcontroller and Keil AT89S52 23

Serial Communication 28

Simple Serial interfacing using 8051 Microcontroller and Keil AT89S52 30

Bluetooth and Relays interfacing using 8051 Microcontroller and Keil AT89S52 34

Keypad and XBee interfacing using 8051 Microcontroller and Keil AT89S52 37

LEDs and XBee interfacing using 8051 Microcontroller and Keil AT89S52 41

GSM Modem and LCD interfacing using 8051 Microcontroller and Keil AT89S52 44

Analog to digital conversion in 8051 Microcontroller and Keil-AT89S52 52


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RESEARCH DESIGN LABS | VOLUME 1, ISSUE 1 P1 WWW.RESEARCHDESIGNLAB.COMI

Embedded Systems8051/89S52 Microcontroller

Introduction

The 8051 microcontroller is one of the most

popular general purpose microcontrollers in

use today. The 8051 is an 8-bit microcontroller

which means that most available operations

are limited to 8 bits. 8051 chips are used in a

wide variety of control systems, telecom

applications, robotics as well as in the

automotive industry.

There are 4 8-bit ports: P0, P1, P2 and P3.

PORT P1 (Pins 1 to 8): The port P1 is a general

purpose input/output port which can be used

for a variety of interfacing tasks. The other

ports P0, P2 and P3 have dual roles or

additional functions associated with them

based upon the context of their usage. The

port 1 output buffers can sink/source four TTL

inputs. When 1s are written to portn1 pins are

pulled high by the internal pull-ups and can be

used as inputs.

Fig A.Pin description of 8051

PORT P3 (Pins 10 to 17): PORT P3 acts as a normal IO port, but Port P3 has additional functions such

as, serial transmit and receive pins, 2 external interrupt pins, 2 external counter inputs, read and

write pins for memory access.

PORT P2 (pins 21 to 28): PORT P2 can also be used as a general purpose 8 bit port when no external

memory is present, but if external memory access is required then PORT P2 will act as an address bus

in conjunction with PORT P0 to access external memory. PORT P2 acts as A8-A15, as can be seen fromfig 1.1

PORT P0 (pins 32 to 39)P0 can be used as a general purpose 8 bit port when no external memory is

present, but if external memory access is required then PORT P0 acts as a multiplexed address and

data bus that can be used to access external memory in conjunction with PORT P2. P0 acts as AD0-

AD7, as can be seen from fig 1.1

Overview:

Ports:


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RESEARCH DESIGN LABS | VOLUME 1, ISSUE 1 WWW.RESEARCHDESIGNLAB.COMP2I

Keil provides a broad range of development tools like ANSI C compiler, macro assembler, debuggers

and simulators, linkers, IDE, library managers, real-time clock operating systems and evaluation

boards for 8051.

Install Keil by following the instructions sets provided in your software.

1) Open Keil.

2) Select New Vision Project from the Project Menu.

Keil

Creating a new project


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3) Name the project Led1.

4) Click on the Save Button.

5) The device window will be displayed. Select the manufacturer of the IC.

Here let us use ATMEL AT89S52

6) Double Click on Atmel.

Tips

IR ObstacleSensor

Quick Overview

Based on a simple basic

Idea, this IR obstacle

sensor, is easy to build,

easy to calibrate and

still, it provides a

detection range of 10-

30 cm. This sensor can

be used for most indoor

applications where noimportant ambient light

is present. It is the same

principle in ALL Infra-

Red proximity sensors.

The basic idea is to send

infra red light through

IR-LEDs, which is then

reflected by any object

in front of the sensor.

Code & Schematic

For more detailswww.researchdesignlab.com


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7) Scroll down and select AT89S52

8) Click OK9) Choose No.

Tips

CarbonMonoxideSensor

Quick Overview

M Q - 7 g a s s e n s o r

composed by micro

AL2O3 ceramic tube, Tin

Dioxide (SnO2) sensitive

layer , measur ingelectrode and heater

are fixed into a crust

made by plastic and

stainless steel net. The

h e a t e r p r o v i d e s

n e c e s s a r y w o r k

conditions for work of

sensitive components.

Code & Schematic



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Creating a

new source file

1)Click File Menu and

select New.

2) A new window will

open up in the Keil IDE.

3) Let us write a simple

code that would toggle

the status of Port 1 witha small delay.


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4) Click on File menu

and select Save as

5) Name the file

Led1_blinking.c

6) Click the Save Button

7) In the Project

Workspace window,

click on the +

symbol in front of Target1.

Tips

Quick Overview

This is a simple-to-use liquefied petroleum gas (LPG) sensor,

suitable for sensing LPG (composed of mostly propane and

butane) concentrations in the air. Used in gas leakage

detecting equipments for detecting of LPG, iso-butane,

propane, LNG combustible gases. If output goes above a

preset range the output is low else high in idle condition.

Code & Schematic

For more detailswww.researchdesignlab.com Gas Sensor


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8) Below that Source Group 1 would appear, right click on it.

9) Click on Add Files

to Group Source

Group 1

10) Select

Led1_blinking.c11) Click Add button

12) Click Close button.

Tips

Digital SoilMoistureSensor

Quick Overview

This sensor can be used

to test the moisture of

soil, when the soil is

having water shortage,

the module output is at

high level, else the

output is at low level.

By using this sensor one

can automatically water

the flower plant, or any

other plants requiring

automatic watering

technique. Module

triple output mode,

digital output is simple,

analog output more

accurate, serial output

with exact readings.


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13) Click Close button.

Expand the Source

Group 1 in the tree

menu to ensure that

the file was added to

the project.

Tips

Code & Schematic


DigitalHeart BeatSensor

Quick Overview

This heart beat sensor is designed to give

digital output of heart beat when a finger is

placed on it. When the heartbeat detector is

working, the top-most LED flashes with each

heart beat. This digital output can be

connected to micro controller directly to

measure the Beats Per Minute (BPM) rate. It

works on the principle of light modulation by

blood flow through finger at each pulse.

Module dual output mode, digital output is

simple, serial output with exact readings.


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Creating HEX for the

Part

1) Right click on Target

1 in Tree menu

2) Select Options for

Target Target 1

3) Select Target Tab

4) Change Xtal (Mhz) from 33.0 to 11.0592

Tips

Analog

LightIntensitySensor

Quick Overview

Light dependent resistor

(LDR), suitable for use in

projects which require a

device or circuit to be

automatically switched

on or off in darkness or

light. As the amount of

light falling on this LDR

increases, its resistance

decreases. The light

detector itself is just

5mm in diameter.Analog

output more accurate.

Code & Schematic



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RESEARCH DESIGN LABS | VOLUME 1, ISSUE 1 P10 WWW.RESEARCHDESIGNLAB.COMI

5) Select Output Tab

6) Click on Create

Hex File check box

7) Click OK Button

8. Click on Project

Menu and select

Rebuild all Target

Files


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9. In the Build Window it should report 0 Errors (s), 0 Warnings

10. You are now ready to Program your Part

Tips

Code & Schematic


DigitalVibration

Sensor

Quick Overview

This basic piezo sensor can be used in anti-theft

devices, electronic locks, mechanical equipment

vibration detection, sound gesture application and

detection range bull's-eye counts vibration testing

occasions. These vibration levels could be given to

any controller/processor and necessary decisions

could be taken through it. Module triple output

mode, digital output is simple, analog output more

accurate, serial output with exact readings.


