const uint8_t leds[8] = {0,1,2,3,4,5,6,7};
char valores[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,
                0x40,0x20,0x10,0x08,0x04,0x02};

void setup() {
  // put your setup code here, to run once:
  pinMode(12, INPUT_PULLUP);
      for(int i=0;i<8;i++)
        pinMode(leds[i], OUTPUT);
}

void mostrarByte(uint8_t valor)
{
    for(int i=0;i<8;i++)
    {
        digitalWrite(leds[i], (valor >> i) & 1);
    }
}

void loop() {
  // put your main code here, to run repeatedly:
  for(unsigned char xvar=0;xvar<14;xvar++){
    mostrarByte(valores[xvar]);
    if(digitalRead(12) == LOW){
      delay(100);
    }
    else{
      delay(300);
    }
  }
}