How to Use DRV8825: Examples, Pinouts, and Specs

The DRV8825 is a high-performance stepper motor driver designed to control bipolar stepper motors with precision and efficiency. It supports microstepping, allowing for smoother and more accurate motor movements. With adjustable current control, over-temperature protection, and the ability to drive up to 2.5A per phase, the DRV8825 is a versatile component widely used in robotics, 3D printers, CNC machines, and other automation systems.

• Robotics and automation systems
• 3D printers
• CNC machines
• Camera sliders and gimbals
• Precision positioning systems

• Motor Type Supported: Bipolar stepper motors
• Operating Voltage: 8.2V to 45V
• Maximum Current per Phase: 2.5A (with sufficient cooling)
• Microstepping Modes: Full-step, 1/2, 1/4, 1/8, 1/16, 1/32
• Logic Voltage: 3.3V or 5V
• Over-Temperature Protection: Yes
• Over-Current Protection: Yes
• Adjustable Current Control: Yes (via potentiometer)
• Step Frequency: Up to 250 kHz

The DRV8825 module typically has 16 pins. Below is the pinout and description:

The microstepping mode is configured using the MS1, MS2, and MS3 pins as shown below:

1. Power Connections:

   • Connect VMOT to the motor power supply (8.2V to 45V) and GND to the power ground.
   • Add a capacitor (e.g., 100 µF) close to the VMOT and GND pins to reduce voltage spikes.
   • Connect VDD to the logic power supply (3.3V or 5V) and GND to the logic ground.

2. Motor Connections:

   • Connect the stepper motor coils to A1, A2, B1, and B2. Ensure the correct pairing of motor wires.

3. Control Signals:

   • Connect the STEP pin to a microcontroller or pulse generator to control the motor steps.
   • Use the DIR pin to set the motor's rotation direction.
   • Configure the microstepping mode using the MS1, MS2, and MS3 pins.

4. Adjusting Current Limit:

   • Use the onboard potentiometer to set the current limit. This prevents overheating and protects the motor.
   • Measure the reference voltage (VREF) on the potentiometer and calculate the current limit using the formula:

     Current Limit = VREF × 2
     

5. Enable/Disable and Sleep Mode:

   • Pull the ENABLE pin low to enable the driver or high to disable it.
   • Pull the SLEEP pin low to put the driver into low-power mode.

Below is an example of how to control a stepper motor using the DRV8825 and Arduino UNO:

• VMOT: Connect to a 12V power supply.
• GND: Connect to the power supply ground and Arduino GND.
• VDD: Connect to Arduino 5V.
• STEP: Connect to Arduino pin 3.
• DIR: Connect to Arduino pin 4.
• MS1, MS2, MS3: Set to desired microstepping mode (e.g., all LOW for full step).
• A1, A2, B1, B2: Connect to the stepper motor coils.

// Define pin connections
#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 a step pulse
  digitalWrite(STEP_PIN, HIGH); // Set STEP pin HIGH
  delayMicroseconds(500);       // Wait for 500 microseconds
  digitalWrite(STEP_PIN, LOW);  // Set STEP pin LOW
  delayMicroseconds(500);       // Wait for 500 microseconds
}

• Always set the current limit before connecting the motor to avoid damage.
• Use a heatsink or cooling fan if driving motors at high currents.
• Ensure proper decoupling capacitors are used to prevent voltage spikes.

1. Motor Not Moving:

   • Check the power supply connections and ensure VMOT and VDD are properly powered.
   • Verify the STEP signal is being sent to the driver.

2. Overheating:

   • Ensure the current limit is set correctly using the potentiometer.
   • Use a heatsink or cooling fan for high-current applications.

3. Fault Pin Active:

   • Check for over-temperature or over-current conditions.
   • Reduce the motor current or improve cooling.

4. Motor Vibrates but Does Not Rotate:

   • Verify the motor coil connections (A1, A2, B1, B2) are correct.
   • Check the microstepping configuration.

• Q: Can I use the DRV8825 with a unipolar stepper motor?
  A: No, the DRV8825 is designed for bipolar stepper motors only.

• Q: What is the maximum step frequency?
  A: The DRV8825 supports step frequencies up to 250 kHz.

• Q: How do I calculate the current limit?
  A: Measure the VREF voltage on the potentiometer and use the formula:
  Current Limit = VREF × 2.

• Q: Can I use the DRV8825 with a 24V power supply?
  A: Yes, the DRV8825 supports motor power supplies from 8.2V to 45V.