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Testing Program in Debugger

1) Click on the File Menu and select Save

2)Click on Project Menu and select Rebuild all Target Files

Tips

DigitalLightIntensitySensor

Quick Overview

Light dependent resistor

(LDR), suitable for use inprojects which require a

device or circuit to be

automatically switched

on or off in darkness or

light. As the amount of

light falling on this LDR

increases, its resistance

decreases. The light

detector itself is just

5mm in d iameter .

Module triple output

mode, digital output issimple, analog output

more accurate, serial

output with exact

readings.

Code & Schematic



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3) In the Build Window it should report 0 Errors (s), 0 Warnings

4) Click on Debug Menu and Select Start/Stop Debug Session.

5) If you are using a free version of Keil the dialog appears. Click OK.

Tips

SerialUltrasonicDistanceMeasure

Quick Overview

Ultrasonic DistanceSensor comes with an

ASCII serial O/P and

prov ided op t imum

ranging & detection of

long to short distance

ranges. Owing to their

stable, precise, non-

contact and accurate

distance measurements

from about 2 cm to 4

m e t e r s . C o m p a c t l y

designed, easy usable,

high ranging and easily

interfaced upon micro

controllers RX and TX

pin.

Code & Schematic



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Running the Keil Debugger (Simulation)

1) The Keil Debugger should be now running.

2) Click on Peripherals. Select I/O Ports, Select Port 1.

Tips

UltrasonicRangingSensor

Quick Overview

U l t r a s o n i c s e n s o r

provides stable and

a c c u r a te d i s t a n c e

measurements from

2cm to 450cm. It has an

focus of less than 15

degrees and an accuracy

of about 2mm.

Code & SchematicFor more detailswww.researchdesignlab.com


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3) A new window

should port will pop

up. This represents

the Port and Pins

4) To execute your code Click Run. The Parallel Port 1 Box status

should change as a continuous loop.

Tips

UltrasonicObstacle

Sensor

Quick Overview

Used to detect the move

of human or object.

Suitable for indoor and

outdoor burglar proof

application, vehicle

a p p l i c a t i o n , A T M

survillence camera etc.

Code & Schematic



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5) To exit out, first Click on Debug Menu and Select Stop Running

6) And then Click on

Debug Menu and

Select Start/Stop

Debug Session

Tips

GyroSensor

Quick Overview

The L3G4200DTR is a

low-power, three-axis

angular rate sensor, able

t o p r o v i d e

u n p r e c e d e n t e d

stablility of zero rate

level and sensitivity over

temperature and time.It

inc ludes a sensing

element and an IC

interface capable of

providing the measured

angular rate to the

external world through a

d i g i t a l i n t e r f a c e

(I2C/SPI).

Code & SchematicFor more detailswww.researchdesignlab.com


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Learn embedded C programming in 8051

Circuit and Working:

Fig.1 shows the circuit of simple

8051 Microcontroller interfaced

with LEDs.

Here are 3 simple programs for

controlling LEDs through simple

Embedded C programming in

Microcontroller.

Program 1 shows how to control

the entire port by toggling 8

LEDs.

Program 2 shows how to controlsingle I/O pin of the controller

one by one just like a Decimal

counter output.

Testing:

1) Write the program as shown below and generate the hex

file by the instructions provided in chapter 1.

2) Burn the code with the help of burner to the controller.

3) Power ON your microcontroller and check the result as per

your program.

Components/modules required :

1) 8051 project board (assembled/non assembled kit).

2) 5V DC source.

3) 8 LEDs.

4) Resistors (1Kx8).5) IC AT89S52.

6) 8051 IC burner.

7) Connectors and cables.

Fig 1. Circuit Diagram for LCD and 1x4 keypad interfacing

LED Blinking using 8051 Microcontroller and Keil AT89S52


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Program 1:

#include

#define LEDPORT P2

void delay();void main()

{

P2=0X00;

while(1)

{

LEDPORT =0XFF;

delay();

LEDPORT =0X00;

delay();

}}

void delay()

{

unsigned int x=60000;

while (x--) ;

}

// special function register

//declarations for the

// intended 8051 derivative

//Defining Port 2 as the

//'LEDPORT'

// Function prototype declaration//Main Code

//Set Port 2 all bits to 0

//infinite loop

//Set LEDPORT all bits to 1

// Wait for a small delay

//Set LEDPORT all bits to 0

// Wait for small delay

// Delay Routine

// larger the value of x

//the more is the delay.

// executes this statement

// until x decrements to 0

Program 2:#include

void delay();

sbit LED0=P2^0;

sbit LED1=P2^1;

sbit LED2=P2^2;

sbit LED3=P2^3;

sbit LED4=P2^4;

sbit LED5=P2^5;sbit LED6=P2^6;

sbit LED7=P2^7;

void main()//Main Code

{

P1=0x00;

while(1)

{

LED0=1;

delay();

LED1=1;

delay();

//special function register declarations

//for the intended 8051 derivative

// Function prototype declaration

//Define Port Pin P2.0 as LED0





//Define Port Pin P2.5 as LED5//Define Port Pin P2.6 as LED6



// Continuous loop

//Turn ON LED0

//Wait for a small delay

//Turn ON LED1


Tips

CurrentSensor 20A

Quick Overview

The ACS712 provides

economical and precise

solutions for AC or DC

current sensing in

industrial, commercial,

and communications

systems. The devicepackage allows for easy

implementation by the

c u s t o m e r . T yp i c a l

applications include

motor control, load

d e t e c t i o n a n d

m a n a g e m e n t ,

switchmode power

s u p p l i e s , a n d

o v e r c u r r e n t f a u l t

protection. The device

is not intended fora u t o m o t i v e

applications.

Code & Schematic



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LED2=1;

delay();

LED3=1;

delay();

LED4=1;

delay();

LED5=1;

delay();

LED6=1;

delay();

LED7=1;

delay();

P1=0x00;

delay();

}

}void delay()

{

unsigned int x=60000

while (x--);

}

//Turn ON LED2


//Turn ON LED3


//Turn ON LED4


//Turn ON LED5


//Turn ON LED6


//Turn ON LED7


//Turn OFF all LED's


// Delay Routine

// larger the value of x the

//more is the delay.


//until x decrements to 0

LCD Keypad interfacing using 8051

Microcontroller and Keil AT89S52


Components/modules required:

Fig.2 shows the circuit of simple 8051

Microcontroller interfaced with LCD and

1x4 Keypad.

Here is a simple program for interfacing

LCD and keypad through simple

Embedded C programming in

Microcontroller.

Program 3 demonstrates how to display in

a LCD when an event occurs like a key is

being pressed.

1) 8051 project board

(assembled/non assembled kit).

2) 5V DC source.

3) LCD interfacing Module

4) 4 Keys keypad

5) IC AT89S52.

6) 8051 IC burner.




