How to Use the L298N Motor Driver with Arduino: Wiring and Code

The L298N motor-driver module allows Arduino to control two brushed DC motors or one bipolar stepper motor. Arduino selects direction and speed, while the module supplies the motors with current from an external power source. This separation is essential: Arduino I/O pins only provide logic signals and must not power motors directly.

What is the L298N module?

The L298N integrated circuit contains two complete H-bridges, called channel A and channel B. Each H-bridge can reverse the polarity applied to a motor, allowing the same motor to rotate in both directions. The channels are independent, so two motors can be controlled separately.

The module adds screw terminals, flyback diodes, capacitors, a heat sink and, on common boards, a 5 V regulator. It is not a stand-alone speed controller: it receives IN1-IN4 and ENA/ENB commands from Arduino.

How an H-bridge works

An H-bridge uses four electronic switches arranged around a motor. One switch pair sends current through the motor in one direction; the opposite pair reverses the current and changes motor direction.

When the two inputs of a channel are different, the motor rotates. When they are equal and the channel is enabled, the L298N performs a fast stop. When ENA or ENB is LOW, that bridge is disabled and the motor enters a freer-running stop.

L298N module pinout and components

Motor-control truth table

The same table applies to IN3 and IN4 on channel B. The words “forward” and “reverse” depend on the physical motor wiring.

How PWM controls speed

Arduino UNO does not generate a continuously variable analog voltage on normal PWM pins. Instead, analogWrite() generates a rapid pulse sequence: increasing the percentage of time spent HIGH increases the average power delivered to the motor.

The value ranges from 0 to 255: 0 disables the channel, 255 requests maximum power and intermediate values produce intermediate speeds. ENA and ENB must therefore connect to pins marked with ~, and their jumpers must be removed.

Basic Arduino UNO circuit with two motors

• ENA → Arduino PWM pin 10
• IN1 → Arduino pin 9
• IN2 → Arduino pin 8
• IN3 → Arduino pin 7
• IN4 → Arduino pin 6
• ENB → Arduino PWM pin 5
• Output A → first motor
• Output B → second motor
• motor-supply positive → module VS/12V terminal
• supply negative → module GND
• module GND → Arduino GND

A common ground is essential: Arduino and the L298N must interpret HIGH and LOW relative to the same reference. Arduino can be powered through USB or another suitable supply; never connect the motor voltage to Arduino's 5 V pin.

Choose the external supply according to the motor rated voltage and, especially, its starting and stall current. The diagram shows the module power input, but it does not mean that every motor should receive 12 V.

Fundamental code for two motors

// https://nemiatools.com

// Channel A - left motor
const byte ENA = 10; // PWM pin for speed control
const byte IN1 = 9;
const byte IN2 = 8;

// Channel B - right motor
const byte IN3 = 7;
const byte IN4 = 6;
const byte ENB = 5;  // PWM pin for speed control

void setMotorA(int speed) {
  speed = constrain(speed, -255, 255);

  if (speed > 0) {
    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    analogWrite(ENA, speed);
  }
  else if (speed < 0) {
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, HIGH);
    analogWrite(ENA, -speed);
  }
  else {
    analogWrite(ENA, 0);
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
  }
}

void setMotorB(int speed) {
  speed = constrain(speed, -255, 255);

  if (speed > 0) {
    digitalWrite(IN3, HIGH);
    digitalWrite(IN4, LOW);
    analogWrite(ENB, speed);
  }
  else if (speed < 0) {
    digitalWrite(IN3, LOW);
    digitalWrite(IN4, HIGH);
    analogWrite(ENB, -speed);
  }
  else {
    analogWrite(ENB, 0);
    digitalWrite(IN3, LOW);
    digitalWrite(IN4, LOW);
  }
}

void stopMotors() {
  setMotorA(0);
  setMotorB(0);
}

void setup() {
  pinMode(ENA, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  pinMode(ENB, OUTPUT);

  stopMotors();
}

void loop() {
  // Both motors forward at medium speed
  setMotorA(180);
  setMotorB(180);
  delay(2000);

  stopMotors();
  delay(1000);

  // Both motors in reverse
  setMotorA(-180);
  setMotorB(-180);
  delay(2000);

  stopMotors();
  delay(1000);

  // Turn in place: the motors rotate in opposite directions
  setMotorA(180);
  setMotorB(-180);
  delay(2000);

  stopMotors();
  delay(1000);
}

setMotorA() and setMotorB() accept values from -255 to 255. A positive value selects one direction, a negative value reverses the inputs and 0 disables the channel. constrain() prevents values outside the analogWrite() range.

Inside loop(), the motors run forward, stop, reverse and finally rotate in opposite directions. On a two-wheel robot, the final combination turns the robot in place.

Minimal one-motor example

// One motor on channel A
const byte ENA = 10;
const byte IN1 = 9;
const byte IN2 = 8;

void setup() {
  pinMode(ENA, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
}

void loop() {
  // Forward
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  analogWrite(ENA, 200);
  delay(2000);

  // Free-running stop: ENA set to 0
  analogWrite(ENA, 0);
  delay(1000);

  // Reverse
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  analogWrite(ENA, 200);
  delay(2000);

  analogWrite(ENA, 0);
  delay(1000);
}

Voltage drop and heating

The L298N uses bipolar transistors and introduces a significant voltage drop. The motor therefore receives less voltage than the value applied to VS, especially as current rises. This reduces efficiency and converts part of the electrical energy into heat.

The IC can reach high currents under datasheet conditions, but a small commercial module should not automatically be treated as capable of supplying 2 A continuously per channel. Usable current depends on cooling, voltage, wiring and board quality. Always check the motor stall current, not only its no-load current.

Important power rules

• do not power motors from Arduino's 5 V pin;
• always connect Arduino GND to module GND;
• use a source capable of supplying motor starting current;
• do not change wiring while power is applied;
• remove ENA/ENB jumpers when using PWM speed control;
• verify the regulator-jumper function before using the 5 V terminal;
• if the heat sink becomes very hot, stop the test and reduce the load.

L298N applications

• two-wheel Arduino robots and rovers;
• small remote-controlled vehicles;
• conveyor belts and reversible mechanisms;
• brushed-DC motor actuators;
• bipolar stepper control with the correct phase sequence.

The L298N is intended for brushed DC motors and some bipolar stepper motors. It is not the correct driver for three-phase brushless motors.

Common problems

The motors do not move

Check the external supply, common ground and ENA/ENB connections. If the enable jumpers have been removed, Arduino must output a PWM value greater than zero.

One motor turns the wrong way

Swap the two motor wires or exchange HIGH and LOW in the function for that channel.

Arduino resets when a motor starts

The source may not supply enough current, or motor noise may be reaching the logic circuit. Separate the supplies correctly, keep the common ground and use short, solid wiring.

The motor is much slower than expected

Consider the L298N voltage drop, battery charge and required motor current. Also verify that analogWrite() is not using a value that is too low.

The module becomes very hot

The motor may be drawing excessive current or may be stalled. Turn the circuit off, measure stall current and consider a more efficient driver for heavier loads.