Add USB MIDI support to libraries/USB

CMakeLists.txt

@@ -115,6 +115,7 @@ set(LIBRARY_SRCS
   libraries/Update/src/Updater.cpp
   libraries/Update/src/HttpsOTAUpdate.cpp
   libraries/USB/src/USBHID.cpp
+  libraries/USB/src/USBMIDI.cpp
   libraries/USB/src/USBHIDMouse.cpp
   libraries/USB/src/USBHIDKeyboard.cpp
   libraries/USB/src/USBHIDGamepad.cpp

libraries/USB/examples/MIDI/MidiController/MidiController.ino

@@ -0,0 +1,118 @@
+/*
+This is an example of a Simple MIDI Controller using an ESP32 with a native USB support stack (S2, S3,
+etc.).
+
+For a hookup guide and more information on reading the ADC, please see:
+https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/ (Note: This sketch uses GPIO05)
+
+For best results, it is recommended to add an extra offset resistor between VCC and the potentiometer.
+(For a standard 10kOhm potentiometer, 3kOhm - 4kOhm will do.)
+
+View this sketch in action on YouTube: https://youtu.be/Y9TLXs_3w1M
+*/
+#if ARDUINO_USB_MODE
+#warning This sketch should be used when USB is in OTG mode
+void setup() {}
+void loop() {}
+#else
+
+#include <math.h>
+
+#include "USB.h"
+#include "USBMIDI.h"
+USBMIDI MIDI;
+
+#define MIDI_NOTE_C4 64
+
+#define MIDI_CC_CUTOFF 74
+
+///// ADC & Controller Input Handling /////
+
+#define CONTROLLER_PIN 5
+
+// ESP32 ADC needs a ton of smoothing
+#define SMOOTHING_VALUE 1000
+static double controllerInputValue = 0;
+
+void updateControllerInputValue() {
+    controllerInputValue =
+        (controllerInputValue * (SMOOTHING_VALUE - 1) + analogRead(CONTROLLER_PIN)) / SMOOTHING_VALUE;
+}
+
+void primeControllerInputValue() {
+    for (int i = 0; i < SMOOTHING_VALUE; i++) {
+        updateControllerInputValue();
+    }
+}
+
+uint16_t readControllerValue() {
+    // Lower ADC input amplitude to get a stable value
+    return round(controllerInputValue / 12);
+}
+
+///// Button Handling /////
+
+#define BUTTON_PIN 0
+
+// Simple button state transition function with debounce
+// (See also: https://tinyurl.com/simple-debounce)
+#define PRESSED 0xff00
+#define RELEASED 0xfe1f
+uint16_t getButtonEvent() {
+    static uint16_t state = 0;
+    state = (state << 1) | digitalRead(BUTTON_PIN) | 0xfe00;
+    return state;
+}
+
+///// Arduino Hooks /////
+
+void setup() {
+    Serial.begin(115200);
+    MIDI.begin();
+    USB.begin();
+
+    primeControllerInputValue();
+}
+
+void loop() {
+    uint16_t newControllerValue = readControllerValue();
+    static uint16_t lastControllerValue = 0;
+
+    // Auto-calibrate the controller range
+    static uint16_t maxControllerValue = 0;
+    static uint16_t minControllerValue = 0xFFFF;
+
+    if (newControllerValue < minControllerValue) {
+        minControllerValue = newControllerValue;
+    }
+    if (newControllerValue > maxControllerValue) {
+        maxControllerValue = newControllerValue;
+    }
+
+    // Send update if the controller value has changed
+    if (lastControllerValue != newControllerValue) {
+        lastControllerValue = newControllerValue;
+
+        // Can't map if the range is zero
+        if (minControllerValue != maxControllerValue) {
+            MIDI.controlChange(MIDI_CC_CUTOFF,
+                               map(newControllerValue, minControllerValue, maxControllerValue, 0, 127));
+        }
+    }
+
+    updateControllerInputValue();
+
+    // Hook Button0 to a MIDI note so that we can observe
+    // the CC effect without the need for a MIDI keyboard.
+    switch (getButtonEvent()) {
+        case PRESSED:
+            MIDI.noteOn(MIDI_NOTE_C4, 64);
+            break;
+        case RELEASED:
+            MIDI.noteOff(MIDI_NOTE_C4, 0);
+            break;
+        default:
+            break;
+    }
+}
+#endif /* ARDUINO_USB_MODE */

