Documentation

// A4988 Stepper Driver - Arduino Example
// STEP = D3, DIR = D4, EN = D5
// Set VREF to your motor's rated current BEFORE first run.

#define STEP_PIN  3
#define DIR_PIN   4
#define EN_PIN    5

const int stepsPerRev = 200;       // NEMA 17 = 200 full steps/rev
const int microsteps  = 16;        // matching MS1/MS2/MS3 = HIGH/HIGH/HIGH
const int totalSteps  = stepsPerRev * microsteps;

void setup() {
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(EN_PIN, OUTPUT);
  digitalWrite(EN_PIN, LOW);   // enable driver
}

void loop() {
  digitalWrite(DIR_PIN, HIGH); // forward
  for (int i = 0; i < totalSteps; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(500);    // tune for desired RPM
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(500);
  }
  delay(500);

  digitalWrite(DIR_PIN, LOW);  // reverse
  for (int i = 0; i < totalSteps; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(500);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(500);
  }
  delay(500);
}

// A4988 - Smooth motion with AccelStepper library
// Library: AccelStepper by Mike McCauley (Library Manager)

#include <AccelStepper.h>

#define STEP_PIN 3
#define DIR_PIN  4

AccelStepper stepper(AccelStepper::DRIVER, STEP_PIN, DIR_PIN);

void setup() {
  stepper.setMaxSpeed(1000);     // steps/sec
  stepper.setAcceleration(500);  // steps/sec^2
  stepper.moveTo(3200);          // one revolution at 1/16 microstepping
}

void loop() {
  if (stepper.distanceToGo() == 0) {
    stepper.moveTo(-stepper.currentPosition());   // reverse
  }
  stepper.run();
}

# A4988 - Pico MicroPython
# STEP = GP15, DIR = GP14

from machine import Pin
import time

step = Pin(15, Pin.OUT)
direction = Pin(14, Pin.OUT)

def step_motor(steps, dir_value, delay_us=500):
    direction.value(dir_value)
    for _ in range(steps):
        step.value(1)
        time.sleep_us(delay_us)
        step.value(0)
        time.sleep_us(delay_us)

while True:
    step_motor(3200, 1)   # forward 1 rev (16x microstepping)
    time.sleep(0.5)
    step_motor(3200, 0)   # reverse
    time.sleep(0.5)