[SOLVED] problem with my 16x2 LCD

Dilpreet Singh · Feb 16, 2015

i write a code for jhd-16 * 2 lcd it is working on protious but not on hardware ?
i give about 50 ms delay after each command even it is not working with such a big delay

Easyrider83 · Feb 16, 2015

Should we imagine you code somehow?

Debasis Swain · Feb 16, 2015

Show your code

Dilpreet Singh · Feb 16, 2015

Code C - [expand]
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#include <avr/io.h>
#include <avr/delay.h>
#include <util/delay.h>
 
#define RS 0
#define RW 1
#define EN 2
#define lcd_port PORTD
 
#define F_CPU 11592000ul
 
 
 
#define sbit(reg,bit)   reg |= (1<<bit)
#define cbit(reg,bit)   reg &= ~(1<<bit)
 
void init_ports();
void lcd_set_4bit();
void lcd_init();
void lcd_wr_command(unsigned char);
void lcd_wr_char(char);
void lcd_home();
void lcd_cursor(char, char);
void lcd_print(char, char, unsigned int, int);
void lcd_string(char*);
 
unsigned int temp;
unsigned int unit;
unsigned int tens;
unsigned int hundred;
unsigned int thousand;
unsigned int million;
 
 
 
/*****Function to Reset LCD*****/
void lcd_set_4bit()
{
    _delay_ms(1);
 
    cbit(lcd_port,RS);              //RS=0 --- Command Input
    cbit(lcd_port,RW);              //RW=0 --- Writing to LCD
    _delay_ms(10);   
     lcd_port = 0x30;               //Sending 3
    _delay_ms(100); 
 
 
    sbit(lcd_port,EN);              //Set Enable Pin
    
    _delay_ms(20);                  //Delay
 
   
    cbit(lcd_port,EN);              //Clear Enable Pin
 
    _delay_ms(10);
 
    cbit(lcd_port,RS);              //RS=0 --- Command Input
    cbit(lcd_port,RW);              //RW=0 --- Writing to LCD
_delay_ms(100); 
    lcd_port = 0x30;                //Sending 3
_delay_ms(100);
 
    sbit(lcd_port,EN);              //Set Enable Pin
 
    _delay_ms(20);                  //Delay
    cbit(lcd_port,EN);              //Clear Enable Pin
 
    _delay_ms(10);
 
    cbit(lcd_port,RS);              //RS=0 --- Command Input
    cbit(lcd_port,RW);              //RW=0 --- Writing to LCD
 
 
    lcd_port = 0x30;                //Sending 3
_delay_ms(100);
    sbit(lcd_port,EN);              //Set Enable Pin
 
    _delay_ms(20);                  //Delay
    cbit(lcd_port,EN);              //Clear Enable Pin
 
    _delay_ms(10);
 
    cbit(lcd_port,RS);              //RS=0 --- Command Input
    cbit(lcd_port,RW);              //RW=0 --- Writing to LCD
 
    lcd_port = 0x20;                //Sending 2 to initialise LCD 4-bit mode
_delay_ms(100);
    sbit(lcd_port,EN);              //Set Enable Pin
 
 
    _delay_ms(20);                  //Delay
    cbit(lcd_port,EN);              //Clear Enable Pin
 
    
}
 
/*****Function to Initialize LCD*****/
void lcd_init()
{
    _delay_ms(10);
 
    lcd_wr_command(0x28);           //LCD 4-bit mode and 2 lines.
    _delay_ms(100);
    lcd_wr_command(0x01);
    _delay_ms(100);
    lcd_wr_command(0x06);
    
    _delay_ms(100);
    lcd_wr_command(0x0E);
    _delay_ms(100);
    lcd_wr_command(0x80);
    _delay_ms(100); 
}
 