libraries/USB/examples/MIDI/MidiInterface/MidiInterface.ino

@@ -0,0 +1,70 @@
+/*
+This is an example of using an ESP32 with a native USB support stack (S2, S3, etc.) as a Serial MIDI to
+USB MIDI bridge (AKA "A MIDI Interface").
+
+View this sketch in action on YouTube: https://youtu.be/BXG5i55I9s0
+
+Receiving and decoding USB MIDI 1.0 packets is a more advanced topic than sending MIDI over USB,
+please refer to the other examples in this library for a more basic example of sending MIDI over USB.
+
+This example should still be self explanatory, please refer to the USB MIDI 1.0 specification (the spec)
+for a more in-depth explanation of the packet format.
+
+For the spec please visit: https://www.midi.org/specifications-old/item/usb-midi-1-0-specification
+
+Note: Because ESP32 works at VCC=3.3v normal schematics for Serial MIDI connections will not suffice,
+      Please refer to the Updated MIDI 1.1 Electrical Specification [1] for information on how to hookup
+      Serial MIDI for 3.3v devices.
+
+[1] - https://www.midi.org/specifications/midi-transports-specifications/5-pin-din-electrical-specs
+*/
+#if ARDUINO_USB_MODE
+#warning This sketch should be used when USB is in OTG mode
+void setup() {}
+void loop() {}
+#else
+
+#include "USB.h"
+#include "USBMIDI.h"
+USBMIDI MIDI;
+
+#define MIDI_RX 39
+#define MIDI_TX 40
+
+void setup() {
+    // USBCDC Serial
+    Serial.begin(115200);
+
+    // HW UART Serial
+    Serial1.begin(31250, SERIAL_8N1, MIDI_RX, MIDI_TX);
+
+    MIDI.begin();
+    USB.begin();
+}
+
+void loop() {
+    // MIDI Serial 1.0 to USB MIDI 1.0
+    if (Serial1.available()) {
+        byte data = Serial1.read();
+        MIDI.write(data);
+    }
+
+    // USB MIDI 1.0 to MIDI Serial 1.0
+    midiEventPacket_t midi_packet_in = {0};
+    // See Chapter 4: USB-MIDI Event Packets (page 16) of the spec.
+    int8_t cin_to_midix_size[16] = {-1, -1, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1};
+
+    if (MIDI.readPacket(&midi_packet_in)) {
+        midi_code_index_number_t code_index_num = MIDI_EP_HEADER_CIN_GET(midi_packet_in.header);
+        int8_t midix_size = cin_to_midix_size[code_index_num];
+
+        // We skip Misc and Cable Events for simplicity
+        if (code_index_num >= 0x2) {
+            for (int i = 0; i < midix_size; i++) {
+                Serial1.write(((uint8_t *)&midi_packet_in)[i + 1]);
+            }
+            Serial1.flush();
+        }
+    }
+}
+#endif /* ARDUINO_USB_MODE */

libraries/USB/examples/MIDI/MidiMusicBox/MidiMusicBox.ino

@@ -0,0 +1,59 @@
+/*
+This is an example of a MIDI Music Box using an ESP32 with a native USB support stack (S2, S3, etc.).
+
+Every time the button on the ESP32 board (attached to pin 0) is pressed the next note of a melody is
+played. It is up to the user to get the timing of the button presses right.
+
+One simple way of running this sketch is to download the Pianoteq evaluation version, because upon
+application start it automatically listens to the first MIDI Input on Channel 1, which is the case,
+if the ESP32 is the only MIDI device attached.
+
+View this sketch in action on YouTube: https://youtu.be/JFrc-wSmcus
+*/
+#if ARDUINO_USB_MODE
+#warning This sketch should be used when USB is in OTG mode
+void setup() {}
+void loop() {}
+#else
+
+#include "USB.h"
+#include "USBMIDI.h"
+USBMIDI MIDI;
+
+#define END_OF_SONG 255
+uint8_t notes[] = {END_OF_SONG, 71, 76, 79, 78, 76, 83, 81, 78, 76, 79, 78, 75, 77, 71};
+uint8_t noteIndex = 0; // From 0 to sizeof(notes)
+#define SONG_LENGTH (sizeof(notes) - 1) // END_OF_SONG does not attribute to the length.
+
+#define BUTTON_PIN 0
+
+// Simple button press check with debounce
+// (See also: https://tinyurl.com/simple-debounce)
+bool isButtonPressed() {
+    static uint16_t state = 0;
+    state = (state << 1) | digitalRead(BUTTON_PIN) | 0xfe00;
+    return (state == 0xff00);
+}
+
+void setup() {
+    Serial.begin(115200);
+    // Make the BUTTON_PIN an input:
+    pinMode(BUTTON_PIN, INPUT_PULLUP);
+
+    MIDI.begin();
+    USB.begin();
+}
+
+void loop() {
+    if (isButtonPressed()) {
+        // Stop current note
+        MIDI.noteOff(notes[noteIndex]);
+
+        // Play next note
+        noteIndex = noteIndex < SONG_LENGTH ? noteIndex + 1 : 0;
+        if (notes[noteIndex] != END_OF_SONG) {
+            MIDI.noteOn(notes[noteIndex], 64);
+        }
+    }
+}
+#endif /* ARDUINO_USB_MODE */

