16F877a MCU and HD44870 LCD

PA3040 · Apr 12, 2013

Dear All
This is related to PIC 16F877a MCU and HD44870 LCD ( 4bit Mode)

My LCD and MCU connections are as follows.

RD4 to LCD data pin 4
RD5 to LCD data pin 5
RD6 to LCD data pin 6
RD7 to LCD data pin 7

LCD 0,1,2,3 pins are connected to GND

Code:

void lcddata(unsigned char value)
	{
LCD_RS = 1; 
LCD_DATA= (value&0xf0);
LCD_STROBE;
LCD_DATA = ((value<<4)&0xf0);
LCD_STROBE;
__delay_ms(10);
	}

Above codes data write for 4bit mode and it is working

However my new hardware design was changed as follows

RD0 to LCD data pin 4
RD1 to LCD data pin 5
RD2 to LCD data pin 6
RD3 to LCD data pin 7

Could you please advice me how may I change my above lcddata program accordant to new hardware design
Thanks in advance

Jestin_cubetech · Apr 12, 2013

LCD_DATA MSB LSB interchanged

- - - Updated - - -

Code:

void lcddata(unsigned char value)
	{
LCD_RS = 1; 

LCD_DATA= ((val>>4)&0x0F);
LCD_STROBE;
LCD_DATA =(val&0x0F); 
LCD_STROBE;

__delay_ms(10);
	}

PA3040 · Apr 12, 2013

Dear Jestin thanks for the reply

I changed as follows but still problem remaining unchanged
Please advice

Code:

void lcddata(unsigned char value)
	{
LCD_RS = 1; 
LCD_DATA= ((value>>4)&0x0f);
LCD_STROBE;
LCD_DATA = (value&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void lcdcmd(unsigned char value)
	{
LCD_RS = 0;
LCD_DATA= ((value>>4)&0x0f);
LCD_STROBE;
LCD_DATA = (value&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

Dear can you please check this program is correct

Code:

LCD_EN =0;
 __delay_us(10);  
	LCD_DATA =0X30;
     	LCD_STROBE;
       	__delay_ms(2);

       LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X30;
     	LCD_STROBE;
	__delay_ms(2);

        LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X30;
       	LCD_STROBE;
	__delay_ms(2);

       LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X20;
     	LCD_STROBE;
	__delay_ms(2);

lcdcmd(0x28);
__delay_ms(15);
lcdcmd(0x01);
__delay_ms(10);
lcdcmd(0x06);
__delay_ms(10);
lcdcmd(0x80);
__delay_ms(10);
lcdcmd(0x0c);
__delay_ms(10);

Please advice

Jestin_cubetech · Apr 12, 2013

try this lcd init

Code:

LCD_EN =0;
 __delay_us(10);  
	LCD_DATA =0X3;
     	LCD_STROBE;
       	__delay_ms(2);

       LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X3;
     	LCD_STROBE;
	__delay_ms(2);

        LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X3;
       	LCD_STROBE;
	__delay_ms(2);

       LCD_RS=0;
       __delay_us(10);  
	LCD_DATA =0X2;
     	LCD_STROBE;
	__delay_ms(2);

PA3040 · Apr 12, 2013

Dear jestin thanks for the reply

Please accept my apologize for my fault

Actually Connection could be as follows

RD0 to LCD pin 7
RD1 to LCD pin 6
RD2 to LCD pin 5
RD3 to LCD pin 4

Can you Please modify the flowing codes for above connection

Code:

void lcddata(unsigned char value)
	{
LCD_RS = 1; 
LCD_DATA= ((value>>4)&0x0f);
LCD_STROBE;
LCD_DATA = (value&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void lcdcmd(unsigned char value)
	{
LCD_RS = 0;
LCD_DATA= ((value>>4)&0x0f);
LCD_STROBE;
LCD_DATA = (value&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

Please advice
Thanks in advance

Jestin_cubetech · Apr 12, 2013

Code:

void lcd_init() 
{
       EN=0;
       LCD_RS = 0; 
       __delay_us(10);  
	LCD_DATA=0X0c;
     	ENBL;
       	__delay_ms(2);