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Program 3:

#include

#define LCD_PORT P2

sbit rs=P3^5;

sbit en=P3^7;sbit D7=P2^7;

sbit rw=P3^6;

sbit key1=P0^3;

sbit key2=P0^2;

sbit key3=P0^1;

sbit key4=P0^0;

void busy();

void CMD_WRT(unsigned char);

void LCD_WRT(unsigned char *);

void DATA_WRT(unsigned char);

void DELAY();

void main()

{

unsigned char CMD[]={0x38,0x0f,0x01,0x06,0x80};

unsigned char TEMP,i;

for(i=0;i


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if (key1 ==0)

{

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("Key 1 is pressed");

while(key1==0);

}

else if (key2 ==0)

{

CMD_WRT(0X01);

CMD_WRT(0X80);


while(key2==0);

}

else if (key3 ==0)

CMD_WRT(0X01);

CMD_WRT(0X80);


while(key3==0);

}

else if (key4 ==0)

{

CMD_WRT(0X01);

CMD_WRT(0X80);


while(key4==0);

}

else

{

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("No key Pressed");

DELAY();DELAY();

DELAY();

}

}

}

void busy()

{

D7=1;

rs=0;rw=1;

//Check whether switch 1 is being pressed

//Clears the LCD screen

//Moves the cursor to the beginning of the 1st line

//Writes the text within quotes in the LCD

//Wait until the switch has been released






//Check whether switch 3 is being pressed{













// A small delay for relaxation

//This Function checks whether the LCD is ready to receive next byte

//Keep D7 pin to High

//Keep RS to Low to select command register//RW=1 for read


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while(D7!=0)

{

en=0;

en=1;

}

}

void CMD_WRT(unsigned char val)

{

busy();

LCD_PORT=val;

rs=0;

rw=0;

en=1;

en=0;}

void LCD_WRT(unsigned char *string)

{

while(*string)

DATA_WRT(*string++);

}

void DATA_WRT(unsigned char ch)

{

busy();

LCD_PORT = ch;

rs=1;

rw=0;

en=1;

en=0;

}

void DELAY()

{

unsigned int X=60000,Y=60000;

while(X--);

while(Y--);

}

//Monitor D7 pin until it gets low

//Provide a latch pulse from low to high to EN

//This Function is used to write commands into the LCD

//Execute busy function to know whether the LCD is

//ready to receive any data/command

//Put the variable val into LCD_PORT which is

//connected to LCD data pins

//Keep RS to Low to select command register

// RW=0 for write

//Provide a latch pulse from High to Low to EN

//This Function is used to write Strings into the LCD

//increment from the beginning of the string until a

//null character is detected (end of the string)

//separates a single byte from the string

//This Function is used to write a byte of data into the LCD



//Put the variable ch into LCD_PORT which is


//Keep RS to High to select Data register

// RW=0 for write


//function for delay routine

// larger the value of X and Y the more is the

//delay.

//executes this statement until X decrements to 0

//executes this statement until Y decrements to 0


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LCD Keypad and Relays interfacing using 8051Microcontroller and Keil AT89S52


Fig.3.1 and Fig.3.2 shows the circuit of simple 8051

Microcontroller interfaced with LCD, 1x4 Keypad and 4 Relays.

Here is a simple Embedded C program for interfacing 4 Relaysto a 8051 Microcontroller which could be controlled by a key

press event through a 1x4 keypad, the result or state of the

relays being displayed on the LCD interfaced along with this.

Program 4 enables a user to toggle the state of relays by

pressing a key consequently the result gets displayed on the

LCD interfaced.

Fig 3.2.Circuit Diagram for Relay LCDand 1x4 keypad interfacing- Part 2.

Fig 3.1.Circuit Diagram forRelay LCD and 1x4keypad interfacing- Part 1.




2) 12V and 5V DC source.3) LCD interfacing Module

4) 4 Keys keypad

5) 4 Relay Interfacing Board 12V

6) IC AT89S52.

7) 8051 IC burner.

8) Connectors and cables


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Program 4:

#include

#define LCD_PORT P2

sbit rs=P3^5;

sbit en=P3^7;

sbit D7=P2^7;

sbit rw=P3^6;

sbit key1=P0^3;

sbit key2=P0^2;sbit key3=P0^1;

sbit key4=P0^0;

sbit Relay1=P1^3;

sbit Relay2=P1^2;

sbit Relay3=P1^1;

sbit Relay4=P1^0;

void busy();




void DELAY();

void main()

{


unsigned char TEMP,i;

P1=0X00;

for(i=0;i


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CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("RDL");

DELAY();

DELAY();

DELAY();

DELAY();

while(1)

{

if (key1 ==0 && Relay1==0)

{

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("Relay 1 is ON");

Relay1=1;

while(key1==0);

}else if (key1 ==0 && Relay1==1)

{

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("Relay 1 is OFF");

Relay1=0;

while(key1==0);

}

else if (key2 ==0 && Relay2==0)

{

CMD_WRT(0X01);CMD_WRT(0X80);


Relay2=1;

while(key2==0);

}


{

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("Relay 2 is OFF");Relay2=0;

while(key2==0);

}


{

CMD_WRT(0X01);

CMD_WRT(0X80);


Relay3=1;

while(key3==0);

}

//This command clears the LCD screen

//This moves the cursor to the beginning of the 1st line

//Writes the text 'RDL' in the LCD

//These delay's will hold the above text 'RDL' for some time

//Continuous loop


//and Relay1 is OFF




//Turn ON Relay1



//and Relay1 is ON




//Turn OFF Relay1



//and Relay2 is OFF

//Clears the LCD screen//Moves the cursor to the beginning of the 1st line


//Turn ON Relay2



//and Relay2 is ON



//Writes the text within quotes in the LCD//Turn OFF Relay2



//and Relay3 is OFF




//Turn ON Relay3



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{

CMD_WRT(0X01);

CMD_WRT(0X80);


Relay3=0;

while(key3==0);}


{

CMD_WRT(0X01);

CMD_WRT(0X80);


Relay4=1;

while(key4==0);

}

else if (key4 ==0 && Relay4==1){

CMD_WRT(0X01);

CMD_WRT(0X80);


Relay4=0;

while(key4==0);

else

{

CMD_WRT(0X01);

CMD_WRT(0X80);LCD_WRT("Press any key..");

DELAY();

}

}

}

void busy(){

D7=1;

rs=0;

rw=1;

while(D7!=0)

{

en=0;

en=1;

}

}


//and Relay3 is ON




//Turn OFF Relay3



//and Relay4 is OFF




//Turn ON Relay4


//Check whether switch 4 is being pressed//and Relay4 is ON




//Turn OFF Relay4


}


//Moves the cursor to the beginning of the 1st line//Writes the text within quotes in the LCD

// A small delay for relaxation

//This Function checks whether the LCD is ready to receive

//next byte



// RW=1 for read




29/59



{

busy();

LCD_PORT=val;

rs=0;

rw=0;

en=1;

en=0;

}

void LCD_WRT(unsigned char *string){

while(*string)


}


{

busy();

LCD_PORT = ch;

rs=1;

rw=0;

en=1;

en=0;

}

void DELAY()

{

unsigned int X=60000;

while(X--);

}







// RW=0 for write



// increment from the beginning of the string until

//a null character is detected (end of the string)

//separates a single byte from the string


//Execute busy function to know whether the LCD

//is ready to receive any data/command//Put the variable ch into LCD_PORT which is



// RW=0 for write


//Function for delay routine

// larger the value of X the more is the delay.

