teensymoog/minimoog_teensy/minimoog_teensy.ino

// Minimoog - Teensy
/*
 * This program is part of a minimoog-like synthesizer based on teensy 4.0
 * Copyright (C) 2020  Pierre-Loup Martin
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/* This program is a synthesizer very similar to the minimoog model D.
 * It is intended to run on a Teensy 4.0, using the PJRC audio library.
 * It also uses two Arduino Mega boards to manage all the user inputs :
 * keyboard, switches, potentiometers, etc.
 * All user inputs are handled and send to the teensy board using midi commands
 */

 /*
  * Pinout
  *
  * RX from mega 1 (through tension divider) 		0
  * TX to mega 1 (serial 1)							1
  * mega 1 reset 									2
  * 	
  * RX from mega 2 (through tension divider) 		16
  * TX to mega 2 (serial 4)							17
  * mega 2 reset 									18
  * 	
  * I2S OUT1A 										7
  * I2S LRCLK1										20
  * I2S BCLK1 										21
  *
  * D+ & D- are also used to break the USB port to the rear panel
  */

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

#include "audio_setup.h"
#include "defs.h"

#include "MIDI.h"

// constants
const uint8_t KEYTRACK_MAX = 10;

const uint8_t MAX_OCTAVE = 10;
const uint8_t FILTER_MAX_OCTAVE = 5;

const float NOTE_MIDI_0 = 8.1757989156434;
const float NOTE_RATIO = 1.0594630943593;

const float HALFTONE_TO_DC = (float)1 / (MAX_OCTAVE * 12);
const float FILTER_HALFTONE_TO_DC = (float)1 / (FILTER_MAX_OCTAVE * 12);

const float FILTER_BASE_FREQUENCY = 440.0;
const float FILTER_BASE_NOTE = (log(FILTER_BASE_FREQUENCY / NOTE_MIDI_0)) / (log(NOTE_RATIO));

const float MAX_MIX = 1.0;

const uint16_t RESO = 1024;
const uint16_t HALF_RESO = RESO / 2;

const int16_t PITCH_BEND_MIN = -168;
const int16_t PITCH_BEND_MAX = 134;
const int16_t PITCH_BEND_NEUTRAL = PITCH_BEND_MIN + (PITCH_BEND_MAX - PITCH_BEND_MIN) / 2;
const int16_t PITCH_BEND_COURSE = PITCH_BEND_MAX - PITCH_BEND_MIN;

const uint16_t MOD_WHEEL_MIN = 360;
const uint16_t MOD_WHEEL_MAX = 666;
const uint16_t MOD_WHEEL_NEUTRAL = MOD_WHEEL_MIN + (MOD_WHEEL_MAX - MOD_WHEEL_MIN) / 2;
const uint16_t MOD_WHEEL_COURSE = MOD_WHEEL_MAX - MOD_WHEEL_MIN;

const uint8_t MEGA1_RST = 2;
const uint8_t MEGA2_RST = 18;

// variables

uint8_t midiChannel = 1;

uint16_t glide = 0;
bool glideEn  = 0;

bool noteRetrigger = 1;

bool filterKeyTrack1 = 0;
bool filterKeyTrack2 = 0;

int8_t transpose = 0;
bool function = 0;

bool oscMod = 0;
bool decay = 0;

float filterDecay = 0;
float egDecay = 0;

// Waveforms
uint8_t waveforms[6] = {WAVEFORM_SINE, WAVEFORM_TRIANGLE, WAVEFORM_SAWTOOTH,
						WAVEFORM_SAWTOOTH_REVERSE, WAVEFORM_SQUARE, WAVEFORM_PULSE};

// keyTrack
uint8_t keyTrackIndex = 0;
uint8_t keyTrack[KEYTRACK_MAX] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

// double CC track
uint8_t ccTempValue[32];

enum keyMode_t{
	KEY_FIRST = 0,
	KEY_LAST,
	KEY_LOWER,
	KEY_UPPER,
};

keyMode_t keyMode = KEY_LAST;

struct midiSettings : public midi::DefaultSettings{
//	static const bool UseRunningStatus = true;
	static const long BaudRate = 115200;
};

