MIDIUSB

This library allows any microcontroller with native USB capabilities (atmega32u4 based boards or ARM boards) to appear as a MIDI peripheral over USB to a connected computer.

The library is compatible with PluggableUSB-ready cores (AVR core > 1.6.8, SAM core > 1.6.4, SAMD core > 1.6.1)

The library creates the following data type

1typedef struct {
2    uint8_t header;   // cable + command
3    uint8_t byte1;    // command + channel
4    uint8_t byte2;    // note number or other data
5    uint8_t byte3;    // velocity or other data or zero.
6} midiEventPacket_t;

Note that a USB MIDI message contains an extra byte, compared to a UART MIDI message. The

header

The library exposes the following functions

1midiEventPacket_t read(void);

Read a USB message from USB. If no message is available, the result "header" will be zero.

1void sendMIDI(midiEventPacket_t event);

Send a single USB message.

1void flush(void);

Wait for all messages to actually be sent.

1uint32_t available(void);

Return the number of USB messages that are available and unread.

1size_t write(const uint8_t *buffer, size_t size);

Write possubly multiple messages to USB. size_t should be a multiple of four.

Examples

• MIDIUSB_read Trivial example that dumps received messages to Serial debug statements.

• MIDIUSB_write Trivial example that sends a middle C note lasting 500ms every two second.

• MIDIUSB_loop Trivial MIDI loopback. Resends each MIDI message that is received.

• MIDI Device More complex example: implements a MIDI keyboard that scans 7 buttons and sends MIDI NoteOn/NoteOff messages.

• MIDIUSB_buzzer More complex example: implements a MIDI sound device Uses MidiUSB.read() to read MIDI messages; converts noteOn and noteOff messages to actual tones using the TONE library. Also interprets controlChange to text on Serial, and dumps any other messages in debug format.

• MIDIUSB_clock Simple example of beat clock based on MIDI pulse messages received from software. Interprets message types 0xF8, 0xFA, and 0xFC

• MIDI Library MIDIUSB can be used as the "transport layer" for the more advanced Arduino MIDI library.