//executes this statement until X decrements to 0


30/59


Asynchronous serial data communication is widely used for character-oriented transmissions. Each

character is placed in between start and stop bits, this is called framing. Block-oriented data

transfers use the synchronous method. The start bit is always one bit, but the stop bit can be one or

two bits. The start bit is always a 0 (low) and the stop bit(s) is 1 (high).

We need a line driver (voltage converter) to convert the R232s signals to TTL voltage levels that willbe acceptable to 8051s TxD and RxD pins.

The baud rate of 8051 system should match the baud rate of the PCs COM port.

Serial Communication

Fig 4.1Rs232 to TTLConversion

Fig 4.2Serial Transmissionof Character A


31/59


SM0, SM1

They determine the framing of

data by specifying the number

of bits per character, and the

start and stop bits.

REN (receive enable)It is a bit-addressable register

When it is high, it allows 8051 to

receive data on RxD pin If low,and should be picked up before data is framed with start andthe receiver is disable.it is lost. stop bits.

4. TR1 is set to 1 to start timer 1TI (transmit interrupt)Programming the 8051 to 5. TI is cleared by (TI=0;) TIWhen 8051 finishes the transfertransfer character bytes instructionof 8-bit Character It raises TIserially. 6. The character byte to beflag to indicate that it is ready1. TMOD register is loaded with transferred serially is written

to transfer another byte TI bit th e va lu e TM OD =0 X2 0, into SBUF registeris raised at the beginning of theindicating the use of timer 1 in 7. The TI flag bit is monitoredstop bitmode 2 (8-bit auto-reload) to with the use of instruction

set baud rate. while (TI==0); to see if theRI (receive interrupt)2. The TH1 is loaded with one of c h a r a c t e r h a s b e e nWhen 8051 receives data

the values to set baud rate for transferred completely.serially via RxD, it gets rid of theserial data transfer 8. To transfer the next byte, gostart and stop bits and places

3. The SCON register is loaded to step 5the byte in SBUF register Itwith the value 50H, indicatingraises the RI flag bit to indicateserial mode 1, where an 8-bitthat a byte has been received

Programming the 8051 to receive character bytes serially

1. TMOD register is loaded with the value TMOD=0X20, indicating the use of timer 1 in mode2

(8-bit auto-reload) to set baud rate

2. TH1 is loaded to set baud rate

3. The SCON register is loaded with the value SCON=0X50,indicating serial mode 1, where an 8-

bit data is framed with start and stop bits

4. TR1 is set to 1 to start timer 1

5. RI is cleared by RI=0; RI instruction6. The RI flag bit is monitored with the use of instruction while(RI==0); to see if an entire

character has been received yet.

7. When RI is raised, SBUF has the byte, its contents are moved into a safe place

8. To receive the next character, go to step 5

Fig 4.3: Serial Mode Selector


32/59



Fig.5 shows the circuit of simple 8051 Microcontroller interfaced with LEDs.

Here is a simple Embedded C program for interfacing 8 LEDs to a 8051 Microcontroller

which could be turned ON or OFF by sending few serial commands.

Program 5 enables a user to turn ON/OFF a series of LEDs by sending serial data. The

program is designed in such a way that a serial command A1 will turn ON the first LED

and A0 will turn of the same LED. Similarly B1 will turn ON the second LED and B0 will

turn of the same LED. This will continue for the remaining 6 LEDs. i.e. H1 and H0 would

turn ON and OFF last LED (8th LED) respectively. You can enter the inputs in any serial

window monitor software like Hyperterminal, Putty etc. Also you could design a GUI in

software like Matlab, .NET etc. which could be used to control these LEDs.


1) 8051 project board with RS232 interface (assembled/non assembled kit).

2) 5V DC source.

3) 8 LEDs.4) Resistors (1Kx8).

5) IC AT89S52.

6) 8051 IC burner.


Fig. 5 Circuit Diagram for Serial and LED interfacing

Simple Serial interfacing using 8051 Microcontroller and Keil AT89S52


33/59


#include

void delay();

sbit LED0=P2^0;

sbit LED1=P2^1;

sbit LED2=P2^2;

sbit LED3=P2^3;

sbit LED4=P2^4;

sbit LED5=P2^5;

sbit LED6=P2^6;

sbit LED7=P2^7;

unsigned char byte1,byte2;

void main()

{

TMOD=0X20;

SCON=0X50;

TH1=0XFD;

TR1=1;

delay();

TI=0;

SBUF='S';

while (TI==0);

TI=0;

delay();

P2=0x00;

while(1)

{

RI=0;

while(RI==0);

byte1=SBUF;

RI=0;while(RI==0);

byte2=SBUF;

RI=0;

delay();

delay();

if(byte1=='A')

{

if(byte2=='1')

{












// Variable declarations

// MAIN CODE

//Serial Initialization//use Timer 1, mode 2

//indicating serial mode 1, where an 8-bit

//data is framed with start and stop bits

//9600 baud rate

//Start timer

//Wait for a delay for serial initialization to finish

// Transmit 'S' to check whether the setup is ready

//Forcibly change the Transmit Interrupt Flag of 8051 to 0

//Move 'S' to serial buffer memory

//Wait until TI flag is set by hardware when an entire byte

//has been transmitted// Forcibly clear TI flag

//A small delay for relaxation


// continuous loop

//Forcibly clear the Receive Interrupt Flag of 8051 to 0

//Wait until RI flag is set by hardware when an entire byte

//has been received

//Move the received byte of data into variable 'byte1'

//Forcibly clear RI flag//Wait until RI flag is set by hardware when an entire byte

//has been received


//Forcibly clear RI flag

//Check whether the 1st byte of

//data is 'A'

//Check whether the 2nd byte of

//data is '1'


34/59


LED0=1;

delay();

}

else if(byte2=='0')

{

LED0=0;

delay();

}

}

else if(byte1=='B')

{

if(byte2=='1')

{

LED1=1;

delay();

}

else if(byte2=='0'){

LED1=0;

delay();

}

}

else if(byte1=='C')

{

if(byte2=='1')

{

LED2=1;

delay();}

else if(byte2=='0')

{

LED2=0;

delay();

}

}

else if(byte1=='D')

{

if(byte2=='1'){

LED3=1;

}

//Turn ON LED0



//data is '0'

//Turn OFF LED0



//data is 'B'


//data is '1'

//Turn ON LED1


//Check whether the 2nd byte of//data is '0'

//Turn OFF LED1



//data is 'C'


//data is '1'

//Turn ON LED2



//data is '0'

//Turn OFF LED2



//data is 'D'

//Check whether the 2nd byte of//data is '1'

//Turn ON LED3

Tips

SOIC to DIPAdapter 8-Pin

Quick Overview

Adapter for standard 8

SOIC SMD Parts to

convert to standard 8 Pin

DIP s ize.This SOIC

breakout board is a PCB

which will interface anSOIC package to 0.1"

(2.54mm) headers which

c a n b e u s e d o n

b r e a d b o a r d s f o r

p r o t o t y p i n g y o u r

projects.Simply solder-

on your 8-pin SOIC form-

factor IC, along with

some 0.1-inch-pitch

headers, and you will

h a v e a u s a b l e ,

breadboard-friendlyunit.