// The one we use on synth
MIDI_CREATE_CUSTOM_INSTANCE(HardwareSerial, Serial1, midi1, midiSettings);
MIDI_CREATE_CUSTOM_INSTANCE(HardwareSerial, Serial4, midi2, midiSettings);


void setup() {

	// Mega resets
	pinMode(MEGA1_RST, OUTPUT);
	pinMode(MEGA2_RST, OUTPUT);
	digitalWrite(MEGA1_RST, 0);
	digitalWrite(MEGA2_RST, 0);

	// midi settings, start and callback
	midi1.begin(1);
	midi1.turnThruOff();
	midi1.setHandleNoteOn(handleNoteOn);
	midi1.setHandleNoteOff(handleNoteOff);
	midi1.setHandlePitchBend(handlePitchBend);
	midi1.setHandleControlChange(handleControlChange);

	midi2.begin(1);
	midi2.turnThruOff();
	midi2.setHandleControlChange(handleControlChange);

/*
	Serial.begin(115200);
	Serial.println("started...");
*/
	AudioMemory(200);

	digitalWrite(MEGA1_RST, 1);
	digitalWrite(MEGA2_RST, 1);
	delay(500);

	midi1.sendControlChange(CC_ASK_FOR_DATA, 127, 1);
	midi2.sendControlChange(CC_ASK_FOR_DATA, 127, 1);

	// audio settings
	// dc
	dcKeyTrack.amplitude(0.0);
	dcPitchBend.amplitude(0.0);
	dcFilterEnvelope.amplitude(1.0);
	dcFilter.amplitude(0.0);
	dcFilterKeyTrack.amplitude(0.0);
	dcOsc3.amplitude(0.2);
	dcLfoFreq.amplitude(0.0);
	dcOscTune.amplitude(0.0);
	dcOsc2Tune.amplitude(0.0);
	dcOsc3Tune.amplitude(0.0);
	dcPulse.amplitude(-0.95);

	// amp
	ampPitchBend.gain(3 * HALFTONE_TO_DC * 2);
	ampModWheel.gain(0.0);
	ampPreFilter.gain(1.0);
	ampModEg.gain(0.1);
	ampOsc3Mod.gain(1);

	osc1Waveform.frequencyModulation(MAX_OCTAVE);
	osc2Waveform.frequencyModulation(MAX_OCTAVE);
	osc3Waveform.frequencyModulation(MAX_OCTAVE);
	osc1Waveform.begin(1, NOTE_MIDI_0, WAVEFORM_TRIANGLE);
	osc2Waveform.begin(1, NOTE_MIDI_0, WAVEFORM_SAWTOOTH);
	osc3Waveform.begin(1, NOTE_MIDI_0, WAVEFORM_SQUARE);

	// noise
	whiteNoise.amplitude(1);
	pinkNoise.amplitude(1);

	// LFO
	lfoWaveform.begin(1, 0.1, WAVEFORM_TRIANGLE);
	lfoWaveform.frequencyModulation(11);

	// mixers
	mainTuneMixer.gain(0, 1);
	mainTuneMixer.gain(1, 1);
	mainTuneMixer.gain(2, 1);
	mainTuneMixer.gain(3, 1);
	osc2TuneMixer.gain(0, 1);
	osc2TuneMixer.gain(1, 1);
	osc3TuneMixer.gain(0, 1);
	osc3TuneMixer.gain(1, 1);

	oscMixer.gain(0, 1);
	oscMixer.gain(1, 0);
	oscMixer.gain(2, 0);
	oscMixer.gain(3, 0);

	globalMixer.gain(0, 1);
	globalMixer.gain(1, 0);

	noiseMixer.gain(0, 1);
	noiseMixer.gain(1, 0);

	osc3ControlMixer.gain(0, 1);
	osc3ControlMixer.gain(1, 0);

	modMix1.gain(0, 0);
	modMix1.gain(1, 1);
	modMix2.gain(0, 1);
	modMix2.gain(1, 0);
	modMixer.gain(0, 1);
	modMixer.gain(1, 0);

	filterMixer.gain(0, 0);
	filterMixer.gain(1, 0);
	filterMixer.gain(2, 1);
	filterMixer.gain(3, 0);

	bandMixer.gain(0, 1);
	bandMixer.gain(1, 0);

