#define EN_PIN 6
#define DIR_X 4
#define STEP_X 5

int step_rev = 3200; // 360*16/1.8 = 200
int dir = 1;

void setup() {
    pinMode(EN_PIN, OUTPUT);
    pinMode(DIR_X, OUTPUT);
    pinMode(STEP_X, OUTPUT);
    Serial.begin(115200);
}

void loop() {
    digitalWrite(EN_PIN, LOW);
    if (dir > 0) {
        digitalWrite(DIR_X, LOW);
        for (int i = 0; i < step_rev; i++) {
            digitalWrite(STEP_X, HIGH);
            delay(1);
            digitalWrite(STEP_X, LOW);
            delay(1);
        }
        delay(2000);
        dir = -1;
    } else {
        digitalWrite(DIR_X, HIGH);
        for (int i = 0; i < step_rev; i++) {
            digitalWrite(STEP_X, HIGH);
            delay(1);
            digitalWrite(STEP_X, LOW);
            delay(1);
        }
        delay(2000);
        dir = 1;
    }
}