Code & Schematic



35/59


delay();

}

else if(byte2=='0')

{

LED3=0;

delay();

}}

else if(byte1=='E')

{

if(byte2=='1')

{

LED4=1;

delay();

}

else if(byte2=='0')

{

LED4=0;

delay();

}

}

else if(byte1=='F')

{

if(byte2=='1')

{

LED5=1;

delay();

}else if(byte2=='0')

{

LED5=0;

delay();

}

}

else if(byte1=='G')

{

if(byte2=='1')

{

LED6=1;

delay();

}

else if(byte2=='0')

{

LED6=0;

delay();

}

}

else if(byte1=='H')

{



//data is '0'

//Turn OFF LED3



//data is 'E'


//data is '1'

//Turn ON LED4



//data is '0'

//Turn OFF LED4



//data is 'F'


//data is '1

//Turn ON LED5



//data is '0'

//Turn OFF LED5



//data is 'G'


//data is '1'

//Turn ON LED6



//data is '0'

//Turn OFF LED6



//data is 'H'

Tips

CurrentSensor 05A

Code & Schematic


Quick Overview

The ACS712 provides

economical and precise

solutions for AC or DC

current sensing in

industrial, commercial,

and communications

systems. The device

package allows foreasyimplementation by the

c u s t o m e r . T yp i c a l

app l icat ions inc lude

motor control, load

d e t e c t i o n a n d

m a n a g e m e n t ,

switchmode power

s u p p l i e s , a n d

o v e r c u r r e n t f a u l t

protection. The device

is not intended for

a u t o m o t i v eapplications.


36/59


if(byte2=='1')

{

LED7=1;

delay();

}

else if(byte2=='0')

{LED7=0;

delay();

}

}

else

{

P2=0x00;

delay();

}}

}

void delay()

{


while (x--);

}


//data is '1'

//Turn ON LED7



//data is '0'//Turn OFF LED7


//Set Port 2 all bits to 0 if any

//other variable has been received


// Delay Routine

// larger the value of x

//the more is the delay.


//until x decrements to 0

Bluetooth and Relays interfacing

using 8051 Microcontroller and

Keil AT89S52


Fig.6 shows the circuit of simple

8051 Microcontroller interfaced

with Bluetooth and 4 relays.

Program 6 demonstrates how to

receive data through Bluetooth.




2) 5V and 12V DC source.

3) Bluetooth Module.

4) 12V 4 Relay board.5) IC AT89S52.

6) 8051 IC burner.


Fig .6 Circuit Diagram for Bluetooth and 4 Relay interfacing


37/59


Program 6:

#include

void delay();

sbit Relay1=P2^3;

sbit Relay2=P2^2;

sbit Relay3=P2^1;

sbit Relay4=P2^0;


void main()

{

TMOD=0X20;

SCON=0X50;

TH1=0XFD;

TR1=1;

delay();

TI=0;

SBUF='S';

while (TI==0);

TI=0;

delay();

P2=0x00;

while(1)

{

RI=0;

while(RI==0);

byte1=SBUF; '

RI=0;

while(RI==0);

byte2=SBUF;

RI=0;

if(byte1=='1')

{

if(byte2=='N')

{

Relay1=1;

}



//Function prototype declaration

// Relay Connections

//Relay 1 is connected to Port 2 pin 3





// MAIN CODE

//Serial Initialization

//use Timer 1, mode 2

//indicating serial mode 1,where an 8-bit data

//is framed with start and stop bits//9600 baud rate

//Start timer

//Wait for some time for serial initialization to finish


//Forcibly change the Transmit

//Interrupt Flag of 8051 to 0


//Wait until TI flag is set by hardware

//when an entire byte has been transmitted

// Forcibly clear TI flag



// continuous loop

//Forcibly clear the Receive

//Interrupt Flag of 8051 to 0

//Wait until RI flag is set by hardware

//when an entire byte has been received

//Move the received byte of data into variable 'byte1






//Check whether the 1st byte of data is '1'

//Check whether the 2nd byte of data is 'N'

//Turn ON Relay1


38/59


else if(byte2=='F')

{

Relay1=0;

}

}

else if(byte1=='2')

{if(byte2=='N')

{

Relay2=1;

}

else if(byte2=='F')

{

Relay2=0;

}

}

else if(byte1=='3'){

if(byte2=='N')

{

Relay3=1;

}

else if(byte2=='F')

{

Relay3=0;

}

}

else if(byte1=='4')

if(byte2=='N')

{

Relay4=1;

}

else if(byte2=='F')

{

Relay4=0;

}

}

else if(byte1=='X')

{

if(byte2=='N')

{

P2=0xFF;

}

else if(byte2=='F')

{

P2=0x00;

}

}

//Check whether the 2nd byte of data is 'F'

//Turn OFF Relay1



//Turn ON Relay2


//Turn OFF Relay2



//Turn ON Relay3


//Turn OFF Relay3

//Check whether the 1st byte of data is '4'{


//Turn ON Relay4


//Turn OFF Relay4

//Check whether the 1st byte of data is 'X'


//Turn ON all the Relays


//Turn OFF all the Relays


39/59


else

{

P2=0x00;

}

}

}

void delay()

{


while (x--);

}

//Clear Port 2 all bits to 0 if any other variable has been received

//Function for delay routine//Delay Routine

// larger the value of x the more is the delay.

// executes this statement until x decrements to 0

Fig.7 shows the circuit of simple 8051 Microcontroller interfaced with XBee and 1x4 Keypad.Program 7 demonstrates how to send data wirelessly when a key is being pressed.



2) 5V DC source.

3) XBee(S2)

4) XBee power supply board

5) 1X4 keys keypad.

6) IC AT89S52.

7) 8051 IC burner.



Keypad and XBee interfacing using 8051 Microcontroller and Keil AT89S52



40/59


Program 7:

#include

sbit key1=P0^3;

sbit key2=P0^2;

sbit key3=P0^1;sbit key4=P0^0;

void DELAY();

void main()

{

unsigned char flag1=0,flag2=0,flag3=0,flag4=0; //Variable declarations

TMOD=0X20;

SCON=0X50;

TH1=0XFD;TR1=1;

DELAY();

TI=0;

SBUF='S';

while (TI==0);

TI=0;

DELAY();

P1=0X00;

DELAY();while(1)

{

if (key1 ==0 && flag1==0)

{

SBUF='A';

while (TI==0);

TI=0;

flag1=1;

while(key1==0);DELAY();

}

else if (key1 ==0 && flag1==1)

{

SBUF='B';

while (TI==0);

TI=0;

flag1=0;

while(key1==0);