       LCD_RS = 0; 
       __delay_us(10);  
	LCD_DATA=0X0c;
     	LCD_STROBE;
	__delay_ms(2);

         LCD_RS = 0; 
       __delay_us(10);  
	LCD_DATA=0X0c;
       	LCD_STROBE;
	__delay_ms(2);

        LCD_RS = 0; 
       __delay_us(10);  
	LCD_DATA=0X04;
     	LCD_STROBE;
	__delay_ms(2);

	lcdcmd(0X28);
	__delay_ms(5);
	lcdcmd(0X0);
	__delay_ms(5);
	lcdcmd(0X01);
	__delay_ms(5);
	lcdcmd(0X06);
	__delay_ms(5);






void lcddata(unsigned char val)
	{
//8bit reversing 

val = (val & 0x0F) << 4 | (val & 0xF0) >> 4;
val = (val & 0x33) << 2 | (val & 0xCC) >> 2;
val = (val & 0x55) << 1 | (val & 0xAA) >> 1;


LCD_RS = 1; 
LCD_DATA=(val&0x0f);
LCD_STROBE;
LCD_DATA =((val>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}


void lcdcmd(unsigned char val)
	{

//8bit reversing 
val = (val & 0x0F) << 4 | (val & 0xF0) >> 4;
val = (val & 0x33) << 2 | (val & 0xCC) >> 2;
val = (val & 0x55) << 1 | (val & 0xAA) >> 1;

LCD_RS = 0; 
LCD_DATA=(val&0x0f);
LCD_STROBE;
LCD_DATA =((val>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

PA3040 · Apr 12, 2013

Dear justing
Thanks for the reply

please see the codes and advice with wrong

Code:

#include <htc.h>
#define _XTAL_FREQ 4000000 // 4 MHz clock 

__CONFIG(0X3F39);
#define LCD_EN RC6
#define	LCD_RS RC7
#define LCD_DATA	PORTD
#define	LCD_STROBE  LCD_EN = 1; __delay_ms(1); LCD_EN=0;

unsigned char time [6] = {"Time:"};

void lcddata(unsigned char value)
	{
LCD_RS = 1; 
LCD_DATA= (value&0x0f);
LCD_STROBE;
LCD_DATA = ((value>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void lcdcmd(unsigned char value)
	{
LCD_RS = 0;
LCD_DATA= (value&0x0f);
LCD_STROBE;
LCD_DATA = ((value>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void display (){
	lcdcmd(0x80);
		for (char i=0;i<5;i++){
			lcddata(time[i]);
			
					}
		}

void lcd_init(){

TRISD	= 0;
TRISB	= 0;
TRISC   = 0;

__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);
lcdcmd(0x2);
__delay_us(10);
LCD_STROBE;
__delay_ms(2);

lcdcmd(0x28);
__delay_ms(15);
lcdcmd(0x01);
__delay_ms(10);
lcdcmd(0x06);
__delay_ms(10);
lcdcmd(0x80);
__delay_ms(10);
lcdcmd(0x0c);
__delay_ms(10);
				}

void main(){        
        lcd_init();       
			while(1){	
				display();
		
			}
}

Thanks in advance

- - - Updated - - -

Dear justing

Thanks for reply
I got the point
It was great lesson and i studied lot from you
Thanks again and again for help
PA3040

reachrajesh · Sep 25, 2013

PA3040 said:

Dear justing
Thanks for the reply

please see the codes and advice with wrong

Code:

#include <htc.h>
#define _XTAL_FREQ 4000000 // 4 MHz clock 

__CONFIG(0X3F39);
#define LCD_EN RC6
#define	LCD_RS RC7
#define LCD_DATA	PORTD
#define	LCD_STROBE  LCD_EN = 1; __delay_ms(1); LCD_EN=0;

unsigned char time [6] = {"Time:"};

void lcddata(unsigned char value)
	{
LCD_RS = 1; 
LCD_DATA= (value&0x0f);
LCD_STROBE;
LCD_DATA = ((value>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void lcdcmd(unsigned char value)
	{
LCD_RS = 0;
LCD_DATA= (value&0x0f);
LCD_STROBE;
LCD_DATA = ((value>>4)&0x0f);
LCD_STROBE;
__delay_ms(10);
	}

void display (){
	lcdcmd(0x80);
		for (char i=0;i<5;i++){
			lcddata(time[i]);
			
