Garbage using serial functions in Arduino Due

Hardware Arduino Due
5

Edit: after I posted the stuff below, I changed the baud rate on your sketch to 115200 in Serial.begin. Now the garbage looks like this:

DDÄI recei?é 0
I received: 0

I have the same problem with many sketches. The problem also involves Serial.read(), there is garbage when you use Serial.available().

In your sketch, it appears to execute the code after this if statement:

if (Serial.available() > 0) {

Your output is garbled stuff from these print calls:

  Serial.print("I received: ");
  Serial.println(incomingByte, DEC);

Note how often you get "I re" as part of the garbage. The 255 suggests you read 0XFF.