	// filter
	vcf.frequency(FILTER_BASE_FREQUENCY);
	vcf.resonance(0.7);
	vcf.octaveControl(FILTER_MAX_OCTAVE);

	// envelopes
	mainEnvelope.delay(0);
	mainEnvelope.attack(10);
	mainEnvelope.hold(0);
	mainEnvelope.decay(25);
	mainEnvelope.sustain(0.9);
	mainEnvelope.release(100);

	filterEnvelope.delay(0);
	filterEnvelope.attack(200);
	filterEnvelope.hold(0);
	filterEnvelope.decay(100);
	filterEnvelope.sustain(0.8);
	filterEnvelope.release(50);

	bitCrushOutput.bits(16);
	bitCrushOutput.sampleRate(44100.0);

	delay(500);

	midi1.sendControlChange(CC_ASK_FOR_DATA, 127, 1);
	midi2.sendControlChange(CC_ASK_FOR_DATA, 127, 1);

}

void loop() {
	midi1.read();
	midi2.read();
}

void noteOn(uint8_t note, uint8_t velocity, bool trigger = 1){
	float duration = (float)glideEn * (float)glide * 3.75;
	float level = ((float)note + 12 * transpose) * HALFTONE_TO_DC;
	float filterLevel = (((float)note - FILTER_BASE_NOTE) + (12 * transpose)) * FILTER_HALFTONE_TO_DC;

	AudioNoInterrupts();
	dcKeyTrack.amplitude(level, duration);
	dcFilterKeyTrack.amplitude(filterLevel, duration);
	if(trigger){
		filterEnvelope.noteOn();
		mainEnvelope.noteOn();
	}
	AudioInterrupts();
}

void noteOff(){
	AudioNoInterrupts();
	filterEnvelope.noteOff();
	mainEnvelope.noteOff();
	AudioInterrupts();
}

int8_t keyTrackAddNote(uint8_t note){
	// We only keep count of a limited quantity of notes !
	if (keyTrackIndex >= KEYTRACK_MAX) return -1;

	keyTrack[keyTrackIndex] = note;
	return keyTrackIndex++;
}

int8_t keyTrackRemoveNote(uint8_t note){
	int8_t update = -1;
	for(uint8_t i = 0; i < keyTrackIndex; ++i){
		if(keyTrack[i] == note){
			update = i;
			keyTrackIndex--;
			break;
		}
	}

	if(update >= 0){
		for(uint8_t i = update; i < keyTrackIndex; ++i){
			keyTrack[i] = keyTrack[i + 1];
		}
	}

	return update;
}

void handleNoteOn(uint8_t channel, uint8_t note, uint8_t velocity){
/*
	Serial.print("note ");
	Serial.print(note);
	Serial.println(" on");
*/
	switch(keyMode){
		// When KEY_FIRST, we play the note only if there is not one already playing
		case KEY_FIRST:
			if(keyTrackIndex != 0) return;
			keyTrack[0] = note;
			keyTrackIndex = 1;
			noteOn(note, velocity);
//			if(keyTrackAddNote(note) == 0) noteOn(note, velocity);
			break;
		// When KEY_LAST, we play the new note anyway.
		case KEY_LAST:
			keyTrack[0] = note;
			if(keyTrackIndex != 0){
				noteOn(note, velocity, noteRetrigger);
			} else {
				noteOn(note, velocity);
			}
			keyTrackIndex = 1;
//			if(keyTrackAddNote(note) == (keyTrackIndex - 1)) noteOn(note, velocity);
			break;
		case KEY_LOWER:
		case KEY_UPPER:
		default:
			break;
	}

