Arduino L298 H bridge example

motor.ino

#define MOTOR_A_PIN_9 9
#define MOTOR_A_PIN_10 10

#define MOTOR_B_PIN_11 11
#define MOTOR_B_PIN_12 12


void setup() {
  Serial.begin(115200);
  delay(300);

  pinMode(LED_BUILTIN, OUTPUT);

  pinMode(MOTOR_A_PIN_9, OUTPUT);
  pinMode(MOTOR_A_PIN_10, OUTPUT);
  pinMode(MOTOR_B_PIN_11, OUTPUT);
  pinMode(MOTOR_B_PIN_12, OUTPUT);

  digitalWrite(9, LOW);
  digitalWrite(MOTOR_A_PIN_10, LOW);

  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(300);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(300);                       // wait for a second
}

int i = 0;

void off(int motor) {
    Serial.print(motor == 0 ? "A" : "B"); Serial.println(" off");
    if (motor == 0) {
      digitalWrite(MOTOR_A_PIN_9, LOW);
      digitalWrite(MOTOR_A_PIN_10, LOW);
    } else {
      digitalWrite(MOTOR_B_PIN_11, LOW);
      digitalWrite(MOTOR_B_PIN_12, LOW);      
    }
}

void forward(int motor) {
    Serial.print(motor == 0 ? "A" : "B"); Serial.println(" fwd");
    if (motor == 0) {
      digitalWrite(MOTOR_A_PIN_9, LOW);
      digitalWrite(MOTOR_A_PIN_10, HIGH);
    } else {
      digitalWrite(MOTOR_B_PIN_11, LOW);
      digitalWrite(MOTOR_B_PIN_12, HIGH);      
    }
}

void backward(int motor) {
    Serial.print(motor == 0 ? "A" : "B"); Serial.println(" bwd");
    if (motor == 0) {
      digitalWrite(MOTOR_A_PIN_9, HIGH);
      digitalWrite(MOTOR_A_PIN_10, LOW);
    } else {
      digitalWrite(MOTOR_B_PIN_11, HIGH);
      digitalWrite(MOTOR_B_PIN_12, LOW);      
    }
}

void loop() {
  i++;

  int pattern = i % 6;

  Serial.print("pattern"); Serial.println(pattern);

  if (pattern == 1) {
    forward(0);  
  } else if (pattern == 2) {
    backward(0);  
  } else if (pattern == 3) {
    off(0);
  } else if (pattern == 4) {
    forward(1);  
  } else if (pattern == 5) {
    backward(1);    
  } else {
    off(1);
  }
  delay(1000);
}