     
/*****Function to Write Command on LCD*****/
void lcd_wr_command(unsigned char cmd)
{
    unsigned char temp;
    temp = cmd;
    temp = temp & 0xF0;
    lcd_port &= 0x0F;
    _delay_ms(100);
    lcd_port |= temp;
    _delay_ms(100);
    cbit(lcd_port,RS);
    cbit(lcd_port,RW);
    sbit(lcd_port,EN);
    _delay_ms(100);
    _delay_ms(5);
    cbit(lcd_port,EN);
    
    cmd = cmd & 0x0F;
    cmd = cmd<<4;
    lcd_port &= 0x0F;
    lcd_port |= cmd;
    _delay_ms(100);
    cbit(lcd_port,RS);
    cbit(lcd_port,RW);
    sbit(lcd_port,EN);
    
    _delay_ms(5);
    cbit(lcd_port,EN);
 
}
 
/*****Function to Write Data on LCD*****/
void lcd_wr_char(char letter)
{
    char temp;
    temp = letter;
    temp = (temp & 0xF0);
    lcd_port &= 0x0F;
    lcd_port |= temp;
_delay_ms(100);
    sbit(lcd_port,RS);
    cbit(lcd_port,RW);
    sbit(lcd_port,EN);
 
 
    _delay_ms(5);
    cbit(lcd_port,EN);
 
    letter = letter & 0x0F;
    letter = letter<<4;
    lcd_port &= 0x0F;
    lcd_port |= letter;
_delay_ms(100);
    sbit(lcd_port,RS);
    cbit(lcd_port,RW);
    sbit(lcd_port,EN);
 
    _delay_ms(20);
    cbit(lcd_port,EN);
 
}
 
 
void lcd_home()
{
    lcd_wr_command(0x80);
}
 
 
/*****Function to Print String on LCD*****/
void lcd_string(char *str)
{
    while(*str != '\0')
    {
        lcd_wr_char(*str);
        str++;
    _delay_ms(100);
    }
}
 
/*** Position the LCD cursor at "row", "column". ***/
 
void lcd_cursor (char row, char column)
{
    switch (row) {
        case 1: lcd_wr_command (0x80 + column - 1); break;
        case 2: lcd_wr_command (0xc0 + column - 1); break;
        case 3: lcd_wr_command (0x94 + column - 1); break;
        case 4: lcd_wr_command (0xd4 + column - 1); break;
        default: break;
    }
}
 
/***** Function To Print Any input value upto the desired digit on LCD *****/
void lcd_print (char row, char coloumn, unsigned int value, int digits)
{
    unsigned char flag=0;
    if(row==0||coloumn==0)
    {
        lcd_home();
    _delay_ms(100);
    }
    else
    {
        lcd_cursor(row,coloumn);
    }
    if(digits==5 || flag==1)
    {
        million=value/10000+48;
        lcd_wr_char(million);
        flag=1;
    }
    if(digits==4 || flag==1)
    {
        temp = value/1000;
        thousand = temp%10 + 48;
        lcd_wr_char(thousand);
        flag=1;
    }
    if(digits==3 || flag==1)
    {
        temp = value/100;
        hundred = temp%10 + 48;
        lcd_wr_char(hundred);
        flag=1;
    }
    if(digits==2 || flag==1)
    {
        temp = value/10;
        tens = temp%10 + 48;
        lcd_wr_char(tens);
        flag=1;
    }
    if(digits==1 || flag==1)
    {
        unit = value%10 + 48;
        lcd_wr_char(unit);
    }
    if(digits>5)
    {
        lcd_wr_char('E');
    }
    
}
        
int main()
 
{
DDRD=0b11111111;
 
lcd_init();
lcd_set_4bit();
 
 
 
int a=43;
while(1){
_delay_ms(200);
 
 
lcd_string("123456789 ");
 
}
 
 
 
}

MUKESH.K.S · Feb 16, 2015

Show your circuit . Have you connected 10k pot to VEE pin to adjust contrast.

