LCD interface giving garbage value

[cdsanghani]

I have interface 4-bit, 16×2 LCD with PIC16F877 using hi-tech compiler. 

I have compile the code and done successfully. But in LCD display it is giving garbage value. Code is given below.

 

//LCD Control pins

 

#include<pic.h>

#include<htc.h>

#include “lcd.h”

#include<conio.h>

#include<stdio.h>

#include<string.h>

 

 

#define rs RA3

#define rw RA2

#define en RA1

//LCD Data pins

#define lcdport PORTD

 

void delayms(unsigned int);

void lcd_ini();

void dis_cmd(unsigned char);

void dis_data(unsigned char *);

void lcdcmd(unsigned char);

void lcddata(unsigned char);

 

void delayms(unsigned int a)

{

int k,j;

 

for(k=0;k<a;k++)

for(j=0;j<1175;j++);

}

 

 

void main(void)

{

unsigned char a=’x’;

// unsigned char data0[]=”hijkkj”;

char *p;

unsigned int i=0;

ADCON1=0x06;

TRISA=0;

PORTA=0;

TRISD=0; // Configure Port D as output port

PORTD=0;

delayms(5);

lcd_ini(); // LCD initialization

delayms(5);

 

p=&a;

// p=data0;

// while(data0!=’’)

 

/* while(*p!=’’)

{ dis_data(*p);

// dis_data(data0);

delayms(10);

p++;

delayms(1);

delayms(1);

}*/

 

dis_data(*p);

delayms(1000);

// dis_cmd(0x85);

// dis_data(‘b’);

 

}

void lcd_ini()                    

{

dis_cmd(0x02);     // To initialize LCD in 4-bit mode.

delayms(5);

dis_cmd(0x18); // To initialize LCD in 1 lines, 5×7 dots and 4bit mode.

delayms(5);

dis_cmd(0xF);      // Display on Cursor blinking

delayms(5);

dis_cmd(0x01); //clear screen

delayms(5);

dis_cmd(0x06);      // Entry mode

delayms(5);

dis_cmd(0x80);      // cursor position at first line

delayms(1);

delayms(1);

delayms(1);    

}

 

void dis_cmd(unsigned char cmd_value)

{

unsigned char cmd_value1;

delayms(5);

cmd_value1 = (cmd_value & 0x0F); // Mask lower nibble because RB4-RB7 pins are being used

lcdcmd(cmd_value1); // Send to LCD

delayms(5);

cmd_value1 = ((cmd_value<<4) & 0x0F); // Shift 4-bit and mask

lcdcmd(cmd_value1); // Send to LCD

delayms(5);

}

 

 

void dis_data(unsigned char *data_value)

{

 

unsigned char data_value1;

delayms(5);

data_value1=(*data_value&0x0F);

lcddata(data_value1);

delayms(5);

data_value1=((*data_value<<4)&0x0F);

lcddata(data_value1);

delayms(5);

// dis_cmd(0x14);

}

 

 

 

void lcdcmd(unsigned char cmdout)

{

lcdport=cmdout; //Send command to lcdport=PORTB

rs=0;

rw=0;

en=1;

delayms(10);

en=0;

}

 

void lcddata(unsigned char dataout)

{

lcdport=dataout; //Send data to lcdport=PORTB

rs=1;

rw=0;

en=1;

delayms(10);

en=0;

}

[AJISH ALFRED]

Hi,

Rather than using pointers and all like,

dis_data(*p);

 

Try this,

 

dis_data(‘b’);

 

If it is working then there must be some issues in your code only, otherwise check the circuit connections for any mistake.

[Ashutosh Bhatt]

for LCD interfacing on any platform there are mainly three to four functions

lcd_init()

lcd_send_command()

lcd_send_data()

lcd_print()

lcd_busy()

 

u can refer tutorials for LCD interfacing on this site.

[cdsanghani]

YA ITS OK BUT IF I WILL USE INBUILT FUCTION THEN HOW CAN I KNOW WHICH PIN OF LCD AT WHICH PORT CONECTD SO IF I WANT TO KNOW ABOUT THE FUCTION DESCRIPTION THEN HOW CAN I KNOW

[Ashutosh Bhatt]

from your code i can say you want to use header file lcd.h. 

if you are including this header file no need to write any lcd functions in code. you can just write the neame of the function with parameters. it will be called from header file. 

to see the pin details open lcd.h file in notepad. the pins are define as macro. same as you have define in your program on top.

[Author]

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