DELAY();}



// Keypad connections

//Switch 1 is connected to Port 0 pin 3

//Switch 2 is connected to Port 0 pin 2

//Switch 3 is connected to Port 0 pin 1//Switch 4 is connected to Port 0 pin 0

//Call Function declarations for delay



//indicating serial mode 1, where an 8-bit data is

//framed with start and stop bits

//9600 baud rate//Start timer

//Wait for a delay for serial initialization to finish


//Forcibly clear the Transmit Interrupt Flag of 8051 to 0


//Wait until TI flag is set by hardware when an

//entire byte has been transmitted

//Forcibly clear TI flag



//Continuous loop


//flag1 is Low

//Move 'A' to serial buffer memory




//Set flag1

//Wait until the switch has been released//A small delay for relaxation


//and flag1 is Low

//Move 'B' to serial buffer memory




//Clear flag1




41/59



{

SBUF='C';

while (TI==0);

TI=0;flag2=1;

while(key2==0);

DELAY();

}


{

SBUF='D';

while (TI==0);

TI=0;

flag2=0;

while(key2==0);

DELAY();

}


{

SBUF='E';

while (TI==0);

TI=0;

flag3=1;

while(key3==0);

DELAY();

}


{

SBUF='F';

while (TI==0);

TI=0;

flag3=0;

while(key3==0);

DELAY();

}


{

SBUF='G';

while (TI==0);


//and flag2 is Low

//Move 'C' to serial buffer memory



//Forcibly clear TI flag//Set flag2




//and flag2 is High

//Move 'D' to serial buffer memory




//Clear flag2




//and flag3 is Low

//Move 'E' to serial buffer memory


//when an entire byte has been transmitted//Forcibly clear TI flag

//Set flag3




//and flag3 is High

//Move 'F' to serial buffer memory


//when an entire byte has been transmitted// Forcibly clear TI flag

//Clear flag3




//and flag4 is Low

//Move 'G' to serial buffer memory

//Wait until TI flag is set by hardware//when an entire byte has been transmitted


42/59


TI=0;flag4=1;while(key4==0);DELAY();}else if (key4 ==0 &&flag4==1)

{SBUF='H';while (TI==0);

TI=0;flag4=0;while(key4==0);DELAY();}}}

void DELAY(){unsigned int X=60000;while(X--);}

// Forcibly clear TI flag//Set flag4//Wait until the switch has been released//A small delay for relaxation


//and flag4 is High

//Move 'H' to serial buffer memory//Wait until TI flag is set by hardware//when an entire byte has been transmitted// Forcibly clear TI flag//Clear flag4//Wait until the switch has been released//A small delay for relaxation


// larger the value of X the more is the delay.// executes this statement until / X decrements to 0

3 Axis Accelerometer

Quick Overview

3-axis accelerometer to now have an on-board 3.3V regulator -

making it a perfect choice for interfacing with a 5V microcontroller

such as the . This breakout comes with 3 analog outputs for X, Y and Z

axis breakout board. The ADXL335 is the latest and greatest from

Analog Devices, known for their exceptional quality MEMS devices.

The VCC takes up to 5V in and regulates it to 3.3V with an output pin.

The analog outputs are ratiometric: that means that 0g measurement

output is always at half of the 3.3V output (1.65V), -3g is at 0v and 3g

is at 3.3V with full scaling in between. Fully assembled and tested.

The XYZ filter capacitors are 0.1uF for a 50 Hz bandwidth

Tips

Code & Schematic

For more details

www.researchdesignlab.com


43/59


LEDs and XBee interfacing using 8051 Microcontroller and Keil AT89S52


Fig.8 shows the circuit of simple 8051 Microcontroller interfaced with XBee and 8 LEDs.

Program 8 demonstrates how to receive serial data wirelessly and toggle the state of a LED.



2) 5V DC source.

3) XBee(S2)

4) XBee power supply board

5) 8 LEDs.

6) Resistors (1Kx8).

7) IC AT89S52.

8) 8051 IC burner.


Fig. 8 Circuit Diagram for XBee and LED interfacing


44/59


Program 8:

#include

void delay();

sbit LED0=P2^0;

sbit LED1=P2^1;sbit LED2=P2^2;

sbit LED3=P2^3;

sbit LED4=P2^4;

sbit LED5=P2^5;

sbit LED6=P2^6;

sbit LED7=P2^7;


void main()

{

TMOD=0X20;

SCON=0X50;

TH1=0XFD;

TR1=1;

delay();

TI=0;

SBUF='S';

while (TI==0);

TI=0;

delay();

P2=0x00;

while(1)

{

RI=0;

while(RI==0);

byte1=SBUF;

RI=0;

if(byte1=='A')

{

LED0=1;

LED4=1;

}

else if(byte1=='B')





//Define Port Pin P2.1 as LED1//Define Port Pin P2.2 as LED2







// MAIN CODE



//indicating serial mode 1, where an 8-bit

//data is framed with start and stop bits

//9600 baud rate

//Start timer

//Wait for some time for serial initialization to finish


//Forcibly change the Transmit Interrupt//Flag of 8051 to 0







// continuous loop

//Forcibly clear the Receive Interrupt

//Flag of 8051 to 0





//Check whether the received byte of data is 'A'

//Turn on LED0

//Turn on LED4

//Check whether the received byte of data is 'B'


45/59


{

LED0=0;

LED4=0;

}

else if(byte1=='C')

{

LED1=1;

LED5=1;

}

else if(byte1=='D')

{

LED1=0;

LED5=0;

}

else if(byte1=='E')

{

LED2=1;LED6=1;

}

else if(byte1=='F')

{

LED2=0;

LED6=0;

}

else if(byte1=='G')

{

LED3=1;

LED7=1;}

else if(byte1=='H')

LED3=0;

LED7=0;

}

else

{

P2=0x00;

delay();

}

}

}

void delay()

{


while (x--);

}

//Turn off LED0

//Turn off LED4

//Check whether the received byte of data is 'C'

//Turn on LED1

//Turn on LED5

//Check whether the received byte of data is 'D'

//Turn off LED1

//Turn off LED5

//Check whether the received byte of data is 'E'

//Turn on LED2//Turn on LED6

//Check whether the received byte of data is 'F'

//Turn off LED2

//Turn off LED6

//Check whether the received byte of data is 'G'

//Turn on LED3

//Turn on LED7

//Check whether the received byte of data is 'H'

{

//Turn off LED3

//Turn off LED7


//if any other variable has been received//Wait for a small delay

// Delay Routine

// larger the value of x the more is the delay.

// executes this statement until x decrements to 0


46/59


GSM Modem and LCD interfacing using 8051 Microcontroller and Keil AT89S52


Fig.9 shows the circuit of simple 8051 Microcontroller interfaced with GSM Modem and LCD. The

Modem sends an SMS every time you turn on your microcontroller. Following this the modem will

be waiting for any message to be received, once a message has been received, the message will

be displayed on the LCD.

Program 9 demonstrates how to initialize GSM modem through AT commands via a serialinterface and send/receive a SMS through it.

Please note: GSM modem needs to be turned on at least 10 seconds before you turn on the micro

controller (GSM takes a few seconds to turn on)

Fig.9Circuit Diagramfor GSM Modem

and 16X2 LCD


1)8051 project board (assembled/non assembled kit).

2)5V and 12V,1A DC source.

3)GSM Module.

4)16X2 LCD interfacing module.

5)IC AT89S52.

