PWM Controller class for javelin stamp

PwmMotorController.java

import stamp.core.*;

/** PWM Controller class
  *    in main: enter to a mainloop , command from the serial
  *    is using pwm to control a dc motor
  */

class PwmMotorController {
  PWM pwm;
  char command;
  int speed;

 public static void main(){
   PwmMotorController program =
           new PwmMotorController(CPU.pin1);
   program.printMenu();
   program.mainLoop();
 }

 public PwmMotorController(int pin){
  this.speed = 255;
  this.pwm = new PWM(pin,speed,255);
  this.pwm.start();
 }

 void printMenu(){
  System.out.println("PWM Motor Controller");
  System.out.println(" type");
  System.out.println("  z : speed up");
  System.out.println("  x : speed down");
 }

 void mainLoop(){
  char command;
  while(true){
    if(Terminal.byteAvailable()){
      command = Terminal.getChar();
      if(command == 'z'){
        speedUp();
      }else if(command == 'x'){
        speedDown();
      }
      pwm.update(speed,255);
    }
  }
 }

 void speedUp(){System.out.println(" + speed: " + ++speed);}
 void speedDown(){System.out.println(" - speed: " + --speed);}
}