#define STEP 2
#define DIR 5
int TIMESTEP = 5;
int pasos = 50;

void setup()
{
  pinMode(STEP, OUTPUT);
  pinMode(DIR, OUTPUT);
}

void loop()
{
  digitalWrite(DIR, HIGH);
  for(int i = 0; i<pasos; i++)
  {
    digitalWrite(STEP, HIGH);
    delay(TIMESTEP);
    digitalWrite(STEP, LOW);
    delay(TIMESTEP);
  }
   digitalWrite(DIR, LOW);
  for(int i = 0; i<pasos; i++)
  {
    digitalWrite(STEP, HIGH);
    delay(TIMESTEP);
    digitalWrite(STEP, LOW);
    delay(TIMESTEP);
  } 
}