How to Use Modulo Expancion Dvr8825: Examples, Pinouts, and Specs

The DVR8825 is a high-performance stepper motor driver designed for precise control of stepper motors. It supports adjustable current control, microstepping (up to 1/32 steps), and includes built-in thermal shutdown protection. This makes it an ideal choice for applications requiring accurate motor control, such as robotics, 3D printers, CNC machines, and other automation systems.

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

The DVR8825 offers robust performance and flexibility for stepper motor control. Below are its key technical specifications:

The DVR8825 module has 16 pins. Below is the pinout and description:

The microstepping mode is configured using the MS1, MS2, and MS3 pins. The table below shows the settings:

1. Power Supply: Connect VMOT and GND to the motor power supply (8.2V to 45V). Add a capacitor (100µF or higher) across these pins to prevent voltage spikes.
2. Logic Power: Connect VDD and GND to the logic power supply (3.3V or 5V).
3. Motor Connections: Connect the stepper motor coils to A1, A2, B1, and B2. Ensure the correct pairing of motor wires.
4. Control Pins: Connect STEP, DIR, and ENABLE to your microcontroller or control circuit. Use pull-up or pull-down resistors if necessary.
5. Microstepping: Set MS1, MS2, and MS3 to configure the desired microstepping mode.
6. Optional Pins: Connect RESET and SLEEP if you need to use these features. Otherwise, tie them to VDD to keep the driver active.

Below is an example of how to control a stepper motor using the DVR8825 and an Arduino UNO:

• VMOT: Connect to a 12V power supply.
• GND (VMOT): Connect to the power supply ground.
• VDD: Connect to the Arduino 5V pin.
• GND (VDD): Connect to the Arduino GND pin.
• STEP: Connect to Arduino pin 3.
• DIR: Connect to Arduino pin 4.
• ENABLE: Connect to Arduino pin 5 (optional, can be tied to GND for always enabled).

// Define pin connections
#define STEP_PIN 3  // Pin connected to STEP
#define DIR_PIN 4   // Pin connected to DIR
#define ENABLE_PIN 5 // Pin connected to ENABLE (optional)

void setup() {
  // Set pin modes
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(ENABLE_PIN, OUTPUT);

  // Enable the driver
  digitalWrite(ENABLE_PIN, LOW); // LOW = enabled
}

void loop() {
  // Set direction
  digitalWrite(DIR_PIN, HIGH); // HIGH = one direction, LOW = opposite

  // Generate step pulses
  for (int i = 0; i < 200; i++) { // 200 steps for one revolution (1.8°/step motor)
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(500); // Adjust for speed
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(500);
  }

  delay(1000); // Wait 1 second before reversing direction

  // Reverse direction
  digitalWrite(DIR_PIN, LOW);
  for (int i = 0; i < 200; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(500);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(500);
  }

  delay(1000); // Wait 1 second before repeating
}

• Use a heatsink or active cooling if driving motors at high current.
• Always power the logic circuit (VDD) before the motor power (VMOT) to avoid damage.
• Avoid disconnecting the motor while the driver is powered to prevent damage to the driver.

1. Motor Not Moving:

   • Check the power supply connections (VMOT and VDD).
   • Verify the STEP and DIR signals from the microcontroller.
   • Ensure the motor wires are correctly paired and connected.

2. Overheating:

   • Use a heatsink or active cooling.
   • Reduce the current limit using the potentiometer.

3. Driver Not Enabling:

   • Ensure the ENABLE pin is set to LOW.
   • Check the logic power supply (VDD).

4. Erratic Motor Movement:

   • Verify the microstepping configuration (MS1, MS2, MS3).
   • Check for loose or incorrect wiring.

Q: How do I set the current limit?
A: Adjust the potentiometer on the DVR8825 while monitoring the reference voltage (VREF). Use the formula:
Current Limit = VREF × 2 (for full-step mode).

Q: Can I use the DVR8825 with a 3.3V microcontroller?
A: Yes, the DVR8825 supports logic levels of 3.3V and 5V.

Q: What happens if the driver overheats?
A: The DVR8825 has thermal shutdown protection. It will disable itself until the temperature drops to a safe level.