6)8051 IC burner.7)Connectors and cables.


47/59


Program 9:

#include"reg52.h"

#define CR 0X0D

#define LF 0X0A

#define EOM 0X1A

#define LCD_PORT P2

sbit rs=P3^5;

sbit rw=P3^6;

sbit en=P3^7;

sbit D7=P2^7;

void busy();




void TRANSMIT(unsigned char *);

void transmit_byte(unsigned char );

void READ_SMS(void);

void SEND_CMD(unsigned char *BASE_ADD,unsigned char COUNT);

void SEND_CRLF(unsigned char);

unsigned char recv_byte (void);

void RX_REPLY();

void ENTER(void);

void DELAY();

unsigned char count12=0,message[50];

unsigned char byte1,k,temp;

unsigned char Test_Text[]="GSM Testing";

unsigned char code CMD_1[]="AT";

unsigned char code CMD_3[]="AT+CMGF=1";

unsigned char code CMD_4[]="AT+CMGD=1";

unsigned char code CMD_9[]="AT+CMGS=\"7411001407\"";

//Special function register declarations


//Define CR as 13

//Define LF as 10

//Define EOM as CNTRL+Z

// LCD connections//Define Port 2 as LCD Data pins

//Register Select is connected to Port 3 pin 5

//Read/Write is connected to Port 3 pin 6

//Enable is connected to Port 3 pin 7

//Data Pin D7 is connected to Port 2 pin 7

// Call function declarations

//This Function checks whether the LCD is ready to

//receive next byte

//This Function is used to write commands

//into the LCD//This Function is used to write Strings

//into the LCD

//This Function is used to write a byte of

//data into the LCD

//This Function is used to write Strings into

//the serial Port

//This Function is used to write a byte of

//data into the serial Port

//This function separates the text message from

//the SMS received

//This function sends GSM commands via the serial interface

//This function writes a 8 bit hex value into

//the serial interface

//This function receives a byte of data

//through the serial interface

//This function waits for a character 'K'(of OK) which

//the GSM modem replies for its commands

//This function is used to hit enter into the GSM

//modem whenever required


// Global variable declaration and initialization

// GSM commands declaration

//GSM Attention command

//GSM text initialization

//command

//Delete previous SMS

//command

//Edit the 10//digit destination number here


48/59


void main()

{


unsigned char I,TEMP,count=0;

for(i=0;i


49/59


SEND_CMD(CMD_3,9);

DELAY();

ENTER();

RX_REPLY();

DELAY();

SEND_CMD(CMD_4,9);

DELAY();

ENTER();

RX_REPLY();

DELAY();

SEND_CMD(CMD_9,20);

DELAY();

ENTER();DELAY();

TRANSMIT(Test_Text);

DELAY();

transmit_byte(EOM);

RX_REPLY();

DELAY();

CMD_WRT(0X01);

CMD_WRT(0X80);

LCD_WRT("TEXT SENT!!");DELAY();

while(1)

{

DELAY();

CMD_WRT(0XC0);

LCD_WRT("WAITING..");

DELAY();

READ_SMS();

DELAY();

}

}

void busy()

{

D7=1;

rs=0;

rw=1;while(D7!=0)

//Enter GSM text initialization command


//Hit enter

//Wait for GSM modem to respond


//Enter Delete previous SMS command to free up

//space for new SMS


//Hit enter



//Enter the command for sending the SMS to a

//destination number


//Hit enter//A small delay for relaxation

//Enter the text within the previously declared

//variable Test_Text


//Enter ASCII equivalent of CNTRL+Z



//This command clears the LCD screen

//This moves the cursor to the beginning of the 1st line

//Writes the text 'TEXT SENT!!' in the LCD//A small delay for relaxation

//Continuous loop


//This moves the cursor to the beginning of the 2nd line

//Writes the text 'WAITING..' from the current pointer

//of LCD


//Call 'READ_SMS()' function which waits until a SMS has been

//received and separates the text message from it





// RW=1 for read//Monitor D7 pin until it gets low


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SEND_CRLF(LF);

}

void SEND_CRLF(unsigned char CRLF)

{

SBUF=CRLF;

while(TI==0);

TI=0;

}

void SEND_CMD(unsigned char *BASE_ADD,unsigned char COUNT){

unsigned char I;

for(I=0;I


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{

en=0;

en=1;

}

}


{

busy();

LCD_PORT=val;

rs=0;

rw=0;

en=1;

en=0;

}


{

while(*string)


}


{

busy();

LCD_PORT = ch;

rs=1;

rw=0;

en=1;

en=0;

}

void DELAY(){

unsigned int X=60000,Y=60000;

while(X--);

while(Y--);

}

void ENTER(void)

{

SEND_CRLF(CR);








// RW=0 for write



// increment from the beginning of the string until a


// separates a single byte from the string


//Execute busy function to know whether the LCD//is ready to receive any data/command




// RW=0 for write



// larger the value of X and Y the more is

//the delay.

// executes this statement until X decrements to 0;

// executes this statement until Y decrements to 0;

//Function used for sending ENTER command to the GSM Modem

//Send the value CR(13) to the GSM modem via the

//serial interface


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// Function used to transmit a string of data into the serial interface

//execute the next statement till the end of the string

//Pass the 8 bit data located at the address location

// of the pointer to the function 'transmit_byte'

//Function used for sending an 8 bit data present on the variable// 'byte' to the serial interface

//Move the contents of the variable 'byte' to serial buffer memory

//Wait until TI flag is set by hardware when an entire byte has

//been transmitted


//This function waits until a SMS has been received and separates the text//message from it and displays it on the LCD

//GSM read SMS command

//Local Variables declaration and initialization

//Assign any value to byte other than '+'

//Breaks this loop only when '+' has been received, till then

//the variable 'byte' keeps waiting for '+' to be received

//Keep checking for the data received in the

//call function 'recv_byte'//A small delay for relaxation


//Enter the command used for reading a SMS

//Hit enter

//The string that comes next includes quotes(") along with other

//information like time, date, number etc. of the received SMS

//Wait for at least 8 such quotes(")

//Breaks this loop only when '"' has been received, till then

//the variable 'byte' keeps waiting for '"' to be received

//Keep checking for the data received in the call

//function 'recv_byte'

//Assign any value to byte other than '"'

//Assign any value to byte other than '13'

//Breaks this loop only when '13' has been received, till then

//the variable 'byte' keeps waiting for '13' to be received

//Keep checking for the data recieved in the//call function 'recv_byte'

void TRANSMIT(unsigned char *string)

{

while(*string)

transmit_byte(*string++);

}

void transmit_byte(unsigned char byte)

{

SBUF=byte;

while(!TI);

TI=0;

}

void READ_SMS(void)

{

unsigned char code CMD_5[]="AT+CMGR=1";

unsigned char byte,i=0, flag=0;

byte=0;

while(byte!='+')

{

byte=recv_byte();

}DELAY();

DELAY();

SEND_CMD(CMD_5,9);

ENTER();

for(i=0;i


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Analog to digital conversion in 8051/89c52 Microcontroller and Keil - ADC0804

Circuit and Working:Fig 10. shows the circuit of simple 8051 Microcontroller interfaced with LCD Display and analog

to digital converter IC ADC0804. After the connections are done properly, you will be able to

view the digital value on the LCD display.Program 10 demonstrates how to read the analog values through IC ADC0804. The output of this

IC will be an 8 bit value, this 8 bit value would be connected to a microcontroller. The

microcontroller is programmed in such a way to read the port pin values and display its

equivalent decimal value on the LCD display.



