const char USB_DEVICE_DESC[USB_DESC_DEVICE_LEN] ={
      //starts of with device configuration. only one possible
        USB_DESC_DEVICE_LEN, //the length of this report  ==0
        0x01, //the constant DEVICE (DEVICE 0x01)  ==1
        0x10,0x01, //usb version in bcd  ==2,3
        0x02, //class code. 0x02=Communication Device Class ==4
        0x00, //subclass code ==5
        0x00, //protocol code ==6
        USB_MAX_EP0_PACKET_LENGTH, //max packet size for endpoint 0. (SLOW SPEED SPECIFIES 8) ==7
        0xD8,0x04, //vendor id ==8,9 ESTE ES EL PID Y EL VID DEL DISPOSITIVO
        0x0a,0x00, //product id  ==10,11
        0x00,0x01, //device release number  ==12,13
        0x01, //index of string description of manufacturer. therefore we point to string_1 array (see below)  ==14
        0x02, //index of string descriptor of the product  ==15
        0x00, //index of string descriptor of serial number  ==16
        USB_NUM_CONFIGURATIONS  //number of possible configurations  ==17
  };