While testing out this and the new MicroMod Teensy port, @mjs513
and myself found it desirable to have logical pin names for the
different Serial UART objects. It is a lot easier and clearer
to use and maintain to do something
like: uart4 = busio.UART(board.TX4, board.RX4)
than have to go look up the pin numbers for each board.
ecf2f1c80c