A4988 Stepper Motor Driver Module

The A4988 Stepper Motor Driver is a popular and compact module used to control bipolar stepper motors, such as the NEMA 17, with high precision and variable microstepping. It is commonly used in 3D printers, CNC machines, and robotics.

Technical Specifications:

• Input Voltage (VMOT): 8V to 35V DC
  
• Logic Voltage (VDD): 3V–5.5V (usually powered from Arduino 5V)
  
• Motor Type: Bipolar Stepper Motors
  
• Current per Phase: Up to 2A (with sufficient cooling)
  
• Microstepping: Full, 1/2, 1/4, 1/8, 1/16 (selectable via MS1–MS3)
  
• Step Interface: STEP and DIR pins
  
• Protections: Over-temperature, under-voltage, and short-to-ground
  
• Step Frequency: Up to 500 kHz
  
• Sleep Mode: Available (via SLEEP pin – LOW to enter sleep mode)

Pinouts:

Front View

Back View

Connection with Arduino:

A4988 Pins	Arduino Pins	Description
VDD	5V	Logic power input
GND	GND	Logic ground
VMOT	External 12V–24V +	Motor power supply
GND	External Power Supply -	Motor power ground
STEP	Pin 3	Step signal
DIR	Pin 4	Direction control
ENABLE	Pin 5 (Optional)	Enable (active LOW) or tie to GND
MS1, MS2, MS3	VCC or GND	Select microstepping mode
RESET	Tie to SLEEP	Keeps the driver active
SLEEP	Tie to RESET	Keeps the driver awake
OUT1A/1B, OUT2A/2B	Stepper Motor	Stepper Motor Connect the stepper motor coils

Microstepping Setup

MS1	MS2	MS3	Microstepping
LOW	LOW	LOW	Full step
HIGH	LOW	LOW	Half step
LOW	HIGH	LOW	1/4 step
HIGH	HIGH	LOW	1/8 step
HIGH	HIGH	HIGH	1/16 step

 

Sample code:

// A4988 connection pins
#define STEP_PIN 3
#define DIR_PIN 4

// Number of steps per revolution (change as needed)
#define STEPS_PER_REV 200  // Typical for NEMA 17 with full steps

void setup() {
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
}

void loop() {
  // Rotate one revolution clockwise
  digitalWrite(DIR_PIN, HIGH);
  for (int i = 0; i < STEPS_PER_REV; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(1000);  // Speed control
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(1000);
  }
  delay(1000);  // Pause between rotations

  // Rotate one revolution counter-clockwise
  digitalWrite(DIR_PIN, LOW);
  for (int i = 0; i < STEPS_PER_REV; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(1000);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(1000);
  }
  delay(1000);
}