// STEP -> pin 3, DIR -> pin 4, ENABLE -> pin 5
// Assumes a 200-step-per-rev motor (1.8° full step) and A4988 in full-step mode.
// If you change microstepping, set STEPS_PER_REV accordingly.

const uint8_t STEP_PIN   = 3;
const uint8_t DIR_PIN    = 4;
const uint8_t ENABLE_PIN = 5;

const unsigned int STEPS_PER_REV = 1000;   // change to 1600 for 1/16 microstep, etc.
const unsigned long STEP_DELAY_US = 1000; // pulse spacing in microseconds (controls speed)

void stepOne(bool dir) {
  digitalWrite(DIR_PIN, dir ? HIGH : LOW);
  digitalWrite(STEP_PIN, HIGH);
  delayMicroseconds(2);               // STEP pulse width (min 1-2 µs)
  digitalWrite(STEP_PIN, LOW);
  delayMicroseconds(STEP_DELAY_US);   // time between steps
}

void stepRevolution(bool dir) {
  for (unsigned int i = 0; i < STEPS_PER_REV; ++i) {
    stepOne(dir);
  }
}

void setup() {
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(ENABLE_PIN, OUTPUT);
  digitalWrite(ENABLE_PIN, LOW); // ENABLE is active LOW on many A4988 modules (LOW = enabled)
}

void loop() {
  stepRevolution(true);    // one full revolution clockwise
  delay(2000);             // pause 2 seconds
  stepRevolution(false);   // one full revolution counterclockwise
  delay(2000);             // pause 2 seconds before repeating
}