					}
		}

void lcd_init(){

TRISD	= 0;
TRISB	= 0;
TRISC   = 0;

__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);  
lcdcmd(0x03);
__delay_us(10);
lcdcmd(0x2);
__delay_us(10);
LCD_STROBE;
__delay_ms(2);

lcdcmd(0x28);
__delay_ms(15);
lcdcmd(0x01);
__delay_ms(10);
lcdcmd(0x06);
__delay_ms(10);
lcdcmd(0x80);
__delay_ms(10);
lcdcmd(0x0c);
__delay_ms(10);
				}

void main(){        
        lcd_init();       
			while(1){	
				display();
		
			}
}

Thanks in advance

- - - Updated - - -

Dear justing

Thanks for reply
I got the point
It was great lesson and i studied lot from you
Thanks again and again for help
PA3040

the above program is not working in proteus why?

PA3040 · Sep 25, 2013

reachrajesh said:
the above program is not working in proteus why?

Above codes two parts are missing ..what is it?

reachrajesh · Sep 26, 2013

PA3040 said:
Above codes two parts are missing ..what is it?

me too don't know i am completely new to embedded.

Venkadesh_M · Sep 26, 2013

This program is working'

PA3040 · Sep 26, 2013

reachrajesh said:
me too don't know i am completely new to embedded.

Hi

Can I have DNS file and your HEX code

reachrajesh · Sep 28, 2013

sorry for the late reply sir i got the output with the help of saeed solutions could u guide me how to get more exposure in embedded programming and guide me to use this lcd program more efficient and easier thanks in advance.

//LCD DISPLAY INTERFACING IN PIC
#include<htc.h>
#include<pic16f877a.h>

#include<string.h>
#include<stdio.h>
#define _XTAL_FREQ 20e6
__CONFIG( FOSC_HS & WDTE_OFF & PWRTE_ON & CP_OFF & BOREN_ON & LVP_OFF & CPD_OFF & WRT_OFF & DEBUG_OFF);

#define load PORTB

#define rs RC0
#define rw RC1
#define en RC2
#define gas_sensor RC3
void delayms(unsigned int);
void lcd_cmnd(unsigned char);
void lcd_data( char);
void lcd_string(const char*);
void lcd_init(void);
void main(void)
{

TRISB=0;
TRISC0=0;
TRISC1=0;
TRISC2=0;
TRISC3=0X00;
load=0X00;

TRISC3=1;
lcd_init();
lcd_cmnd(0X80);

lcd_cmnd(0X01);
lcd_cmnd(0X80);
delayms(10);
lcd_string("RAJESH");

while(1)
{

if(gas_sensor==1)
{
lcd_init();
lcd_cmnd(0X01);
lcd_string("GAS LEAKAGE IN YOUR HOME");
delayms(10);
TRISC3=1;
}

}
}
void lcd_init()
{

lcd_cmnd(0X38); // configuring LCD as 2 line 5x7 matrix
lcd_cmnd(0X0C); // Display on, Cursor blinking
lcd_cmnd(0X01); // Clear Display Screen
lcd_cmnd(0X06); // Increment Cursor (Right side)
}

void lcd_cmnd(unsigned char command)
{
load=command;
rs=0;
rw=0;
en=1;
delayms(1);
en=0;
}

void lcd_string(const char *string)
{
while(*string)
{
lcd_data(*string++);

}
}

void lcd_data(char data)
{

load=data;
rs=1;
rw=0;
en=1;
delayms(1);
en=0;

}

void delayms(unsigned int delayms)
{
unsigned int i,j;
for(i=0;i<=delayms;i++)
{
for(j=0;j<=500;j++);
}
}

16F877a MCU and HD44870 LCD

PA3040

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Jestin_cubetech

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