}

void handleNoteOff(uint8_t channel, uint8_t note, uint8_t velocity){
/*
	Serial.print("note ");
	Serial.print(note);
	Serial.println(" off");
*/
	switch(keyMode){
		case KEY_FIRST:
/*			if(keyTrackRemoveNote(note) == 0){
				noteOff();
			}
			break;
*/		case KEY_LAST:
			if(keyTrack[0] == note){
				keyTrackIndex = 0;
				noteOff();
			}
/*			if(keyTrackRemoveNote(note) == keyTrackIndex){
				noteOff();
			}
*/			break;			
		case KEY_LOWER:
		case KEY_UPPER:
		default:
			break;
	}

}

void handlePitchBend(uint8_t channel, int16_t bend){
	dcPitchBend.amplitude(((float)bend - PITCH_BEND_NEUTRAL) / PITCH_BEND_COURSE);
	// Pitch bend goes from -168 to 134.
	// neutral at -11 from up, -24 from down. :/
/*
	Serial.print("pitch bend :");
	Serial.println(bend);
*/
}

void handleControlChange(uint8_t channel, uint8_t command, uint8_t value){
/*
	Serial.print("control change ");
	Serial.println(command);
*/
	uint16_t longValue = 0;
	if(command < 32){
		ccTempValue[command] = value;
/*
		Serial.print("value : ");
		Serial.print(value << 7);
		Serial.print(" (sent : ");
		Serial.print(value);
		Serial.println(')');
*/
	} else if(command < 64){
		longValue = (uint16_t)ccTempValue[command - 32];
		longValue <<= 7;
		longValue += value;
/*
		Serial.print("value : ");
		Serial.print(longValue);
		Serial.print(" (sent : ");
		Serial.print(value);
		Serial.println(')');
*/
	} else {
/*
		Serial.print("value : ");
		Serial.println(value);		
*/
	}
	switch(command){
		case CC_MOD_WHEEL:
		// CC_1
			break;
		case CC_MODULATION_MIX:
		// CC_3
			break;
		case CC_PORTAMENTO_TIME:
		// CC_5
			break;
		case CC_OSC_TUNE:
		// CC_9
			break;
		case CC_OSC2_TUNE:
		// CC_12
			break;
		case CC_OSC3_TUNE:
		// CC_13
			break;
		case CC_OSC1_MIX:
		// CC_14
			break;
		case CC_OSC2_MIX:
		// CC_15
			break;
		case CC_OSC3_MIX:
		// CC_16
			break;
		case CC_NOISE_MIX:
		// CC_17
			break;
		case CC_FEEDBACK_MIX:
		// CC_18
			break;
		case CC_FILTER_BAND:
		// CC_19
			break;
		case CC_FILTER_CUTOFF_FREQ:
		// CC_20
//			vcf.frequency((float)value * 32);
			break;
		case CC_FILTER_EMPHASIS:
		// CC_21
			break;
		case CC_FILTER_CONTOUR:
		// CC_22
			break;
		case CC_FILTER_ATTACK:
		// CC_23
			break;
		case CC_FILTER_DECAY:
		// CC_24
			break;
		case CC_FILTER_SUSTAIN:
		// CC_25
			break;
		case CC_FILTER_RELEASE:
		// CC_26
			break;
		case CC_EG_ATTACK:
		// CC_27
			break;
		case CC_EG_DECAY:
		// CC_28
			break;
		case CC_EG_SUSTAIN:
		// CC_29
			break;
		case CC_LFO_RATE:
		// CC_31
			break;
		case CC_MOD_WHEEL_LSB:
		// CC_33
			ampModWheel.gain(((float)longValue - 1 - MOD_WHEEL_MIN) / 12 / MOD_WHEEL_COURSE);
			// Mod wheel goes from 360 to 666.
/*
			Serial.print("mod wheel : ");
			Serial.println(longValue);
*/
			break;
		case CC_MODULATION_MIX_LSB:
		// CC_35
			AudioNoInterrupts();
			modMixer.gain(0, (float)longValue / RESO);
			modMixer.gain(1, (RESO - (float)longValue) / RESO);
