Adafruit MotorShield test dc motor

gistfile1.txt

#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include "utility/Adafruit_PWMServoDriver.h"

Adafruit_MotorShield AFMS = Adafruit_MotorShield(); 

Adafruit_DCMotor *sx = AFMS.getMotor(3), *dx =AFMS.getMotor(1);

void setup(){
 AFMS.begin();
 sx->run(FORWARD);
 dx->run(FORWARD);
 pinMode(13, OUTPUT);
}

int getmyspeed(){
  int val= millis()%9000;
  return (val<2000)? 0: (val<7000)? map(val, 2000, 6999, 0, 255) : 255;
}

int stat = HIGH;
void loop(){
  delay(100);
  stat = stat==HIGH? LOW: HIGH;
  digitalWrite(13, stat);
  dx->setSpeed(getmyspeed());
  sx->setSpeed(getmyspeed());
}