:mod:`usb_midi`
===============

.. py:module:: usb_midi

.. autoapi-nested-parse::

   MIDI over USB

   The `usb_midi` module contains classes to transmit and receive MIDI messages over USB.





.. data:: ports
   :annotation: :Tuple[Union[PortIn, PortOut], ...]

   Tuple of all MIDI ports. Each item is ether `PortIn` or `PortOut`.


.. py:class:: PortIn

   Receives midi commands over USB

   You cannot create an instance of `usb_midi.PortIn`.

   PortIn objects are constructed for every corresponding entry in the USB
   descriptor and added to the ``usb_midi.ports`` tuple.

   .. method:: read(self, nbytes: Optional[int] = None) -> Optional[bytes]

      Read characters.  If ``nbytes`` is specified then read at most that many
      bytes. Otherwise, read everything that arrives until the connection
      times out. Providing the number of bytes expected is highly recommended
      because it will be faster.

      :return: Data read
      :rtype: bytes or None


   .. method:: readinto(self, buf: WriteableBuffer, nbytes: Optional[int] = None) -> Optional[bytes]

      Read bytes into the ``buf``.  If ``nbytes`` is specified then read at most
      that many bytes.  Otherwise, read at most ``len(buf)`` bytes.

      :return: number of bytes read and stored into ``buf``
      :rtype: bytes or None



.. py:class:: PortOut

   Sends midi messages to a computer over USB

   You cannot create an instance of `usb_midi.PortOut`.

   PortOut objects are constructed for every corresponding entry in the USB
   descriptor and added to the ``usb_midi.ports`` tuple.

   .. method:: write(self, buf: ReadableBuffer) -> Optional[int]

      Write the buffer of bytes to the bus.

      :return: the number of bytes written
      :rtype: int or None