XIAOをMIDIインターフェースにしてみる：Seeeduino XIAO and MIDIUSB Library

#include <Arduino.h>

//#include "USB\SAMD21_USBDevice.h"

/*
 * MIDIUSB_test.ino
 *
 * Created: 4/6/2015 10:47:08 AM
 * Author: gurbrinder grewal
 * Modified by Arduino LLC (2015)
 */
#include "MIDIUSB.h"

uint8_t note_num = 0;

// First parameter is the event type (0x09 = note on, 0x08 = note off).
// Second parameter is note-on/note-off, combined with the channel.
// Channel can be anything between 0-15. Typically reported to the user as 1-16.
// Third parameter is the note number (48 = middle C).
// Fourth parameter is the velocity (64 = normal, 127 = fastest).

void noteOn(byte channel, byte pitch, byte velocity)
{
	midiEventPacket_t noteOn = {0x09, 0x90 | channel, pitch, velocity};
	MidiUSB.sendMIDI(noteOn);
}

void noteOff(byte channel, byte pitch, byte velocity)
{
	midiEventPacket_t noteOff = {0x08, 0x80 | channel, pitch, velocity};
	MidiUSB.sendMIDI(noteOff);
}

void setup()
{
	Serial.begin(115200);
	// ちょっと待つ
	delay(2000);
}

// First parameter is the event type (0x0B = control change).
// Second parameter is the event type, combined with the channel.
// Third parameter is the control number number (0-119).
// Fourth parameter is the control value (0-127).

void controlChange(byte channel, byte control, byte value)
{
	midiEventPacket_t event = {0x0B, 0xB0 | channel, control, value};
	MidiUSB.sendMIDI(event);
}

bool flag = false;

void loop()
{
	/*
  Serial.println("Sending note on");
  noteOn(0, 48, 64);   // Channel 0, middle C, normal velocity
  MidiUSB.flush();
  delay(500);
  Serial.println("Sending note off");
  noteOff(0, 48, 64);  // Channel 0, middle C, normal velocity
  MidiUSB.flush();
  delay(1500);
*/

	if (flag)
	{

		Serial.print("Sending note on at : ");
		Serial.print(note_num);
		Serial.println("");
		noteOn(0, note_num, 64); // Channel 0, middle C, normal velocity
		MidiUSB.flush();

		delay(150);

		Serial.println("Sending note off");
		noteOff(0, note_num, 64); // Channel 0, middle C, normal velocity
		MidiUSB.flush();

		delay(80);

		// 全部押し
		if (note_num > 127)
		{
			Serial.println("Sending note on at ALL");
			for (uint8_t i = 0; i < 128; i++)
			{
				noteOn(0, i, 64); // Channel 0, middle C, normal velocity
				MidiUSB.flush();
			}

			delay(800);

			Serial.println("Sending note off");
			for (uint8_t i = 0; i < 128; i++)
			{
				noteOff(0, i, 64); // Channel 0, middle C, normal velocity
				MidiUSB.flush();
			}
			delay(80);

			note_num = 0;
		}
		else
		{
			note_num++;
		}
	}
	else
	{
		// 開始ボタン
		if (Serial.available())
		{
			int inputchar = Serial.read();

			// mキー
			if (char(inputchar) == 'm')
			{
				flag = true;
			}
		}
	}

	// controlChange(0, 10, 65); // Set the value of controller 10 on channel 0 to 65
}