PROBLEM RELATED TO LCD……

[Ashish Chakole]

 HI FRIENDS,

 

i have interfaced lcd n gsm module with 89c51, everything is working fine right from the pin voltage but i m facing a different problem. according to the program lcd should immediately or with a small delay, display the required string aftre detecting an input. but whenever i give an input via any of three input pins, lcd do not show anything, but when i toch the pins of 89c51, it statrts showing the required string. i cant understant wat may b the problem. even i have checked for the loose connections, but dint get any such……

 

here i m writing my code………

also can anyone suggest me the correction in “AT Commands” given in following program, if any…….

 

Description:

if 89c51 gets an input on one of three pins, it will send a msg through gsm module also it will print corrosponding msg on LCD

 

#include<at89x51.h> // include at89x51 . h
#include<stdio.h> // include stdio . h
#include<stdlib.h> // include stdlib . h

void initialize_GSM_modem(void);
void initialize_serialcommunication(void);

unsigned int counterup = 0;
unsigned char Command_AT[]=”ATr”;
unsigned char Command_CMGF[]=”AT+CMGF=1r”;
// AT+CMGF for selecting Text Mode
unsigned char Command_CMGS[]=”AT+CMGS =9870743470r”;
// recepient mobile number
unsigned char msg02[]=”Hello!”;
unsigned char CtrlZ=0x1A;
// CTRL+Z for sedning SMS after the message has been entered

// inputs
// if any of the push button is pressed logic zero will be detected by microcontroller on respective input pin
sbit input_seal = P1^0;
sbit input_magnet = P1^1;
sbit input_reverse = P1^2;

sfr lcd_data_pin=0xA0;  // data port P2
sbit rs=P0^0; // Register select pin
sbit rw=P0^1; // Read write pin
sbit en=P0^2; // Enable pin

// outputs
// coresponding output will be generated by applying logic one on respective output pin
sbit flashing = P3^6;
sbit alarm = P3^7;

void delay(unsigned int msec)    //delay function
{
int i,j;
for(i=0;i<msec;i++)
for(j=0;j<1275;j++);
}
void lcd_command(unsigned char comm) // function to send command to LCD
{
lcd_data_pin=comm;
en=1;
rs=0;
rw=0;
delay(1);
en=0;
}
void lcd_data(unsigned char disp)    // function to send data on LCD
{
lcd_data_pin=disp;
en=1;
rs=1;
rw=0;
delay(1);
en=0;
}

lcd_dataa(unsigned char *disp)    // function to send string to LCD
{
int x;
for(x=0;disp[x]!=0;x++)
{
lcd_data(disp[x]);

}
}

void lcd_ini()     //Function to initialize the LCD
{
lcd_command(0x38);   
delay(5);
lcd_command(0x0F);       
delay(5);
lcd_command(0x80);
delay(5);
 

}

void delay2(void)
{
unsigned int i;
for(i=0;i<25000;i++);
}

void main (void)
{
P1 =0xff;
P2 = 0;
alarm = 0;
flashing = 0;
initialize_serialcommunication();
initialize_GSM_modem();

while (1)
 {
flashing =~ flashing;
delay2();

if(input_seal == 0)
{
lcd_ini();
lcd_dataa(”   Seal is    ” );
lcd_command(0x0C0);
lcd_dataa(”    broken     “);
 
alarm = 1;
puts(“Seal is Broken”);
delay2();
while(!TI);
TI = 0;
SBUF = 0x1A;
}

if(input_magnet == 0)
{
lcd_ini();
lcd_dataa(”   Magnet is  ” );
lcd_command(0x0C0);
lcd_dataa(”   detectecte  “);

alarm = 1;
puts(“Magnet is Detected”);
delay2();
while(!TI);
TI = 0;
SBUF = 0x1A;
}

if(input_reverse == 0)
{
lcd_ini();
lcd_dataa(”   Current   “);
lcd_command(0x0C0);
lcd_dataa(”   reversal   “);
 
alarm = 1;
puts(“Current reversal”);
delay2();
while(!TI);
TI = 0;
SBUF = 0x1A;
}

if(alarm == 1)
{
counterup++;
 if(counterup>=2)

{

counterup = 0; alarm = 0; P2=0;}
}
}
}

void initialize_GSM_modem(void)
{
delay2();
puts(Command_AT);
delay2();
puts(Command_CMGF);
delay2();
puts(Command_CMGS);
delay2();
puts(msg02);
delay2();
while(!TI);
TI = 0;
SBUF = 0x1A;
}

void initialize_serialcommunication(void)
{
TMOD = 0x20;
SCON = 0x50;
TH1 = 0xFD;
TL1 = 0xFD;
TR1 = 1;
TI = 1;
}

 

 

thanx

[Harsh Pandya]

This simply means that your controller pins are not properly in contact with the socket (if you are using one)

[Ashish Chakole]

thanx……….

 

[AJISH ALFRED]

What kind of power supply are you using. Always use central tapped transformer based regulated rectifier to avoid this kind of issues.

[Author]

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