TI TM4C123 LaunchPad USB Device problem with Energia

Dear All,

I have TI TM4C Launchpad and using Energia. 

I was trying to use Device side USB and I wrote a code to send simple 'Hello World' on device side usb.

But PC does not detect Device Side and because of that, it does not send any data via device side usb port.

Here is the code

#define LED 30

void setup()
{
  // put your setup code here, to run once:
  Serial6.begin(9600);
  pinMode(LED,OUTPUT);
}

void loop()
{
  // put your main code here, to run repeatedly:
  
  digitalWrite(LED,HIGH);
  Serial6.println("Hello World");
  delay(250);
  digitalWrite(LED,LOW);
  delay(500);
  Serial6.println("Deneme Seriport 6");
  delay(500);
}