2) 5V DC source.

3) LCD interfacing Module.

4) IC ADC0804 with the circuit

connections as shown in Fig 10.2

5) IC AT89S52.

6) 8051 IC burner.


Fig10.1: Circuit Diagram for LCD and ADC interfacing-Part 1.


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Fig 10.2: Circuit Diagram for LCD and ADC interfacing-Part 2.

Programme 10#include

#include

#define adc_port P1

#define LCD_PORT P2

sbit rs=P3^5;

sbit rw=P3^6;

sbit en=P3^7;

sbit D7=P2^7;

void busy();




void CONVERT_DISPLAY(unsigned char);

void DELAY();

//Define Port 1 as ADC port Data pins

// LCD connections

//Define Port 2 as LCD Data pins

//Register Select is connected to Port 3 pin 5

//Read/Write is connected to Port 3 pin 6

//Enable is connected to Port 3 pin 7

//Data Pin D7 is connected to Port 2 pin 7

// Call function declarations

//This Function checks whether the LCD is ready to receive

//next byte




//This Function is used to convert Hex data to Decimal

//equivalent and write into the LCD



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}

void busy()

{D7=1;

rs=0;

rw=1;

while(D7!=0)

{

en=0;

en=1;

}

}


{

busy();

LCD_PORT=val;

rs=0;

rw=0;

en=1;

en=0;

}


{

while(*string)


}


{

busy();

LCD_PORT = ch;

rs=1;

rw=0;

en=1;

en=0;

}




// RW=1 for read




//Execute busy function to know whether the LCD is ready to receive any data/command

//Put the variable val into LCD_PORT which is connected to LCD data pins


// RW=0 for write



//increment from the beginning of the string until a


// separates a single byte from the string


//Execute busy function to know whether the LCD is ready to receive any

//data/command

//Put the variable val into LCD_PORT which is connected to LCD data pins


// RW=0 for write



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//This Function is used to convert Hex data to Decimal equivalent

//and write into the LCD

//Local variable declarations

//Local variable declarations//Local variable declarations

//Move the Hex value 'd' to a variable 'temp'

//Get the last number

//Get the 2nd last number

//Get the first number

//Concatenate all the value into a single variable

//or'ing with 0x30 will give

//the ASCII equivalent of the decimal value

//Write the 8 bit data into the LCD

//Make WR low

//nop delay

//Make WR high

//Wait for INTR to go low

//Make RD low

//Read ADC port

//Make RD high

void CONVERT_DISPLAY(unsigned char d)

{

unsigned char dig1,dig2,dig3,dig[3];

unsigned char x;unsigned char temp;

temp=d;

temp=temp/10;

dig1=d%10;

dig2=temp%10;

dig3=temp/10;

dig[0]=dig3;

dig[1]=dig2;dig[2]=dig1;

CMD_WRT(0XCA);

for(x=0;x


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www rese rchdesignl b comwww.researchdesignlab.com

10101010101010101010101010

1010101010101010101010101010101010101010101010

10100101010101010101010101010101010101010101010101010101

0 1 01 0 10 0 10 1 01 0 10 10 1 1 0 10 1 01 0 10 10 1 01 0 10

0 10 10 10 10 10 01 01 01 1 01 01 01 01 01 01 01

1 01 01 01 01 01 00 10 1 01 01 01 01 01 01 01

01 010 10 10 10 10 01 10 10 10 10 10 10 10

01 010 10 10 10 10 01 10 10 10 10 10 10 10

1 01 01 01 01 01 00 10 1 01 01 01 01 01 01 01

1 01 01 01 01 00 10 10 1 0 10 10 10 10 10 10 10 1

0 1 01 0 10 0 10 1 01 0 10 10 1 0 1 01 0 10 1 01 0 10 1 01 0 10

1010010101010101010101010101010101010101010101010101010

10101010101010101010101010101010101010101 1

1 1 101010101010101 1

010101010101010101010101010101010101

001010101010101010101010101010101010101010101010101

1 0 1 01 0 0 10 1 0 10 1 0 10 1 0 10 1 1 1 0 1 01 0 1 01 0 1 01 0 1 01 0 1 01

0 10 10 10 10 01 01 01 01 0 10 10 10 10 10 10 10 10

0 10 10 10 10 10 01 01 0 10 10 10 10 10 10 10

1 01 01 01 01 01 00 1 0 10 10 10 10 10 10 10

01 010 10 10 10 10 0 10 10 10 10 10 10 10

1 01 01 01 01 01 00 10 0 10 10 10 10 10 10 1

0 10 10 10 10 10 01 01 0 0 10 10 10 10 10 10 10

1 0 10 1 01 0 01 0 10 1 01 0 1 0 10 1 01 0 10 1 01 0 10 1 0

0101001010101010101010101 1010101010101010101010101

010101010101010101010101010101010101010101010101

1 1010101010101010101010101010101

010101010101010101010101010101

01010101010101010101010101010101010101010101010

101010010101010101010101 1 1 1 1 1010101010101010101010101

0 1 01 0 10 1 00 1 01 01 0 1 0 1 01 01 0 10 1 01 0 10 1 01

0 10 10 10 10 10 01 01 1 01 01 01 01 01 01 01

0 10 10 10 10 10 10 01 1 01 01 01 01 01 01 0

01 01 01 01 01 01 00 01 01 01 01 01 01 01

01 01 01 01 01 01 00 1 01 01 01 01 01 01 01

1 01 01 01 01 01 00 10 1 0 10 10 10 10 10 10 1

1 01 01 01 01 00 10 10 10 0 10 10 10 10 10 10 10 10

1 0 1 01 0 0 10 1 0 10 1 0 10 1 0 1 0 1 0 10 1 0 10 1 0 10 1 0 10 1 0 10 1

10010101010101010101010101010101010101010101010101

1010101010101010101010101010101010101

010101010101010

10101010101010101010101010101010101010101

010010101010101010101010101010101010101010101010101010

1 0 1 01 0 1 00 1 0 10 1 0 10 1 0 1 1 0 1 01 0 1 01 0 1 01 0 1 01 0 1 0

1 01 01 01 01 00 10 10 1 1 01 01 01 01 01 01 01 01

1 01 01 01 01 01 00 1 1 01 01 01 01 01 01 0

01 01 01 01 01 01 00 01 01 01 01 01 01 01

01 01 01 01 01 01 00 01 01 01 01 01 01 01

0 10 10 10 10 10 10 01 1 01 01 01 01 01 01 0

0 10 10 10 10 10 01 01 0 10 10 10 10 10 10 10 1

0 1 01 0 10 1 00 1 01 01 0 10 1 0 1 01 01 0 10 1 01 0 10 1 01

1010100101010101010101010101010101010101010101010101010101

101010101010101010101010101010101010101010101

1 1010101010101010101010101 1

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