// Motor A connections
int enA = 2;
int in1 = 48;
int in2 = 47;
// Motor B connections
int enB = 42;
int in3 = 21;
int in4 = 20;

void setup() {
  Serial.begin(115200);
  // Set all the motor control pins to outputs
  pinMode(enA, OUTPUT);
  pinMode(enB, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);

  // Turn off motors - Initial state
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, LOW);

  digitalWrite(enA, LOW);
  digitalWrite(enB, LOW);
}

void loop() {
  //accelerate motor
  int speed2 = 255;
  for (int speed = 0; speed < 255; ++speed) {
    digitalWrite(in1, 1);
    digitalWrite(in2, 0);
    analogWrite(enA, speed);
    digitalWrite(in3, 0);
    digitalWrite(in4, 1);
    analogWrite(enB, speed);
    delay(25);
    Serial.print("Speed: ");
    Serial.println(speed);
  }
  for (int speed = 255; speed > 0; --speed) {
    digitalWrite(in1, 1);
    digitalWrite(in2, 0);
    analogWrite(enA, speed);
    digitalWrite(in3, 0);
    digitalWrite(in4, 1);
    analogWrite(enB, speed);
    delay(25);
    Serial.print("Speed: ");
    Serial.println(speed);
  }
  //delay(1000);
  for (int speed = 0; speed < 255; ++speed) {
    digitalWrite(in1, 0);
    digitalWrite(in2, 1);
    analogWrite(enA, speed);
    digitalWrite(in3, 1);
    digitalWrite(in4, 0);
    analogWrite(enB, speed);
    delay(25);
    Serial.print("Speed: ");
    Serial.println(speed);
  }
  for (int speed = 255; speed > 0; --speed) {
    digitalWrite(in1, 0);
    digitalWrite(in2, 1);
    analogWrite(enA, speed);
    digitalWrite(in3, 1);
    digitalWrite(in4, 0);
    analogWrite(enB, speed);
    delay(25);
    Serial.print("Speed: ");
    Serial.println(speed);
  }
  //delay(1000);
}