uint8_t led = 1;   
 uint8_t knop = false;

void setup() {
 DDRB = 0b00001100;
 PORTB |= (1<<1);

 DDRD = 0b11111111;
}

void loop() {
  static uint8_t led = 1;        // lopende 1
  static uint8_t richting = 1;   // 1 = links, 0 = rechts
  static uint8_t vorig = 1;

  uint8_t huidig = PINB & (1 << PB0);

  // detecteer knopdruk (falling edge)
  if (vorig && !huidig) {
    richting = !richting;   // toggle richting
  }
  vorig = huidig;

  PORTD = led;
  delay(300);
uint8_t huidig = PINB & (1 << PB0);
  if (richting) {
    led <<= 1;
    if (led == 0) led = 1;
  } else {
    led >>= 1;
    if (led == 0) led = 0x80;
  }
}


/*

  PORTD &= ~(1 << 0);   // PC7 laag
  PORTD |=  (1 << 1);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 1);   // PC7 laag
  PORTD |=  (1 << 2);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 2);   // PC7 laag
  PORTD |=  (1 << 3);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 3);   // PC7 laag
  PORTD |=  (1 << 4);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 4);   // PC7 laag
  PORTD |=  (1 << 5);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 5);   // PC7 laag
  PORTD |=  (1 << 6);   // PC0 hoog
  delay(500);

  // toestand 2: PC7 = LOW, PC0 = HIGH
  PORTD &= ~(1 << 6);   // PC7 laag
  PORTD |=  (1 << 7);   // PC0 hoog
  delay(500);
  PORTD &= ~(1 << 7);   // PC7 laag
  PORTD |=  (1 << 0);   // PC0 hoog
  delay(500);
}
*/