Dilpreet Singh · Feb 16, 2015

i connect 10k pot to VEE , earlier it was shorted with vcc ,
but still not working

Ogu Reginald · Feb 16, 2015

The first time I used the said LCD, after writing my code I simulated it using proteus and it was working as designed but when I constructed the hardware, it was not working.
I abandoned the project on my desk but I was doing something: every morning if I woke up I will go straight to the table and troubleshoot my connections and every night before I slept, I did the same thing.
One day I just discovered that melted lead alloy (for soldering) went and shorted three pins (EN, RS, RW). Immediately I seperated the three pins every thing worked well.

My advice for you since you have simulated your design virtually and it is working, make sure that all connections are the way they ought to be and check your delay function to see whether the delay is sufficient to be noticed in real life.

Dilpreet Singh · Feb 16, 2015

i check connections and increase delay about 1 sec now , but not working yet

milan.rajik · Feb 16, 2015

Try this code. I have not tested it.

Code C - [expand]
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/*
 * LCD_4_bit.c
 *
 * Created: 2/17/2015 1:04:20 AM
 *  Author: Jayanth Devarayanadurga
 */ 
 
#define F_CPU 400000
 
#include <avr/io.h>
#include <util/delay.h>
#include <string.h>
 
#define _LCD_FIRST_ROW          0x80     //Move cursor to the 1st row
#define _LCD_SECOND_ROW         0xC0     //Move cursor to the 2nd row
#define _LCD_THIRD_ROW          0x94     //Move cursor to the 3rd row
#define _LCD_FOURTH_ROW         0xD4     //Move cursor to the 4th row
#define _LCD_CLEAR              0x01     //Clear display
#define _LCD_RETURN_HOME        0x02     //Return cursor to home position, returns a shifted display to
                                         //its original position. Display data RAM is unaffected.
#define _LCD_CURSOR_OFF         0x0C     //Turn off cursor
#define _LCD_UNDERLINE_ON       0x0E     //Underline cursor on
#define _LCD_BLINK_CURSOR_ON    0x0F     //Blink cursor on
#define _LCD_MOVE_CURSOR_LEFT   0x10     //Move cursor left without changing display data RAM
#define _LCD_MOVE_CURSOR_RIGHT  0x14     //Move cursor right without changing display data RAM
#define _LCD_TURN_ON            0x0C     //Turn Lcd display on
#define _LCD_TURN_OFF           0x08     //Turn Lcd display off
#define _LCD_SHIFT_LEFT         0x18     //Shift display left without changing display data RAM
#define _LCD_SHIFT_RIGHT        0x1E     //Shift display right without changing display data RAM
 
#define RS 0
#define EN 2
#define LCD_PORT PORTD
 
#define sbit(reg,bit)   reg |= (1<<bit)
#define cbit(reg,bit)   reg &= ~(1<<bit)
 
void LCD_Init();
void LCD_Cmd(char);
void LCD_Chr(char, char, char);
void LCD_Chr_Cp(char);
void LCD_Out(char, char, char*);
void LCD_Out_Cp(char*);
 
void lcd_print(char, char, unsigned int, int);
 
void LCD_Init() {
 
    _delay_ms(100);
    
    cbit(LCD_PORT,RS);              //RS=0 --- Command Input
        
    LCD_PORT = 0x30;               //Sending 3
    sbit(LCD_PORT,EN);              //Set Enable Pin
    _delay_us(50);                  //Delay
    cbit(LCD_PORT,EN);              //Clear Enable Pin
    
    _delay_ms(30);
        
    LCD_PORT = 0x30;               //Sending 3
    sbit(LCD_PORT,EN);              //Set Enable Pin
    _delay_us(50);                  //Delay
    cbit(LCD_PORT,EN);              //Clear Enable Pin
    
    _delay_ms(30);             //Clear Enable Pin
            
    LCD_PORT = 0x30;               //Sending 3
    sbit(LCD_PORT,EN);              //Set Enable Pin
    _delay_us(50);                 //Delay
    cbit(LCD_PORT,EN);              //Clear Enable Pin
    
