How to Use A4988 Stepper Motor Driver (Red): Examples, Pinouts, and Specs

The A4988 Stepper Motor Driver (Red) is a compact and versatile driver module designed for controlling bipolar stepper motors. It features adjustable current control, microstepping capabilities (up to 1/16 steps), and built-in thermal shutdown protection, making it ideal for applications requiring precise motor control. This driver is widely used in 3D printers, CNC machines, robotics, and other motion control systems.

• 3D printers for precise movement of axes
• CNC machines for accurate tool positioning
• Robotics for controlling stepper motors in robotic arms or wheels
• Automated systems requiring stepper motor control

• Operating Voltage (VMOT): 8V to 35V
• Logic Voltage (VDD): 3.3V or 5V
• Maximum Output Current: 2A per coil (with sufficient cooling)
• Microstepping Modes: Full, 1/2, 1/4, 1/8, and 1/16 steps
• Current Control: Adjustable via onboard potentiometer
• Thermal Protection: Over-temperature shutdown
• Overcurrent Protection: Yes
• Dimensions: 20mm x 15mm x 11mm (approx.)

The A4988 module has 16 pins, divided into two sides. Below is the pin configuration:

1. Power Connections:

   • Connect VMOT and GND to the stepper motor's power supply (8V to 35V).
   • Connect VDD and GND to the logic power supply (3.3V or 5V).

2. Motor Connections:

   • Connect the stepper motor's two coils to the 1A, 1B, 2A, and 2B pins. Ensure the correct pairing of the motor wires.

3. Control Signals:

   • Connect the STEP pin to a microcontroller's digital output pin for step control.
   • Connect the DIR pin to another digital output pin for direction control.
   • Optionally, connect ENABLE, RESET, and SLEEP pins to control the driver's state.

4. Microstepping Configuration:

   • Use MS1, MS2, and MS3 pins to set the desired microstepping mode. Refer to the table below:

5. Adjusting Current Limit:
   • Use the onboard potentiometer to set the current limit. This prevents overheating and ensures safe operation. Turn clockwise to increase the limit and counterclockwise to decrease it.

Below is an example of how to control a stepper motor using the A4988 and an Arduino UNO:

// Define control pins
#define STEP_PIN 3  // Pin connected to STEP
#define DIR_PIN 4   // Pin connected to DIR

void setup() {
  pinMode(STEP_PIN, OUTPUT); // Set STEP pin as output
  pinMode(DIR_PIN, OUTPUT);  // Set DIR pin as output

  digitalWrite(DIR_PIN, HIGH); // Set initial direction (HIGH = clockwise)
}

void loop() {
  // Generate step pulses
  digitalWrite(STEP_PIN, HIGH); // Set STEP pin HIGH
  delayMicroseconds(1000);      // Wait 1ms (adjust for speed)
  digitalWrite(STEP_PIN, LOW);  // Set STEP pin LOW
  delayMicroseconds(1000);      // Wait 1ms (adjust for speed)
}

• Always set the current limit before connecting the motor to avoid damage.
• Use a heatsink or active cooling if operating near the maximum current rating.
• Ensure proper decoupling capacitors are installed between VMOT and GND to prevent voltage spikes.

1. Motor Not Moving:

   • Check all power and motor connections.
   • Verify that the STEP and DIR signals are being sent correctly.
   • Ensure the current limit is set appropriately for the motor.

2. Driver Overheating:

   • Reduce the current limit using the potentiometer.
   • Add a heatsink or active cooling to the driver.

3. Motor Vibrating but Not Rotating:

   • Verify the correct pairing of motor wires to the 1A, 1B, 2A, and 2B pins.
   • Check the microstepping configuration.

4. Erratic Motor Movement:

   • Ensure a stable power supply for both VMOT and VDD.
   • Add decoupling capacitors to reduce noise.

• Can I use the A4988 with a unipolar stepper motor? No, the A4988 is designed for bipolar stepper motors only.

• What happens if I exceed the current limit? The driver will enter thermal shutdown to protect itself, but this may cause erratic motor behavior. Always set the current limit properly.

• Can I control multiple stepper motors with one A4988? No, each A4988 driver can control only one bipolar stepper motor.

By following this documentation, you can effectively use the A4988 Stepper Motor Driver (Red) in your projects for precise and reliable stepper motor control.