[SOLVED] Initializing LCD ST7920 ?

[bianchi77]

Guys,

I tried to display message on ST7920 LCD,
It's displaying the text already, but I must reset few times before it can display properly,

Do I miss something here ?

Here's the code I used :

char menu_txt[21] = " ATMEGA128    "; 
void lcd_init(){
    //st7920
		lcd_cmd(0x30);
		_delay_ms(100);
		lcd_cmd(0x30);
		_delay_ms(100);
		lcd_cmd(0x0F);
		_delay_ms(100);
		//lcd_cmd(0x80);
		//_delay_ms(10);
		lcd_cmd(0x01); //clear screen
		_delay_ms(100);
		lcd_cmd(0x02);//Return home
		_delay_ms(100);

		lcd_cmd(0x06);//cursor to the right
		_delay_ms(100);
		    

   
	
}


void lcd_data(unsigned char data1)
{
	
	
	lcd_data_pin = data1;// & 0x0F;
	en=1;
    _delay_us(100);
	rs=1;
   _delay_us(100);
	rw=0;
	_delay_ms(10);
	en=0;
	
}

void lcd_cmd(unsigned char cmd){
	
	lcd_data_pin = cmd ;
	_delay_us(100);
	en=1;
    _delay_us(100);
	rs=0;
    _delay_us(100);
	rw=0;

	_delay_ms(10);
	en=0;
	
	
	
}



void lcd_string(unsigned char *str){
	
	while(*str){
		lcd_data(*str++);
	}
	
}

lcd_string(menu_txt);

Any ideas ?
thanks

 

[embRTS]

Try this Function for initialization

void LCD_init()
{
delay(100);
	LCD_cmd(0x38);		// or 0x30 as you have mentioned
	LCD_cmd(0x0C);		// You Can Write 0x0E also but It will show the Cursor
	LCD_cmd(0x01);         //Clear Display
	LCD_cmd(0x06);        //Entry Mode from  Left To Right 
	LCD_cmd(0x80);       //1st Row , 1st Column
}
void LCD_cmd(unsigned char command)
{
command = LCD_DATA ;  delay(50) ;  RS = 0 ; RW = 0 ; EN=1 delay(5); EN = 0 ; 
}
void LCD_data(unsigned char data)
{
data = LCD_DATA ;  delay(50) ;  RS = 1 ; RW = 0 ; EN=1 delay(5); EN = 0 ;
}