// define PINS adopted to control the motors

// PWM (velocity) control
const int VEL1 = 9;
const int VEL2 = 10;

// Polarity Control
const int M1_P1=5;
const int M1_P2=4;
const int M2_P1=3;
const int M2_P2=2;

// Initialize PINS
void setup() {
pinMode(VEL1, OUTPUT);
pinMode(VEL2, OUTPUT);
pinMode(M1_P1, OUTPUT);
pinMode(M1_P2, OUTPUT);
pinMode(M2_P1, OUTPUT);
pinMode(M2_P2, OUTPUT);

analogWrite(VEL1, 255);
analogWrite(VEL2, 255);
}

void loop() {
// both motors forward
digitalWrite(M1_P1, LOW);
digitalWrite(M1_P2, HIGH);
digitalWrite(M2_P1, LOW);
digitalWrite(M2_P2, HIGH);
delay(1000);
// both motors backward
digitalWrite(M1_P1, HIGH);
digitalWrite(M1_P2, LOW);
digitalWrite(M2_P1, HIGH);
digitalWrite(M2_P2, LOW);
delay(1000);
  
}