Serial Ports for SAMD21 Xplained Pro?

Other Hardware 3rd Party Boards
10

Remember these lines I referred to back in Post #6?

I believe these lines are in error (a BUG in the core!)
B10 and B11 do not have "SERCOM" functionality, they have "SERCOM_ALT" functionality. Try changing your code to:

  Serial2.begin(115200);
  pinPeripheral(30, PIO_SERCOM_ALT);
  pinPeripheral(31, PIO_SERCOM_ALT);

(although, the code you posted seems to have the sort of mistakes common to new users of Serial interfaces, like "reading the port faster than data becomes available." See the "Serial Input Basics" tutorial