libraries/USB/examples/MIDI/ReceiveMidi/ReceiveMidi.ino

@@ -0,0 +1,104 @@
+/*
+This is an example of receiving USB MIDI 1.0 messages using an ESP32 with a native USB support stack
+(S2, S3, etc.).
+
+Receiving and decoding USB MIDI 1.0 packets is a more advanced topic than sending MIDI over USB,
+please refer to the other examples in this library for a more basic example of sending MIDI over USB.
+
+This example should still be self explanatory, please refer to the USB MIDI 1.0 specification (the spec)
+for a more in-depth explanation of the packet format.
+
+For the spec please visit: https://www.midi.org/specifications-old/item/usb-midi-1-0-specification
+*/
+#if ARDUINO_USB_MODE
+#warning This sketch should be used when USB is in OTG mode
+void setup() {}
+void loop() {}
+#else
+
+#include "USB.h"
+#include "USBMIDI.h"
+USBMIDI MIDI;
+
+void setup() {
+    Serial.begin(115200);
+
+    MIDI.begin();
+    USB.begin();
+}
+
+void loop() {
+    midiEventPacket_t midi_packet_in = {0};
+
+    if (MIDI.readPacket(&midi_packet_in)) {
+        printDetails(midi_packet_in);
+    }
+}
+
+void printDetails(midiEventPacket_t &midi_packet_in) {
+    // See Chapter 4: USB-MIDI Event Packets (page 16) of the spec.
+    uint8_t cable_num = MIDI_EP_HEADER_CN_GET(midi_packet_in.header);
+    midi_code_index_number_t code_index_num = MIDI_EP_HEADER_CIN_GET(midi_packet_in.header);
+
+    Serial.println("Received a USB MIDI packet:");
+    Serial.println(".----.-----.--------.--------.--------.");
+    Serial.println("| CN | CIN | STATUS | DATA 0 | DATA 1 |");
+    Serial.println("+----+-----+--------+--------+--------+");
+    Serial.printf("| %d  |  %X  |   %X   |   %X   |   %X   |\n", cable_num, code_index_num,
+                  midi_packet_in.byte1, midi_packet_in.byte2, midi_packet_in.byte3);
+    Serial.println("'----'-----'--------.--------'--------'\n");
+    Serial.print("Description: ");
+
+    switch (code_index_num) {
+        case MIDI_CIN_MISC:
+            Serial.println("This a Miscellaneous event");
+            break;
+        case MIDI_CIN_CABLE_EVENT:
+            Serial.println("This a Cable event");
+            break;
+        case MIDI_CIN_SYSCOM_2BYTE: // 2 byte system common message e.g MTC, SongSelect
+        case MIDI_CIN_SYSCOM_3BYTE: // 3 byte system common message e.g SPP
+            Serial.println("This a System Common (SysCom) event");
+            break;
+        case MIDI_CIN_SYSEX_START:     // SysEx starts or continue
+        case MIDI_CIN_SYSEX_END_1BYTE: // SysEx ends with 1 data, or 1 byte system common message
+        case MIDI_CIN_SYSEX_END_2BYTE: // SysEx ends with 2 data
+        case MIDI_CIN_SYSEX_END_3BYTE: // SysEx ends with 3 data
+            Serial.println("This a system exclusive (SysEx) event");
+            break;
+        case MIDI_CIN_NOTE_ON:
+            Serial.printf("This a Note-On event of Note %d with a Velocity of %d\n",
+                          midi_packet_in.byte2, midi_packet_in.byte3);
+            break;
+        case MIDI_CIN_NOTE_OFF:
+            Serial.printf("This a Note-Off event of Note %d with a Velocity of %d\n",
+                          midi_packet_in.byte2, midi_packet_in.byte3);
+            break;
+        case MIDI_CIN_POLY_KEYPRESS:
+            Serial.printf("This a Poly Aftertouch event for Note %d and Value %d\n",
+                          midi_packet_in.byte2, midi_packet_in.byte3);
+            break;
+        case MIDI_CIN_CONTROL_CHANGE:
+            Serial.printf("This a Control Change/Continuous Controller (CC) event of Controller %d "
+                          "with a Value of %d\n",
+                          midi_packet_in.byte2, midi_packet_in.byte3);
+            break;
+        case MIDI_CIN_PROGRAM_CHANGE:
+            Serial.printf("This a Program Change event with a Value of %d\n", midi_packet_in.byte2);
+            break;
+        case MIDI_CIN_CHANNEL_PRESSURE:
+            Serial.printf("This a Channel Pressure event with a Value of %d\n", midi_packet_in.byte2);
+            break;
+        case MIDI_CIN_PITCH_BEND_CHANGE:
+            Serial.printf("This a Pitch Bend Change event with a Value of %d\n",
+                          ((uint16_t)midi_packet_in.byte2) << 7 | midi_packet_in.byte3);
+            break;
+        case MIDI_CIN_1BYTE_DATA:
+            Serial.printf("This an embedded Serial MIDI event byte with Value %X\n",
+                          midi_packet_in.byte1);
+            break;
+    }
+
+    Serial.println();
+}
+#endif /* ARDUINO_USB_MODE */