Introduction

The L298N is a high-voltage, high-current dual full-bridge driver designed to control inductive loads like DC motors and stepper motors. This module can drive two DC motors bidirectionally or one stepper motor with up to 2A per channel.

Key Features

Technical Specifications

Pin Configuration

Terminal	Function	Connection
+12V	Motor Power (5-35V)	Battery positive
GND	Ground	Battery negative
+5V	Logic Power (optional)	5V (if jumper removed)
ENA	Channel A Enable	PWM capable pin
IN1/IN2	Channel A Control	Digital pins
IN3/IN4	Channel B Control	Digital pins
ENB	Channel B Enable	PWM capable pin
OUT1/OUT2	Channel A Motor	Motor A terminals
OUT3/OUT4	Channel B Motor	Motor B terminals

Wiring Diagrams

Dual DC Motor Control

// Connections:
// +12V → Battery positive (7V-35V)
// GND → Battery negative
// ENA → D9 (PWM)
// IN1 → D8
// IN2 → D7
// ENB → D10 (PWM)
// IN3 → D6
// IN4 → D5
// OUT1/OUT2 → Motor A
// OUT3/OUT4 → Motor B

Stepper Motor Control

// Connections for 4-wire bipolar stepper:
// +12V → Appropriate voltage for stepper
// OUT1 → Coil 1+
// OUT2 → Coil 1-
// OUT3 → Coil 2+
// OUT4 → Coil 2-
// ENA & ENB → Always HIGH (jumper in place)

Basic DC Motor Control

// Motor A connections
const int enA = 9;
const int in1 = 8;
const int in2 = 7;

void setup() {
  pinMode(enA, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  
  // Initial state - motor off
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
}

void loop() {
  // Rotate clockwise at full speed
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  analogWrite(enA, 255); // Full speed
  delay(2000);
  
  // Rotate counter-clockwise at half speed
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
  analogWrite(enA, 128); // Half speed
  delay(2000);
  
  // Motor brake
  digitalWrite(in1, HIGH);
  digitalWrite(in2, HIGH);
  delay(1000);
  
  // Motor stop
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  delay(1000);
}

Stepper Motor Control

const int stepsPerRevolution = 200; // Change for your stepper
const int in1 = 8, in2 = 7, in3 = 6, in4 = 5;
int stepDelay = 5; // ms between steps

void stepMotor(int step) {
  switch(step) {
    case 0:  // 1000
      digitalWrite(in1, HIGH);
      digitalWrite(in2, LOW);
      digitalWrite(in3, LOW);
      digitalWrite(in4, LOW);
      break;
    case 1:  // 1100
      digitalWrite(in1, HIGH);
      digitalWrite(in2, HIGH);
      digitalWrite(in3, LOW);
      digitalWrite(in4, LOW);
      break;
    case 2:  // 0100
      digitalWrite(in1, LOW);
      digitalWrite(in2, HIGH);
      digitalWrite(in3, LOW);
      digitalWrite(in4, LOW);
      break;
    case 3:  // 0110
      digitalWrite(in1, LOW);
      digitalWrite(in2, HIGH);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, LOW);
      break;
    case 4:  // 0010
      digitalWrite(in1, LOW);
      digitalWrite(in2, LOW);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, LOW);
      break;
    case 5:  // 0011
      digitalWrite(in1, LOW);
      digitalWrite(in2, LOW);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, HIGH);
      break;
    case 6:  // 0001
      digitalWrite(in1, LOW);
      digitalWrite(in2, LOW);
      digitalWrite(in3, LOW);
      digitalWrite(in4, HIGH);
      break;
    case 7:  // 1001
      digitalWrite(in1, HIGH);
      digitalWrite(in2, LOW);
      digitalWrite(in3, LOW);
      digitalWrite(in4, HIGH);
      break;
  }
}

void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
}

void loop() {
  // Rotate CW
  for(int i=0; i<stepsPerRevolution; i++) { stepMotor(i % 8); delay(stepDelay); } delay(1000); // Rotate CCW for(int i=stepsPerRevolution; i>0; i--) {
    stepMotor(i % 8);
    delay(stepDelay);
  }
  
  delay(1000);
}

Advanced Features

float readCurrent(int sensorPin) {
  int rawValue = analogRead(sensorPin);
  float voltage = rawValue * (5.0 / 1023.0);
  float current = voltage / 0.1; // 0.1Ω sense resistor
  return current;
}

void checkOverCurrent() {
  if(readCurrent(A0) > 2.0) { // 2A threshold
    digitalWrite(enA, LOW); // Emergency stop
    Serial.println("OVER CURRENT!");
  }
}

void smoothStart(int motorPin) {
  for(int i=0; i<=255; i+=5) { analogWrite(motorPin, i); delay(50); } } void smoothStop(int motorPin) { for(int i=255; i>=0; i-=5) {
    analogWrite(motorPin, i);
    delay(50);
  }
}

void processSerialCommands() {
  if(Serial.available()) {
    char cmd = Serial.read();
    switch(cmd) {
      case 'F': // Forward
        digitalWrite(in1, HIGH);
        digitalWrite(in2, LOW);
        break;
      case 'B': // Backward
        digitalWrite(in1, LOW);
        digitalWrite(in2, HIGH);
        break;
      case 'S': // Stop
        digitalWrite(in1, LOW);
        digitalWrite(in2, LOW);
        break;
      case '0'...'9': // Speed 0-9
        int speed = map(cmd-'0', 0, 9, 0, 255);
        analogWrite(enA, speed);
        break;
    }
  }
}

Troubleshooting