[SOLVED] text Lcd (2x16) 4-bit mode with at89c52 ...... code required ?

#MAAM# · Jun 5, 2011

Hi guys

i need code for lcd with at89c52 ............. this my image of my schematic

**broken link removed**

i upload my schematic in proteus. thanks in advance.

ckshivaram · Jun 5, 2011

this is lcd.c

Code:

/************************************************************************************

Function Name   : lcd_cmdwrt()
Return value	: None       
Purpose of this function: To send the command to LCD
************************************************************************************/

void lcd_cmdwrt(unsigned char cmd)
{
	unsigned char LCD;
	LCD=((cmd & 0x0F0)>>2);
	lcd=LCD;
   	RS=0;
   	EN=1;
   	delay(1);
	EN=0;		
	LCD=((cmd & 0x0F)<<2);
	lcd=LCD;
   	RS=0;
   	EN=1;
    delay(1);
	EN=0;	
}
/************************************************************************************

Function Name   : dat()
Arguments		:data to be print on lcd
Return value	: None       
Purpose of this function: To send the data to LCD
************************************************************************************/
void dat(unsigned char dt)
{		
 	unsigned char LCD;
   		LCD=((dt & 0x0F0)>>2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay(1);  
		EN=0;
		LCD=((dt & 0x0F)<<2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay(1);
		EN=0;
		delay(1);
   		
} 
/************************************************************************************
Function Name   : lcd_datawrt()
Arguments		: String pointer of the string to be displayed
Return value	: None       
Purpose of this function: To display the string on LCD

************************************************************************************/
void lcd_datawrt(unsigned char *str)
{		
 while(*str)
  {
   dat(*str);
   str++;
  }	
}	  
/************************************************************************************
Function Name   : lcd_init()
Return value	: None       
Purpose of this function: To initialising the LCD

/************************************************************************************/
void lcd_init()
{
 	lcd_cmdwrt(0x28);
	delay(1); 	
	lcd_cmdwrt(0x0f);
	delay(1);	
	lcd_cmdwrt(0x01);
	delay(1); 	
	lcd_cmdwrt(0x06);
	delay(1); 	
	lcd_cmdwrt(0x80);
	delay(1);
}

this is lcd.h

Code:

#include<reg51.h>

/*  SFR declaration          */
sfr lcd=0x90;

/*single bit declaration */
sbit RS=0x90;            //p 1.0
sbit EN=0x91;            //p1.1          rw pin is grounded 

/* Function prototype declaration  */


/* 	LCD function decalration  */

void lcd_cmdwrt(unsigned char cmd);
void lcd_datawrt(unsigned char *);
void dat(unsigned char);
void lcd_init();
void delay(unsigned int );

the data lines are P1.2 to P1.5...

compile these 2 and check if the port pins are same...

We dont do your home work here...

modify the code for your need....

#MAAM# · Jun 5, 2011

ckshivaram said:

this is lcd.c

Code:

/************************************************************************************

Function Name   : lcd_cmdwrt()
Return value	: None       
Purpose of this function: To send the command to LCD
************************************************************************************/

void lcd_cmdwrt(unsigned char cmd)
{
	unsigned char LCD;
	LCD=((cmd & 0x0F0)>>2);
	lcd=LCD;
   	RS=0;
   	EN=1;
   	delay(1);
	EN=0;		
	LCD=((cmd & 0x0F)<<2);
	lcd=LCD;
   	RS=0;
   	EN=1;
    delay(1);
	EN=0;	
}
/************************************************************************************

Function Name   : dat()
Arguments		:data to be print on lcd
Return value	: None       
Purpose of this function: To send the data to LCD
************************************************************************************/
void dat(unsigned char dt)
{		
 	unsigned char LCD;
   		LCD=((dt & 0x0F0)>>2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay(1);  
		EN=0;
		LCD=((dt & 0x0F)<<2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay(1);
		EN=0;
		delay(1);
   		
} 
/************************************************************************************
Function Name   : lcd_datawrt()
Arguments		: String pointer of the string to be displayed
Return value	: None       
Purpose of this function: To display the string on LCD

************************************************************************************/
void lcd_datawrt(unsigned char *str)
{		
 while(*str)
  {
   dat(*str);
   str++;
  }	
}	  
/************************************************************************************
Function Name   : lcd_init()
Return value	: None       
Purpose of this function: To initialising the LCD

