LCD --> AVR µC

// LCD 2x16 auf Port D

#define LCD_ZEILEN      2     //Anzahl der Zeilen 1,2 oder 4

#define LCD_DDR        DDRD  //Port an dem das Display angeschlossen wurde

#define LCD_OUT        PORTD

#define LCD_IN        PIND

#define LCD_RS        4     //Pin für RS

#define LCD_RW        5    //Pin für Read/Write

#define LCD_E        6     //Pin für Enable

#define LCD_DATAOUTPUT    0x0f

#define LCD_DATAINPUT    0x00

void lcd_init ()

{

  char tmp = LCD_ZEILEN;

  //Set Port Direction Register to Output for LCD Databus und LCD

Steuerbus

  LCD_DDR = LCD_DATAOUTPUT+(1<<LCD_RS | 1<<LCD_RW | 1<<LCD_E);

  //Wait a short Time afer Power on

  _delay_ms(500);

  lcd_write (0x22,0);  //Init in 4 Bit Mode

  //Wait a short Time afer Power on

  _delay_ms(50);

  lcd_write (0x22,0);  //Init in 4 Bit Mode (Zur Sicherheit nochmal)  

  if (tmp == 1)

    {

    lcd_write (0x20,0);  //1 Zeilen

    }

    else

    {

    lcd_write (0x28,0);  //mehrere Zeilen

    }

  lcd_write (0x0C,0);  //Display On

  lcd_write (0x80,0);  //Set DD-Ram Adresse = 0

  return;

}

// by Ulrich Radig

// löscht das LCD, den Text im Buffer des LCD-Structs, 

// die Cursor-Eigenschaften (nicht sichtbar, Position 0, etc.)

void lcd_clear ()

{

  lcd_write (1,0); //Clear Display

  lcd_write (0x80,0);  //Set DD-Ram Adresse = 0

  return;

}

void lcd_clear ()

{

  lcd_write (1,0); //Clear Display

  lcd_write (0x80,0);  //Set DD-Ram Adresse = 0

  return;

}

void lcd_write (char data, char type)

{

  //Set Port Direction Register to Output for LCD Databus und LCD

Steuerbus

  LCD_DDR = LCD_DATAOUTPUT+(1<<LCD_RS | 1<<LCD_RW | 1<<LCD_E);

  //Soll ins Seuer oder Datenregister geschrieben werden?

  if (type == 0)

    {

    (LCD_OUT &= ~(1<<LCD_RS));  // cbi(LCD_OUT,LCD_RS); //RS = 0

Steuerregister

    }

    else

    {

    (LCD_OUT |= (1<<LCD_RS));  // sbi(LCD_OUT,LCD_RS); //RS = 1

Dataregister

    }

  //Schreibsignal setzen

  (LCD_OUT &= ~(1<<LCD_RW));  // cbi(LCD_OUT,LCD_RW); //Zum Schreiben

RW-Pin = Low

  //Schreiben der 1. 4Bit an das LCD Display

  LCD_OUT = ((LCD_OUT & 0xF0) + ((data & 0xF0)>>4)); //Write Nibbel MSB

  (LCD_OUT |= (1<<LCD_E));  // sbi(LCD_OUT,LCD_E);

  (LCD_OUT &= ~(1<<LCD_E));  // cbi(LCD_OUT,LCD_E);

  //Schreiben der 2. 4Bit an das LCD Display  

  LCD_OUT = (LCD_OUT&0xF0) + (data&0x0F); //Write Nibbel LSB

  (LCD_OUT |= (1<<LCD_E));  // sbi(LCD_OUT,LCD_E);

  (LCD_OUT &= ~(1<<LCD_E));  // cbi(LCD_OUT,LCD_E);

  //loop_until_bit_is_clear(Read_LCD(0),BusyBit);  //Wartet bis LCD

wieder bereit

  return;

}

int main ()

{

        lcd_init();  // LCD initialiseren

  lcd_clear();

  // 2do test

  for(;;)

  lcd_write('a',1);

}