    _delay_ms(30);            //Clear Enable Pin
            
    LCD_PORT = 0x20;               //Sending 3
    sbit(LCD_PORT,EN);              //Set Enable Pin
    _delay_us(50);                  //Delay
    cbit(LCD_PORT,EN);              //Clear Enable Pin
    
    _delay_ms(30);             //Clear Enable Pin
    
    LCD_Cmd(0x28);
    LCD_Cmd(0x0C);  
}
 
void LCD_Cmd(char out_char) {       
    cbit(LCD_PORT,RS);
        
    LCD_PORT = out_char & 0xF0;
        
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);
    
    LCD_PORT = (out_char & 0x0F) << 4;
    
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);  
}
 
void LCD_Chr(char row, char column, char out_char) {
    
    switch (row) {
        case 1: LCD_Cmd (0x80 + column - 1); break;
        case 2: LCD_Cmd (0xc0 + column - 1); break;
        case 3: LCD_Cmd (0x94 + column - 1); break;
        case 4: LCD_Cmd (0xD4 + column - 1); break;     
    };
        
    sbit(LCD_PORT,RS);  
        
    LCD_PORT = out_char & 0xF0;
    
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);
    
    LCD_PORT = (out_char & 0x0F) << 4;
    
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);  
}
 
void LCD_Chr_Cp(char out_char) {
    
    sbit(LCD_PORT,RS);
    
    LCD_PORT = out_char & 0xF0;
    
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);
    
    LCD_PORT = (out_char & 0x0F) << 4;
    
    sbit(LCD_PORT,EN);
    _delay_us(50);
    cbit(LCD_PORT,EN);
}
 
void LCD_Out(char row, char column, char *str) {
    while(*str)
        LCD_Chr(row, column, *str++);   
}
 
void LCD_Out_Cp(char *str) {
    while(*str)
        LCD_Chr_Cp(*str++);
}
 
int myInt = 255;
char str[17];
 
int main() {
 
    DDRD = 0b11111111;
    PORTD = 0x00;
    
    LCD_Init();
    LCD_Cmd(_LCD_CURSOR_OFF);
    LCD_Cmd(_LCD_CLEAR);    
    
    LCD_Out(1,1,"ATMega32");
    LCD_Out(2,1,"LCD 4 bit");
    LCD_Out(3,1,"16x2, 20x2, 20x4");
    LCD_Out(4,1,"Testing...");
    
    _delay_ms(5000);
    LCD_Cmd(_LCD_CLEAR);    
    
    itoa(myInt, str, 10);
    LCD_Out(1,1,str);
    
    while(1){
                    
    }   
}

Dilpreet Singh · Feb 16, 2015

Sry , this code is not working...

milan.rajik · Feb 16, 2015

Which MCU are you using ?

Dilpreet Singh · Feb 16, 2015

atmega8 Sir ....

- - - Updated - - -

And is there is a need to gnd the remaing 4 data pins which are unused ? ie D0 to D3 Of LCD

milan.rajik · Feb 16, 2015

No, no need to ground them.

Dilpreet Singh · Feb 16, 2015

so sir what is problem ?

Ogu Reginald · Feb 17, 2015

www.8051projects.net/lcd-interfacing/lcd-4-bit.php

- - - Updated - - -

www.8051projects.net/lcd-interfacing/lcd-4-bit.php

- - - Updated - - -

https://learningmsp430.wordpress.com/2013/11/16/16x2-lcd-interfacing-in-4-bit-mode/

ud23 · Feb 17, 2015

Dilpreet Singh said:
so sir what is problem ?

I don't see any initialization for command pins like EN,RS,RW in your posted code. And i normally test any hardware with just basic functions first then go to the whole functionality or application.

https://extremeelectronics.co.in/avr-tutorials/using-lcd-module-with-avrs/

Dilpreet Singh · Feb 17, 2015

yes there is problem with delays as well as with potentiometer , Now it is solved
THANKS EVERY ONE

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