#include <AccelStepper.h>

const uint8_t PIN_STEP = D0;
const uint8_t PIN_DIR  = D1;
const uint8_t PIN_EN   = D2;

AccelStepper stepper(AccelStepper::DRIVER, PIN_STEP, PIN_DIR);

void setup() {
  pinMode(PIN_EN, OUTPUT);
  digitalWrite(PIN_EN, LOW);

  stepper.setMaxSpeed(6400);
  stepper.setAcceleration(3200);
  stepper.setCurrentPosition(0);
}

void loop() {
  stepper.runToNewPosition(16000);
  delay(500);
  stepper.runToNewPosition(0);
  delay(500);
}