#define PIN_STEP 3 
#define PIN_DIR 2 

const int STEP_ROUND = 200;

const int SPEED = 10;

void setup() {
pinMode(PIN_STEP, OUTPUT);
pinMode(PIN_DIR, OUTPUT); 
}

void loop() {
digitalWrite(PIN_DIR, HIGH);
for(int j = 0; j < STEP_ROUND; j++)
 {
digitalWrite(PIN_STEP, HIGH);
delay(SPEED);
digitalWrite(PIN_STEP, LOW);
delay(SPEED);
 }

digitalWrite(PIN_DIR, LOW);

for(int j = 0; j < STEP_ROUND; j++)
  { 
digitalWrite(PIN_STEP, HIGH);
delay(SPEED);
digitalWrite(PIN_STEP, LOW);
delay(SPEED);
  }
}