/************************************************************************************/
void lcd_init()
{
 	lcd_cmdwrt(0x28);
	delay(1); 	
	lcd_cmdwrt(0x0f);
	delay(1);	
	lcd_cmdwrt(0x01);
	delay(1); 	
	lcd_cmdwrt(0x06);
	delay(1); 	
	lcd_cmdwrt(0x80);
	delay(1);
}

this is lcd.h

Code:

#include<reg51.h>

/*  SFR declaration          */
sfr lcd=0x90;

/*single bit declaration */
sbit RS=0x90;            //p 1.0
sbit EN=0x91;            //p1.1          rw pin is grounded 

/* Function prototype declaration  */


/* 	LCD function decalration  */

void lcd_cmdwrt(unsigned char cmd);
void lcd_datawrt(unsigned char *);
void dat(unsigned char);
void lcd_init();
void delay(unsigned int );

the data lines are P1.2 to P1.5...

compile these 2 and check if the port pins are same...

thanks for your support. but it`s still not working !!!!!!!!!!!!!!!!!!

my code

basic calculator.c

Code:

#include <reg52.h>
#include "lcd.h"

main( )
{	while(1)
    {lcd_init();
	lcd_datawrt("Hello");
     }
}

/************************************************************************************

Function Name   : lcd_cmdwrt()
Return value	: None       
Purpose of this function: To send the command to LCD
************************************************************************************/

void lcd_cmdwrt(unsigned char cmd)
{
	unsigned char LCD;
	LCD=((cmd & 0x0F0)>>2);
	lcd=LCD;
   	RS=0;
   	EN=1;
   	delay();
	EN=0;		
	LCD=((cmd & 0x0F)<<2);
	lcd=LCD;
   	RS=0;
   	EN=1;
    delay();
	EN=0;	
}
/************************************************************************************

Function Name   : dat()
Arguments		:data to be print on lcd
Return value	: None       
Purpose of this function: To send the data to LCD
************************************************************************************/
void dat(unsigned char dt)
{		
 	unsigned char LCD;
   		LCD=((dt & 0x0F0)>>2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay();  
		EN=0;
		LCD=((dt & 0x0F)<<2);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay();
		EN=0;
		delay();
   		
} 
/************************************************************************************
Function Name   : lcd_datawrt()
Arguments		: String pointer of the string to be displayed
Return value	: None       
Purpose of this function: To display the string on LCD

************************************************************************************/
void lcd_datawrt(unsigned char *str)
{		
 while(*str)
  {
   dat(*str);
   str++;
  }	
}	  
/************************************************************************************
Function Name   : lcd_init()
Return value	: None       
Purpose of this function: To initialising the LCD

/************************************************************************************/
void lcd_init()
{
 	lcd_cmdwrt(0x28);
	delay(); 	
	lcd_cmdwrt(0x0f);
	delay();	
	lcd_cmdwrt(0x01);
	delay(); 	
	lcd_cmdwrt(0x06);
	delay(); 	
	lcd_cmdwrt(0x80);
	delay();
}

void delay()
{
	unsigned char i;
	for (i=0; i<500 ;i++);	
}

lcd.h

Code:

#include<reg52.h>

/*  SFR declaration          */
sfr lcd=0x80;

/*single bit declaration */
sbit RS=0x80;            //p 0.0
sbit EN=0x82;            //p0.2          rw pin is grounded 

/* Function prototype declaration  */


/* 	LCD function decalration  */

void lcd_cmdwrt(unsigned char cmd);
void lcd_datawrt(unsigned char *);
void dat(unsigned char);
void lcd_init();
void delay();

i upload my files including firmware with keil c and proteus file

FvM · Jun 5, 2011

I see two versions of basic calculator main.c, one in the archive and the text posted in the recent mail. None of them corresponds to the actual pin assignment. The archive version has 8-bit port access which is obviously wrong. And the last code simply copies the code dedicated for bit2..5 LCD port, as posted by ckshivaram. But you have bit4..7 instead.

#MAAM# · Jun 5, 2011

FvM said:
I see two versions of basic calculator main.c, one in the archive and the text posted in the recent mail. None of them corresponds to the actual pin assignment. The archive version has 8-bit port access which is obviously wrong. And the last code simply copies the code dedicated for bit2..5 LCD port, as posted by ckshivaram. But you have bit4..7 instead.

how can i chose the actual pin assignment ?

