Fehlersuche 2 Tasten - 2 LED / Anfängerfrage

#include <avr/io.h>

#include <util/delay.h>

#include <inttypes.h>

#define LED_AN(LED)  (PORTD |=  (1<<(LED)))

#define LED_AUS(LED)  (PORTD &= ~(1<<(LED)))

#define LED_TOGGLE(LED)  (PORTD ^=  (1<<(LED)))

#define LED1  PD0

#define LED2  PD1

// tester 1 

#define TASTER1  PD2

#define TASTER1_GEDRUECKT()  (PIND & (1<<TASTER1))

#define TASTE1_AUF 0

#define TASTE1_ZU  1

// taster 2

#define TASTER2  PD3

#define TASTER2_GEDRUECKT()  (PIND & (1<<TASTER2))

#define TASTE2_AUF 0

#define TASTE2_ZU  1

int main(void)

{

  uint8_t alter_tastenzustand1 = TASTE1_AUF;

  uint8_t alter_tastenzustand2 = TASTE2_AUF;

  DDRD &= ~(1<<TASTER1) | (1<<TASTER2);

  DDRD |= (1<<LED1) | (1<<LED2);

  while(1)

  {

  if (TASTER1_GEDRUECKT() && (alter_tastenzustand1 == TASTE1_AUF))

      {

       LED_TOGGLE(LED1);

    alter_tastenzustand1 = TASTE1_ZU;

      }

  if (!TASTER1_GEDRUECKT())

      alter_tastenzustand1 = TASTE1_AUF;

  }

// led 2

  if (TASTER2_GEDRUECKT() && (alter_tastenzustand2 == TASTE2_AUF))

      {

    LED_TOGGLE(LED2);

    alter_tastenzustand2 = TASTE2_ZU;

      }

  if (!TASTER2_GEDRUECKT())

      alter_tastenzustand2 = TASTE2_AUF;

}