			AudioInterrupts();
			break;
		case CC_PORTAMENTO_TIME_LSB:
		// CC_37
			glide = longValue;
			break;
		case CC_OSC_TUNE_LSB:
		// CC_41
			dcOscTune.amplitude(HALFTONE_TO_DC * 2 * ((float)longValue - HALF_RESO) / RESO);
			break;
		case CC_OSC2_TUNE_LSB:
		// CC_44
			dcOsc2Tune.amplitude(HALFTONE_TO_DC * 12 * 2 * ((float)longValue - HALF_RESO) / RESO);
			break;
		case CC_OSC3_TUNE_LSB:
		// CC_45
			dcOsc3Tune.amplitude(HALFTONE_TO_DC * 12 * 2 * ((float)longValue - HALF_RESO) / RESO);
			break;
		case CC_OSC1_MIX_LSB:
		// CC_46
			oscMixer.gain(0, MAX_MIX * (float)longValue / RESO);
			break;
		case CC_OSC2_MIX_LSB:
		// CC_47
			oscMixer.gain(1, MAX_MIX * (float)longValue / RESO);
			break;
		case CC_OSC3_MIX_LSB:
		// CC_48
			oscMixer.gain(2, MAX_MIX * (float)longValue / RESO);
			break;
		case CC_NOISE_MIX_LSB:
		// CC_49
			oscMixer.gain(3, MAX_MIX * (float)longValue / RESO);
			break;
		case CC_FEEDBACK_MIX_LSB:
		// CC_50
			globalMixer.gain(1, MAX_MIX * (float)longValue / RESO);
			break;
		case CC_FILTER_BAND_LSB:
		// CC_51
			AudioNoInterrupts();
			bandMixer.gain(0, ((float)longValue - RESO) / RESO);
			bandMixer.gain(1, (float)longValue / RESO);
			AudioInterrupts();
			break;
		case CC_FILTER_CUTOFF_FREQ_LSB:
		// CC_52
			dcFilter.amplitude(((float)longValue - HALF_RESO) / HALF_RESO);
			break;
		case CC_FILTER_EMPHASIS_LSB:
		// CC_53
			vcf.resonance(0.7 + (float)longValue / 237.90);
			break;
		case CC_FILTER_CONTOUR_LSB:
		// CC_54
			filterMixer.gain(1, (float)longValue / RESO);
			break;
		case CC_FILTER_ATTACK_LSB:
		// CC_55
			filterEnvelope.attack((float)longValue * 5.0);
			break;
		case CC_FILTER_DECAY_LSB:
		// CC_56
			filterEnvelope.decay((float)longValue * 5.0);
			break;
		case CC_FILTER_SUSTAIN_LSB:
		// CC_57
			filterEnvelope.sustain((float)longValue / RESO);
			break;
		case CC_FILTER_RELEASE_LSB:
		// CC_58
			filterEnvelope.release((float)longValue * 5.0);
			break;
		case CC_EG_ATTACK_LSB:
		// CC_59
			mainEnvelope.attack((float)longValue * 5.0);
			break;
		case CC_EG_DECAY_LSB:
		// CC_60
			mainEnvelope.decay((float)longValue * 5.0);
			break;
		case CC_EG_SUSTAIN_LSB:
		// CC_61
			mainEnvelope.sustain((float)longValue / RESO);
			break;
		case CC_EG_RELEASE_LSB:
		// CC_62
			mainEnvelope.release((float)longValue * 5.0);
			break;
		case CC_LFO_RATE_LSB:
		// CC_63
			dcLfoFreq.amplitude((float)longValue / RESO);
			break;
		case CC_PORTAMENTO_ON_OFF:
		// CC_65
			if(value < 64){
				glideEn = 1;
			} else {
				glideEn = 0;
			}
			break;
		case CC_BITCRUSH_OUT:
		// CC_91
			bitCrushOutput.bits(value);
			break;
		case CC_OSC1_RANGE:
		// CC_102
			osc1Waveform.frequency(NOTE_MIDI_0 / pow(2, value));
			break;
		case CC_OSC1_WAVEFORM:
		// CC_103
			osc1Waveform.begin(waveforms[value]);
			break;
		case CC_OSC2_RANGE:
		// CC_104
			osc2Waveform.frequency(NOTE_MIDI_0 / pow(2, value));
			break;
		case CC_OSC2_WAVEFORM:
