MIDI Message Information

The MIDI protocol is made up of messages. A message consists of a string (ie, series) of 8-bit bytes. These messages encode commands such;
  • Note Off
  • Note On
  • AfterTouch (ie, key pressure)
  • Control Change
  • Program (patch) change
  • Channel Pressure
  • Pitch Wheel
Text Box:  The figure on the right depicts a 3 byte MIDI NOTE ON or NOTE OFF message.

These MIDI commands encode;
  • which of 16 channels the command is to be effective for,
  • which of 128 possible notes is specified (over 10 octaves);
  • the velocity or "force" by which this command was activated (assuming a key caused the note).

    A MIDI NOTE ON message with a Velocity value of zero performs the same as a NOTE OFF command for the note value specified.  This conforms to standard MIDI "RUNNING STATUS" note assignments.   The MDD is programmed to respond to MIDI messages upon a user specified channel (Ch. 1 default).