//This motor shield use Pin 6,5,7,4 to control the motor
// Simply connect your motors to M1+,M1-,M2+,M2-
// Upload the code to Arduino/Roboduino
// Through serial monitor, type 'a','s', 'w','d','x' to control the motor
// www.dfrobot.com
// Last modified on 24/12/2009
int  EN1 =   6;
int  EN2 =   5; //Roboduino Motor shield uses Pin 9
int  IN1 =   7;
int  IN2 =   4; //Latest version use pin 4 instead of pin 8
void Motor1(int pwm, boolean reverse)
         {
             analogWrite(EN1,pwm); //set pwm control, 0 for stop, and 255 for
maximum speed
           if(reverse)
           {
             digitalWrite(IN1,HIGH);
           }
         else
         {
             digitalWrite(IN1,LOW);
           }
         }
void Motor2(int pwm, boolean reverse)
         {
             analogWrite(EN2,pwm);
           if(reverse)
           {
             digitalWrite(IN2,HIGH);
           }
         else
         {
             digitalWrite(IN2,LOW);
           }
         }
void setup()
{
     int i;
    // for(i=6;i<=9;i++) //For Roboduino Motor Shield
    // pinMode(i, OUTPUT); //set pin 6,7,8,9 to output mode

    for(i=5;i<=8;i++) //For Arduino Motor Shield
    pinMode(i, OUTPUT); //set pin 4,5,6,7 to output mode

    Serial.begin(9600);
}
void loop()
{
  int x,delay_en;
  char val;
  while(1)
  {
    val = Serial.read();
    if(val!=-1)
       {
           switch(val)
            {
              case 'w'://Move ahead
                         Motor1(100,true);  //You can change the speed, such
as Motor(50,true)
                         Motor2(100,true);
                          break;
              case 'x'://move back
                         Motor1(100,false);
                         Motor2(100,false);
                          break;
              case 'a'://turn left
                         Motor1(100,false);
                         Motor2(100,true);
                          break;
              case 'd'://turn right
                         Motor1(100,true);
                         Motor2(100,false);
                         break;
                case 's'://stop
                         Motor1(0,false);
                         Motor2(0,false);
                          break;
            }
       }
  }
}