const int DIR = 14;
const int STEP = 12;
const int steps_per_rev = 200;

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

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(DIR, HIGH);

  for (int i =0; i <= steps_per_rev; i++){
    digitalWrite(STEP, HIGH);
    delay(100);
    digitalWrite(STEP, LOW);
    delay(100);
  }

  digitalWrite(DIR, LOW);
  for (int i =0; i <= steps_per_rev; i++){
    digitalWrite(STEP, HIGH);
    delay(100);
    digitalWrite(STEP, LOW);
    delay(100);
  }
}