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8051 lcd interfacing problem

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hashim5003

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I am interfacing at89s52 with 16*2 lcd. Problem is that lcd don't shows the character that I have written in the code. it shows some random character or weird character. Plz chk my code if it's correct or not:

Code: 
#include<reg52.h>
sfr ldata=0x90;  
sbit rs=P3^7; 
sbit rw=P3^6; 
sbit en=P3^5;

void delay()
{
	TMOD = 0x01;
	TH0 = 0x00;
	TL0 = 0x00;
	TR0 = 1;
	while (TF0==0);
	TF0 = 0;
	TR0 = 0;
}

void lcdcmd(unsigned char u)
{
	ldata=u;
	en=1;
	rs=0;
	rw=0;
	delay();
	en=0;
	delay();
}
void lcddata(unsigned char v)    
{
	ldata=v;
	en=1;
	rs=1;
	rw=0;
	delay();
	en=0;
}

void lcdini()    
{
	delay();
	lcdcmd(0x30);
	delay();
	delay();
	lcdcmd(0x30);
	delay();
	delay();
	lcdcmd(0x30);
	delay();
	lcdcmd(0x38);   
	delay();
	lcdcmd(0x0c);       
	delay();
	lcdcmd(0x80);
	delay();

}
void main()
{
	lcdini();

	lcddata('A');
	delay();
	lcddata('B');
	delay();
	lcddata('C');
	delay();

	while(1);
}
 

I don't know C language because i am an assembly language programmer but in your code i didn't see the busy flag checking before initialization of the lcd.......First of all you should check the busy flag or give a delay of about 20ms before issuing any command...
 

HI hashim
apply the following changes to your code
Code: 
void delay(unsigned int ms)  //This I have added you may use your own delay 
{
int i , j
for(i=0 ; i<ms ; i++)
{
for(j = 0 ; j<1275 ; j++);
}
}void LCD_init()
{
lcdcmd(0x38);    // Initialize 2 lines 5*7    
lcdcmd(0x0C ) ;  //Cursor OFF
lcdcmd(0x01) ;   
lcdcmd(0x06) ; 
lcdcmd(0x80) ; 
}
void lcddata(unisgned char data)
{  ladata = data ;  RS = 1 ; RW = 0 ; EN = 1 ; delay(5) ; EN = 0 ;}
void lcdcmd(unsigned char cmd)
{ ldata = data ; RS = 0 ; RW = 0 ; EN =1 ; delay(5) ; EN = 0 ; }
void main()
{
ladta = 0x00 ;   // Making the PORT as Output which is connected with Data Lines of LCD

//rs = 1 ; rw = 1 ; en = 1 ; 
// Also make the pins as OUTPUT which are connected to RS , RW and Enable Pins

LCD_init() ; 
delay(1000);
lcddata('A'); delay(100); lcddata('B'); 
}
 
Last edited:

embRTS said:
HI hashim
apply the following changes to your code
Code: 
void delay(unsigned int ms)  //This I have added you may use your own delay 
{
int i , j
for(i=0 ; i<ms ; i++)
{
for(j = 0 ; j<1275 ; j++);
}
}void LCD_init()
{
lcdcmd(0x38);    // Initialize 2 lines 5*7    
lcdcmd(0x0C ) ;  //Cursor OFF
lcdcmd(0x01) ;   
lcdcmd(0x06) ; 
lcdcmd(0x80) ; 
}
void lcddata(unisgned char data)
{  ladata = data ;  RS = 1 ; RW = 0 ; EN = 1 ; delay(5) ; EN = 0 ;}
void lcdcmd(unsigned char cmd)
{ ldata = data ; RS = 0 ; RW = 0 ; EN =1 ; delay(5) ; EN = 0 ; }
void main()
{
ladta = 0x00 ;   // Making the PORT as Output which is connected with Data Lines of LCD

//rs = 1 ; rw = 1 ; en = 1 ; 
// Also make the pins as OUTPUT which are connected to RS , RW and Enable Pins

LCD_init() ; 
delay(1000);
lcddata('A'); delay(100); lcddata('B'); 
}
Click to expand...

Tried it. still no difference. showing random characters

- - - Updated - - -

one thing i have noticed is that when I power up controller and lcd. it shows correctly for some time and then shows some random character
 

Apply some delay before each command as JAMLAL also said
like
Code: 
void LCD_init()
{
lcdcmd(0x38);    // Initialize 2 lines 5*7    
delay(100);  //Try with 20 or 30
lcdcmd(0x0C ) ;  //Cursor OFF
delay(100);
lcdcmd(0x01) ; delay(100);   
lcdcmd(0x06) ;  delay(100);
lcdcmd(0x80) ; delay(100);
}
Also Upload any Image if you have of the same if still it is not working
 

embRTS said:
Apply some delay before each command as JAMLAL also said
like
Code: 
void LCD_init()
{
lcdcmd(0x38);    // Initialize 2 lines 5*7    
delay(100);  //Try with 20 or 30
lcdcmd(0x0C ) ;  //Cursor OFF
delay(100);
lcdcmd(0x01) ; delay(100);   
lcdcmd(0x06) ;  delay(100);
lcdcmd(0x80) ; delay(100);
}
Also Upload any Image if you have of the same if still it is not working
Click to expand...


I will take the image tomorrow.
i have used delays.
could it be the problem of lcd hardware?
 

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