Merge pull request #65 from DhrBaksteen/OPL2_MIDI_Example

OPL2 MIDI Synth example

Author: DhrBaksteen

build

@@ -20,7 +20,7 @@ echo "\033[1;34m        \\/       \\/           \\/       \\/     \033[0m"
 echo "For the \033[1;36mOPL2 Audio Board\033[0m and \033[1;36mOPL3 Duo!\033[0m synthesizers"
 echo ""
 echo "Installation script for Raspberry Pi and compatibles"
-echo "Library version 2.0.2, 14th of November 2020"
+echo "Library version 2.0.3, 23rd of November 2020"
 echo "Copyright (c) 2016-2020 Maarten Janssen, Cheerful"
 echo ""
 

examples/OPL2AudioBoard/MidiSynth/MidiSynth.ino

@@ -0,0 +1,232 @@
+/**
+ * This is an example sketch for the OPL2 Audio Board that shows how MIDI controls can be used to change the properties
+ * of an operator. In this example we assume that serial MIDI data is received from a MIDI shield connected to the Rx(1)
+ * pin of the Arduino.
+ *
+ * The carriers of all OPL2 channels will be set to some preset values and with you MIDI controller or keyboard you can
+ * play notes. The controls of the MIDI controller can be used to change ADRS, waveform and multiplier ot the carriers.
+ *
+ * In this example we assume that a MIDI controller is used that has at least 6 rotary encoders and that each rotary
+ * encoder controls a different channel. The channel of the control determines what property of the carrier is changed.
+ * If your MIDI controller is layed out differently you can adjust the changeControl function according to your setup.
+ *
+ * Code by Maarten Janssen (maarten@cheerful.nl) 2020-11-23
+ * Most recent version of the library can be found at my GitHub: https://github.com/DhrBaksteen/ArduinoOPL2
+ * WWW.CHEERFUL.NL
+ */
+
+#include <OPL2.h>
+#include <midi_instruments.h>
+
+// MIDI statuses
+#define MIDI_NOTE_OFF           0x80
+#define MIDI_NOTE_ON            0x90
+#define MIDI_POLY_AFTERTOUCH    0xA0
+#define MIDI_CONTROL_CHANGE     0xB0
+#define MIDI_PROGRAM_CHANGE     0xC0
+#define MIDI_CHANNEL_AFTERTOUCH 0xD0
+#define MIDI_SYSEX_START        0xF0
+#define MIDI_SYSEX_END          0xF7
+
+#define NUM_OPL2_CHANNELS 9
+#define NO_NOTE 255
+
+byte midiCommand = 0x00;
+byte midiChannel = 0;
+byte midiData[2] = { 0x00, 0x00 };
+byte midiDataBytes = 0;
+byte midiDataIndex = 0;
+
+byte oplChannel = 0;
+byte oplNotes[NUM_OPL2_CHANNELS] = {
+	NO_NOTE, NO_NOTE, NO_NOTE,
+	NO_NOTE, NO_NOTE, NO_NOTE,
+	NO_NOTE, NO_NOTE, NO_NOTE
+};
+
+OPL2 opl2;
+Instrument instrument;
+
+
+void setup() {
+	Serial.begin(31250);
+	opl2.begin();
+
+	// Set properties for all channels.
+	opl2.setWaveFormSelect(true);
+	for (byte i = 0; i < opl2.getNumChannels(); i ++) {
+		opl2.setTremolo   (i, CARRIER, true);
+		opl2.setVibrato   (i, CARRIER, true);
+		opl2.setMultiplier(i, CARRIER, 0x04);
+		opl2.setAttack    (i, CARRIER, 0x0A);
+		opl2.setDecay     (i, CARRIER, 0x04);
+		opl2.setSustain   (i, CARRIER, 0x08);
+		opl2.setRelease   (i, CARRIER, 0x04);
+		opl2.setVolume    (i, CARRIER, 0x00);
+		opl2.setWaveForm  (i, CARRIER, 0x00);
+		opl2.setMaintainSustain(i, CARRIER, false);
+	}
+}
+
+
+void loop() {
+	if (Serial.available() > 0 ) {
+		byte data = Serial.read();
+
+		// Is this a MIDI status?
+		if (data & 0x80) {
+
+			// Handle system exclusive data.
+			if (data == MIDI_SYSEX_START) {
+				handleSysExEvent();
+
+			// For other MIDI statuses extract command, channel and perapre to receive data.
+			} else {
+				midiCommand = data & 0xF0;
+				midiChannel = data & 0x0F;
+				midiDataIndex = 0;
+				midiDataBytes = 2;
+				if (midiCommand == MIDI_PROGRAM_CHANGE || midiCommand == MIDI_CHANNEL_AFTERTOUCH) {
+					midiDataBytes = 1;
+				}
+			}
+
+		// Receive MIDI data.
+		} else {
+			midiData[midiDataIndex] = (data & 0x7F);
+			midiDataIndex ++;
+
+			// If all data for the MIDI command is received then handle it!
+			if (midiDataIndex == midiDataBytes) {
+				handleMidiEvent();
+				midiDataIndex = 0;
+			}
+		}
+	}
+}
+
+
+/**
+ * Handle the current MIDI status.
+ */
+void handleMidiEvent() {
+	switch (midiCommand) {
+		case MIDI_NOTE_ON:
+			playNote();
+			break;
+		case MIDI_NOTE_OFF:
+			stopNote();
+			break;
+		case MIDI_POLY_AFTERTOUCH:
+			break;
+		case MIDI_CONTROL_CHANGE:
+			changeControl();
+			break;
+		case MIDI_PROGRAM_CHANGE:
+			break;
+		case MIDI_CHANNEL_AFTERTOUCH:
+			break;
+		default:
+			break;
+	}
+}
+
+
+/**
+ * Do not handle any system exclusive events. Just wait until the end of the system exclusive structure.
+ */
+void handleSysExEvent() {
+	byte data = 0x00;
+	while (data != MIDI_SYSEX_END) {
+		if (Serial.available()) {
+			data = Serial.read();
+		}
+	}
+}
+
+
+/**
+ * Play a note on the next available OPL2 channel.
+ */
+void playNote() {
+	byte note = midiData[0];
+	byte velocity = midiData[1];
+
+	// Register which note is playing on which channel.
+	oplNotes[oplChannel] = note;
+
+	// Adjust note to valid range and extract octave.
+	note = max(24, min(note, 119));
+	byte octave = 1 + (note - 24) / 12;
+	note = note % 12;
+	opl2.playNote(oplChannel, octave, note);
+
+	// Set OPL2 channel for the next note.
+	oplChannel = (oplChannel + 1) % NUM_OPL2_CHANNELS;
+}
+
+
+/**
+ * Stop playing a note by looking up its OPL2 channel and releasing the key.
+ */
+void stopNote() {
+	byte note = midiData[0];
+	byte velocity = midiData[1];
+
+	for (byte i = 0; i < NUM_OPL2_CHANNELS; i ++) {
+		if (oplNotes[i] == note) {
+			oplNotes[i] = NO_NOTE;
+			opl2.setKeyOn(1, false);
+		}
+	}
+}
+
+
+/**
+ * Change some of the carrier properties on control changes. Here the control's channel is used to pick the property to
+ * change. If it's more convenient to use the actual control numbers from your MIDI controller then use midiData[0] to
+ * get the control number.
+ */
+void changeControl() {
+	byte control = midiChannel;
+	// byte control = midiData[0];
+	byte value = midiData[1];
+	stopAll();
+
+	for (byte i = 0; i < NUM_OPL2_CHANNELS; i ++) {
+		switch (control) {
+			case 0:
+				opl2.setAttack(i, CARRIER, value);
+				break;
+			case 1:
+				opl2.setDecay(i, CARRIER, value);
+				break;
+			case 2:
+				opl2.setSustain(i, CARRIER, value);
+				break;
+			case 3:
+				opl2.setRelease(i, CARRIER, value);
+				break;
+			case 4:
+				opl2.setWaveForm(i, CARRIER, value);
+				break;
+			case 5:
+				opl2.setMultiplier(i, CARRIER, value);
+				break;
+			default:
+				break;
+		}
+	}
+}
+
+
+/**
+ * Immediately stop playing notes on all OPL2 channels when a control is changed.
+ */
+void stopAll() {
+	for (byte i = 0; i < NUM_OPL2_CHANNELS; i ++) {
+		opl2.setFNumber(i, 0);
+		opl2.setKeyOn(i, false);
+		oplNotes[i] = NO_NOTE;
+	}
+}

