#define m1 10
#define m2 9
#define led 13



int count=0;

int val = 0x00; //Valor entrada serie

int s0=14;
int s1=15;
int s2=16;
int flag_avan=0;
int flag_retro=0;

void setup()                    
{
  Serial.begin(9600); 
  
  pinMode(m1, OUTPUT);  
  pinMode(m2, OUTPUT); 
  pinMode(s0, OUTPUT);  
  pinMode(s1, INPUT); 
  pinMode(s2, INPUT);
  pinMode(led, OUTPUT); 
  digitalWrite(m2, LOW);
  digitalWrite(m1, LOW);
  digitalWrite(led, LOW);
  digitalWrite(s0, LOW);
  digitalWrite(s1, HIGH);
  digitalWrite(s2, HIGH);
  
}

void loop()                      //run over and over again
{
  
  if (Serial.available()) {
    val = Serial.read();
    
    if (val==0x00) 
    {
      flag_avan=1;
      avanza();
    }
    else if (val==0x01) 
    {
      flag_retro=1;
      retrocede();
    }
    else if (val==0x02) digitalWrite(led, HIGH);
    else if (val==0x03) digitalWrite(led, LOW);
  }
  
  if ((flag_retro)&&(!digitalRead(s1))) 
  {
    flag_retro=0;
    stop_motores();
  }
  else if ((flag_avan)&&(!digitalRead(s2))) 
  {
    flag_avan=0;
    stop_motores();
  }
  //if ((!digitalRead(s1))||(!digitalRead(s2))) stop_motores();
}

void stop_motores()
{
  digitalWrite(m2, LOW);
  digitalWrite(m1, LOW);
}


void avanza()
{
  digitalWrite(m2, LOW);
  digitalWrite(m1, HIGH);
}

void retrocede()
{
  digitalWrite(m2, HIGH);
  digitalWrite(m1, LOW);
}