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Interfacing JHD162 LCD with ATMEGA8

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Nicole575

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I made a simple circuit to interface 16X2 LCD with atmega8 micro-controller.Everything seems to work fine but when i tried to display a text in second line of the LCD, i get nothing.The text doesn't get displayed. I believe I've send proper command and all but still i don't get anything displayed in the second line. Then i tried to display a single character in the middle portion of the first line and same thing happens here.Nothing gets displayed.The cursor seems to appear but the text doesn't.
Here is the code.


Code C - [expand]
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/*
 * LCD_interfacing_along_with_UI.c
 *
 * Created: 8/12/2015 3:42:05 PM
 *  Author: Aastha
 */ 
 
 
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
 
 
/* All the macro definitions related to LCD */
#define RS      PB0
#define RW      PB1
#define E       PB2
#define SW_1_SELECT PC0
#define SW_2_UP     PC1
#define SW_3_DOWN   PC2
#define SW_4_LEFT   PC3
#define SW_5_RIGHT  PC4
#define data    PORTD
#define SET_RS()    (PORTB|=(1<<RS))     
#define SET_RW()    (PORTB|=(1<<RW))
#define SET_E()     (PORTB|=(1<<E))
#define RESET_RS()  (PORTB&=~(1<<RS))
#define RESET_RW()  (PORTB&=~(1<<RW))
#define RESET_E()   (PORTB&=~(1<<E))
void initalize_lcd(unsigned char cmd1,unsigned char cmd2,unsigned char cmd3);
void lcd_busy(void);
void write_string( char *str);
void write_data(unsigned char datas);
void send_command(unsigned char cmd);
void display_multiple_options(void);
 
 
int main(void)
{
    DDRD=0b11111111;            //making PORTD as output port for data
    DDRB=0b00000111;            //making PORTB for control signals
    DDRC=0b0000000;             //making PORTC as input port for switches
    PORTC=0b1111111;
    initalize_lcd(0x38,0x01,0x0E);
    _delay_ms(50);
    send_command(0xC5);
    _delay_ms(50);
    write_string("GUITAR");
    _delay_ms(1000);
    /*initalize_lcd(0x30,0x01,0x0E);
    send_command(0xC0);*/
   
    while(1)
    {
        /*if(bit_is_clear(PINC,SW_1_SELECT))
        {
            display_multiple_options();
            break;
            /*if(bit_is_clear(PINC,SW_2_UP))
            {
                
            }
            else if(bit_is_clear(PINC,SW_3_DOWN))
            {
                
            }
            else if(bit_is_clear(PINC,SW_4_LEFT))
            {
                
            }
            else if(bit_is_clear(PINC,SW_5_RIGHT))
            {
                
            }
            else
            {
                
            }
            
        }           
        else
        {
            
            
         write_string("...PRESS SELECT BUTTON ");
            _delay_ms(1000);
         send_command(0x18);
                 
        }        
 
    }
    
    return 0;*/
    }
}   
void initalize_lcd(unsigned char cmd1,unsigned char cmd2,unsigned char cmd3)
{
    send_command(cmd1);     //to display content in one/two line in 5x7 matrix
    _delay_ms(1);           
    send_command(cmd2);     //clearing the display including/not including RAM data
    _delay_ms(1);
    send_command(cmd3);     //making cursor and display on
    _delay_ms(1);
    
}
void send_command(unsigned char cmd)
{
    lcd_busy();
    data=cmd;
    SET_E();        //setting the enable to latch data to data lines of LCD
    RESET_RS();     //resetting register select to choose command register
    RESET_RW();     //resetting R/W to write commands to data lines of LCD
    _delay_ms(50);
    RESET_E();      //resetting enable to send data to LCD
    _delay_ms(50);
}
void write_string( char *str)
{
    int i=0;
    while(str[i]!='\0')
    {
        write_data(str[i]);
        i++;
    }
}
void write_data(unsigned char datas)
{
    lcd_busy();
    data=datas;
    SET_E();
    RESET_RW();
    SET_RS();
    _delay_ms(1);
    RESET_E();
}
void lcd_busy()
{
    DDRD=0b00000000;
    RESET_RS();      //resetting RS to select command register
    SET_RW();       //setting RW to read from LCD to micro controller
    while(PORTD>=0x80)      // when pin PD7 is 1 the LCD is busy
    {
        SET_E();
        _delay_ms(1);
        RESET_E();
    }
    DDRD=0b11111111;
    
}
/*void display_multiple_options()
{
    initalize_lcd(0X38,0x01,0x0E);
    _delay_ms(50);
    send_command(0X85);
    _delay_ms(1);
    write_string("GUITAR");
    send_command(0xC0);
    _delay_ms(1);
    write_string("AA");
    _delay_ms(100);
}*/

 
Last edited by a moderator:

Hi,

Most of the displays have an offset in the addres to the second line.
Please read datasheet.

Klaus
 
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