		// CC_105
			osc2Waveform.begin(waveforms[value]);
			break;
		case CC_OSC3_RANGE:
		// CC_106
			osc3Waveform.frequency(NOTE_MIDI_0 / pow(2, value));
			break;
		case CC_OSC3_WAVEFORM:
		// CC_107
			osc3Waveform.begin(waveforms[value]);
			break;
		case CC_OSC3_CTRL:
		// CC_108
			AudioNoInterrupts();
			if(value > 63){
				osc3ControlMixer.gain(0, 1);
				osc3ControlMixer.gain(1, 0);
			} else {
				osc3ControlMixer.gain(0, 0);
				osc3ControlMixer.gain(1, 1);				
			}
			AudioInterrupts();
			break;
		case CC_FILTER_MOD:
		// CC_109
			if(value > 63){
				filterMixer.gain(0, 2);
			} else {
				filterMixer.gain(0, 0);
			}
			break;
		case CC_FILTER_KEYTRACK_1:
		// CC_110
			if(value > 63){
				filterKeyTrack1 = 1;
			} else {
				filterKeyTrack1 = 0;
			}
			filterMixer.gain(3, ((float)filterKeyTrack1 * 0.333333 + (float)filterKeyTrack2 * 0.666667));
			break;
		case CC_FILTER_KEYTRACK_2:
		// CC_111
			if(value > 63){
				filterKeyTrack2 = 1;
			} else {
				filterKeyTrack2 = 0;
			}
			filterMixer.gain(3, ((float)filterKeyTrack1 * 0.333333 + (float)filterKeyTrack2 * 0.666667));
			break;
		case CC_TRANSPOSE:
		// CC_112
			if(value > 63){
				transpose++;
				if (transpose > 2) transpose = 2;
			} else {
				transpose--;
				if(transpose < -2) transpose = -2;
			}
			break;
		case CC_FUNCTION:
		// CC_113
			if(value > 63){
				function = 1;
			} else {
				function = 0;
			}
			break;
		case CC_NOISE_COLOR:
		// CC_114
			AudioNoInterrupts();
			if(value > 0){
				noiseMixer.gain(0, 1);
				noiseMixer.gain(1, 0);
			} else {
				noiseMixer.gain(0, 0);
				noiseMixer.gain(1, 1);
			}
			AudioInterrupts();
			break;
		case CC_OSC_MOD:
		// CC_115
			if(value > 63){
				oscMod = 1;
				mainTuneMixer.gain(3, 1);
			} else {
				oscMod = 0;
				mainTuneMixer.gain(3, 0);
			}
			break;
/*
		case CC_DECAY_SW:
		// CC_116
			AudioNoInterrupts();
			if(value > 63){
				decay = 1;
				filterEnvelope.release(filterDecay);
				mainEnvelope.release(egDecay);
			} else {
				decay = 0;
				filterEnvelope.release(0.0);
				mainEnvelope.release(0.0);
			}
			AudioInterrupts();
			break;
*/
		case CC_MOD_MIX_1:
		// CC_117
			AudioNoInterrupts();
			if(value > 63){
				modMix1.gain(0, 0);
				modMix1.gain(1, 1);
			} else {
				modMix1.gain(0, 1);
				modMix1.gain(1, 0);
			}
			AudioInterrupts();
			break;
		case CC_MOD_MIX_2:
		// CC_118
			AudioNoInterrupts();
			if(value > 63){
				modMix2.gain(0, 0);
				modMix2.gain(1, 1);
			} else {
				modMix2.gain(0, 1);
				modMix2.gain(1, 0);
			}
			AudioInterrupts();
			break;
		case CC_LFO_SHAPE:
		// CC_119
			AudioNoInterrupts();
			if(value > 63){
				lfoWaveform.begin(WAVEFORM_TRIANGLE);
				lfoWaveform.offset(0.0);
				lfoWaveform.amplitude(1.0);
			} else {
				lfoWaveform.begin(WAVEFORM_SQUARE);
				lfoWaveform.offset(0.5);
				lfoWaveform.amplitude(0.5);
			}
			AudioInterrupts();
			break;
		default:
			break;
	}
}