sweet

void setup() {
  // put your setup code here, to run once:
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
 frente(180, 1000);
 freio(300);
 re(255, 1000);
 freio(500);
}

void frente(int pot, int temp){
  analogWrite(12, pot);
  analogWrite(13, 0);
  delay(temp);
}

void freio(int temp){
  analogWrite(12, 0);
  analogWrite(13, 0);
  delay(temp);
}

void re(int pot, int temp){
  analogWrite(12, 0);
  analogWrite(13, pot);
  delay(temp);
}