library.properties

@@ -1,5 +1,5 @@
 name=Arduino OPL2
-version=2.0.2
+version=2.0.3
 author=Maarten Janssen <maarten@cheerful.nl>
 maintainer=Maarten Janssen <maarten@cheerful.nl>
 sentence=Use this library to control the OPL2 Audio Board or OPL3 Duo!

src/OPL2.cpp

@@ -16,7 +16,7 @@
  *            \____|__  /__|  \____ |____/|__|___|  /\____/  \_____\ \  |____|   |__|
  *                    \/           \/             \/                \/
  *
- * YM3812 OPL2 Audio Library for Arduino, Raspberry Pi and Orange Pi v2.0.2
+ * YM3812 OPL2 Audio Library for Arduino, Raspberry Pi and Orange Pi v2.0.3
  * Code by Maarten Janssen (maarten@cheerful.nl) 2016-12-18
  * WWW.CHEERFUL.NL
  *
@@ -36,7 +36,7 @@
  * IMPORTANT: Make sure you set the correct BOARD_TYPE in OPL2.h. Default is set to Arduino.
  *
  *
- * Last updated 2020-10-31
+ * Last updated 2020-11-23
  * Most recent version of the library can be found at my GitHub: https://github.com/DhrBaksteen/ArduinoOPL2
  * Details about the YM3812 and YMF262 chips can be found at http://www.shikadi.net/moddingwiki/OPL_chip
  *