How to Use DRV8825: Examples, Pinouts, and Specs

The DRV8825 is a versatile microstepping driver for controlling bipolar stepper motors. With its adjustable current limiting, built-in over-current and over-temperature protection, and six microstep resolutions, it is suitable for a wide range of applications, including 3D printers, CNC machines, and robotics.

• Precision control in 3D printers
• CNC machines for milling and laser cutting
• Robotic arms and actuators
• Automated equipment and animatronics

• Motor Supply Voltage (VM): 8.2 – 45 V
• Logic Supply Voltage (VDD): 2.5 – 5.25 V
• Output Current (per channel): 1.5 A (with sufficient additional cooling up to 2.2 A)
• Microstep Resolutions: Full, 1/2, 1/4, 1/8, 1/16, 1/32
• Thermal Overload Protection: Yes
• Under-voltage Lockout: Yes
• Overcurrent Protection: Yes
• Fault Indicator: Yes

1. Power Connections: Connect the motor supply voltage (VM) to the motor power supply and the ground (GND) to the power supply ground. Connect VDD to the logic power supply (2.5 – 5.25 V).

2. Motor Connections: Connect the motor coils to the 2B, 2A, 1A, and 1B pins. Ensure the motor phases match the driver's outputs.

3. Control Inputs: Connect the STEP and DIR pins to the control signals, typically from a microcontroller like an Arduino UNO. The RESET and SLEEP pins can be connected to digital outputs or tied together if not used.

4. Microstep Selection: Set the microstep resolution by configuring the M0, M1, and M2 pins according to the truth table in the datasheet.

5. Current Limiting: Adjust the current limiting potentiometer on the DRV8825 board to match the current rating of your stepper motor.

• Always ensure the power supply voltage and current ratings are within the specifications of the DRV8825.
• Configure the current limit to prevent damage to the motor due to overcurrent.
• Use appropriate decoupling capacitors to minimize voltage spikes on the power supply lines.
• Avoid disconnecting the motor while the driver is powered to prevent damage to the DRV8825.
• Provide adequate cooling if the driver is expected to handle currents near the upper limit of its capability.

// Define the stepper motor connections and steps per revolution
#define DIR_PIN 2
#define STEP_PIN 3
#define STEPS_PER_REV 200

void setup() {
  // Set the motor control pins as outputs
  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop() {
  // Set the motor direction to clockwise
  digitalWrite(DIR_PIN, HIGH);

  // Move the motor one revolution
  for (int i = 0; i < STEPS_PER_REV; i++) {
    // Pulse the STEP pin to move the motor one step
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(1000); // Adjust the speed as necessary
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(1000);
  }

  // Pause before changing direction
  delay(1000);

  // Set the motor direction to counterclockwise
  digitalWrite(DIR_PIN, LOW);

  // Move the motor one revolution in the other direction
  for (int i = 0; i < STEPS_PER_REV; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(1000);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(1000);
  }

  // Pause before the next revolution
  delay(1000);
}

• Motor not moving: Check power supply connections, ensure the current limit is correctly set, and verify that the motor coils are properly connected.
• Overheating: Ensure adequate cooling, and check if the current limit is set too high.
• Inconsistent movement: Verify microstep resolution settings and ensure the control signals are clean and without noise.

• Motor Stalls or Misses Steps: Reduce the speed or acceleration of the motor, increase the current limit slightly, or check for mechanical obstructions.
• Driver Resets or Shuts Down: Check for overcurrent conditions or thermal overload. Add a heatsink or improve airflow around the DRV8825.
• Noise or Vibration: Experiment with different microstep resolutions or dampening materials to reduce resonance.

Q: Can I run the DRV8825 without a heatsink? A: Yes, for low to moderate current levels. However, for currents approaching the upper limit, a heatsink is recommended.

Q: What is the maximum current the DRV8825 can handle? A: The DRV8825 can handle up to 1.5 A per channel without additional cooling. With sufficient cooling, it can handle up to 2.2 A per channel.

Q: How do I adjust the current limit on the DRV8825? A: Turn the potentiometer on the DRV8825 module while measuring the voltage on the REF pin or by following the VREF formula provided in the datasheet.

Q: What should I do if the FAULT pin goes high? A: Check for overcurrent or overheating conditions. Let the driver cool down and ensure that the current limit is set correctly before resuming operation.