#include "MeUsb.h"
MeUsb usb(10,9); //use software serial, setting up pin for tx,rx

void setup() 
{
   Serial.begin(9600); 
   usb.init(USB1_0);
   //initialize USB Host
}
void loop()
{ 
  if(!usb.device_online)
  {
    usb.probeDevice(); 
    //poll for usb device's connection
    delay(100);
  }
  else
  {
    //received data from usb device
    int len = usb.host_recv();
    if(len>4){
      parseJoystick(usb.RECV_BUFFER);
    }
  }
}
void parseJoystick(unsigned char * buf)
{
      //parse joystick's data
      uint8_t buttonCode = buf[4]&0xff;
      uint8_t buttonCode_ext = buf[5]&0xff;
      uint8_t joystickCodeL_V = buf[3]&0xff; //top 0 bottom ff
      uint8_t joystickCodeL_H = buf[2]&0xff; //left 0 right ff
      uint8_t joystickCodeR_V = buf[1]&0xff; //top 0 bottom ff
      uint8_t joystickCodeR_H = buf[0]&0xff; //left 0 right ff
      uint8_t directionButtonCode = (buttonCode&0xf);
      uint8_t rightButtonCode = (buttonCode&0xf0)>>4;
      switch(directionButtonCode){
       ...
        case 2:{
          //motor run clockwise
          runMotor(MOTOR_1,100);
          runMotor(MOTOR_2,100);
          break;
        }
       ...
        case 6:{
          //motor run counterclockwise
          runMotor(MOTOR_1,-100);
          runMotor(MOTOR_2,-100);
          break;
        }
        ...
        default:{
          // release;
          runMotor(MOTOR_1,0);
          runMotor(MOTOR_2,0);
      }
    }
 } 
 void runMotor(int motor,int speed){
    //dc motor driver
      int _dirPin;
      int _pwmPin;
      if(motor==MOTOR_1){
        _dirPin = 7;
        _pwmPin = 6;
      }else if(motor==MOTOR_2){
        _dirPin = 4;
        _pwmPin = 5;
      }
      pinMode(_dirPin,OUTPUT);
      pinMode(_pwmPin,OUTPUT);
      digitalWrite(_dirPin,speed>0);
      analogWrite(_pwmPin,abs(speed));
}