FvM · Jun 5, 2011

The data shift should change to the below code to access bit4..7

Code:

LCD= (dt & 0x0F0);
lcd=LCD;
RS=1;
EN=1;
delay();  
EN=0;
LCD=((dt & 0x0F)<<4);

I hope, the code can work after these changes. There are however some weaknesses involved with the code.
- The init code will depend on a previous hardware reset (e.g. power on reset) of the LCD controller. It won't work, if the controller state has been messed up somehow. In this case the more complex "Initializing by Instruction" procedure would required, refer to the HD44780 datasheet.
- The display timing is ineffective by applying rather long delays for each write. Using optimized timing and checking LCD busy flag would considerably speed it up.

It should be also noted, that writing to the lcd data port (P0) implicitely resets all LCD control lines as well. But it's no problem with the present code.

#MAAM# · Jun 6, 2011

FvM said:
The data shift should change to the below code to access bit4..7

Code:

LCD= (dt & 0x0F0); lcd=LCD; RS=1; EN=1; delay(); EN=0; LCD=((dt & 0x0F)<<4);

I hope, the code can work after these changes. There are however some weaknesses involved with the code.
- The init code will depend on a previous hardware reset (e.g. power on reset) of the LCD controller. It won't work, if the controller state has been messed up somehow. In this case the more complex "Initializing by Instruction" procedure would required, refer to the HD44780 datasheet.
- The display timing is ineffective by applying rather long delays for each write. Using optimized timing and checking LCD busy flag would considerably speed it up.

It should be also noted, that writing to the lcd data port (P0) implicitely resets all LCD control lines as well. But it's no problem with the present code.

thanks for your support. code is working with me now very well.

#MAAM# · Jun 6, 2011

thanks to every body help me

my working code
basic calculator.c

Code:

#include <reg52.h>
#include "lcd.h"

main( )
{	
    lcd_init();
	lcd_datawrt("Hello");
    while(1);
}

/************************************************************************************

Function Name   : lcd_cmdwrt()
Return value	: None       
Purpose of this function: To send the command to LCD
************************************************************************************/

void lcd_cmdwrt(unsigned char cmd)
{
	unsigned char LCD;
	LCD=(cmd & 0x0F0);
	lcd=LCD;
   	RS=0;
   	EN=1;
   	delay();
	EN=0;		
	LCD=((cmd & 0x0F)<<4);
	lcd=LCD;
   	RS=0;
   	EN=1;
    delay();
	EN=0;	
}
/************************************************************************************

Function Name   : dat()
Arguments		:data to be print on lcd
Return value	: None       
Purpose of this function: To send the data to LCD
************************************************************************************/
void dat(unsigned char dt)
{		
 	unsigned char LCD;
   		LCD=(dt & 0x0F0);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay();  
		EN=0;
		LCD=((dt & 0x0F)<<4);
		lcd=LCD;
   		RS=1;
   		EN=1;
   		delay();
		EN=0;
		delay();
   		
} 
/************************************************************************************
Function Name   : lcd_datawrt()
Arguments		: String pointer of the string to be displayed
Return value	: None       
Purpose of this function: To display the string on LCD

************************************************************************************/
void lcd_datawrt(unsigned char *str)
{		
 while(*str)
  {
   dat(*str);
   str++;
  }	
}	  
/************************************************************************************
Function Name   : lcd_init()
Return value	: None       
Purpose of this function: To initialising the LCD

/************************************************************************************/
void lcd_init()
{
 	lcd_cmdwrt(0x28);
	delay(); 	
	lcd_cmdwrt(0x0f);
	delay();	
	lcd_cmdwrt(0x01);
	delay(); 	
	lcd_cmdwrt(0x06);
	delay(); 	
	lcd_cmdwrt(0x80);
	delay();
}

void delay()
{
	unsigned char i;
	for (i=0; i<200;i++);	
}

lcd.h

Code:

#include<reg52.h>

/*  SFR declaration          */
sfr lcd=0x80;

/*single bit declaration */
sbit RS=0x80;            //p 0.0
sbit EN=0x81;            //p0.2          rw pin is grounded 

/* Function prototype declaration  */


/* 	LCD function decalration  */

void lcd_cmdwrt(unsigned char cmd);
void lcd_datawrt(unsigned char *);
void dat(unsigned char);
void lcd_init();
void delay();

i also upload my working code and proteus simulation file .

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[SOLVED] text Lcd (2x16) 4-bit mode with at89c52 ...... code required ?

#MAAM#

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ckshivaram

Advanced Member level 6

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FvM

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