Which one are you using?
The one closest to the reset button, I believe its the native...
This is more confusing than I realized. The Due has two ports:
Programming port
For programming, the programming port is easiest to use. And you can "talk" to the serial port using Serial, like this:
void setup ()
{
Serial.begin (115200);
Serial.println ("Hello, world!");
} // end of setup
void loop ()
{
} // end of loop
Native USB port
This lets you emulate USB devices (eg. keyboard, mice). However if you want to use it for Serial communications you need to use a different class SerialUSB like this:
void setup ()
{
SerialUSB.begin(115200);
while (!SerialUSB) ; // wait for it to become ready
SerialUSB.println ("Starting ...");
} // end of setup
unsigned long i;
void loop ()
{
SerialUSB.print ("Hello, world! Count = ");
SerialUSB.println (++i);
delay (1000);
} // end of loop
It also helps to wait for the serial port to become ready, as I did in setup. Otherwise you may miss the first 10 lines or so of serial output.
