Add USB MIDI support to libraries/USB (#8166)

* Added USBMIDI support to libraries/USB

* Added MIDI examples to libraries/USB

* Added missing newline at end of file to MidiController.ino

* Added USBMIDI.cpp to CMake file

* Fix narrowing conversion warning in USBMIDI.cpp

* Fix incomplete initializers warning in USBMIDI.cpp

* Apply suggestions from code review
Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>

* add skip files for C6+H2

* remove already patched workaroud for bug

* move #define to top of file

---------
Co-authored-by: Me No Dev <me-no-dev@users.noreply.github.com>
Co-authored-by: Lucas Saavedra Vaz <lucas.vaz@espressif.com>
Co-authored-by: Jan Procházka <90197375+P-R-O-C-H-Y@users.noreply.github.com>
Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>

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

+/*
+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

+/*
+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

+/*
+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

+/*
+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 */

libraries/USB/src/USBMIDI.cpp

+#include "USBMIDI.h"
+#if SOC_USB_OTG_SUPPORTED
+
+#if CONFIG_TINYUSB_MIDI_ENABLED
+
+#include "Arduino.h"
+#include "esp32-hal-tinyusb.h"
+
+// Default Cable Number (for simplified APIs that do not expose this)
+#define DEFAULT_CN 0
+
+static bool tinyusb_midi_descriptor_loaded = false;
+static bool tinyusb_midi_interface_enabled = false;
+
+extern "C" uint16_t tusb_midi_load_descriptor(uint8_t *dst, uint8_t *itf) {
+    if (tinyusb_midi_descriptor_loaded) {
+        return 0;
+    }
+    tinyusb_midi_descriptor_loaded = true;
+
+    uint8_t str_index = tinyusb_add_string_descriptor("TinyUSB MIDI");
+    uint8_t ep_in = tinyusb_get_free_in_endpoint();
+    TU_VERIFY(ep_in != 0);
+    uint8_t ep_out = tinyusb_get_free_out_endpoint();
+    TU_VERIFY(ep_out != 0);
+    uint8_t descriptor[TUD_MIDI_DESC_LEN] = {
+        TUD_MIDI_DESCRIPTOR(*itf, str_index, ep_out, (uint8_t)(0x80 | ep_in), 64),
+    };
+    *itf += 2;
+    memcpy(dst, descriptor, TUD_MIDI_DESC_LEN);
+
+    return TUD_MIDI_DESC_LEN;
+}
+
+USBMIDI::USBMIDI() {
+    if (!tinyusb_midi_interface_enabled) {
+        tinyusb_midi_interface_enabled = true;
+        tinyusb_enable_interface(USB_INTERFACE_MIDI, TUD_MIDI_DESC_LEN, tusb_midi_load_descriptor);
+    } else {
+        log_e("USBMIDI: Multiple instances of USBMIDI not supported!");
+    }
+}
+
+void USBMIDI::begin() {}
+void USBMIDI::end() {}
+
+// uint compatible version of constrain
+#define uconstrain(amt, low, high) ((amt) <= (low) ? (low) : ((amt) > (high) ? (high) : (amt)))
+
+#define STATUS(CIN, CHANNEL)                                                                           \
+    static_cast<uint8_t>(((CIN & 0x7F) << 4) | (uconstrain(CHANNEL - 1, 0, 15) & 0x7F))
+
+// Note: All the user-level API calls do extensive input constraining to prevent easy to make mistakes.
+// (You can thank me later.)
+#define _(x) static_cast<uint8_t>(uconstrain(x, 0, 127))
+
+// Note On
+void USBMIDI::noteOn(uint8_t note, uint8_t velocity, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_NOTE_ON, STATUS(MIDI_CIN_NOTE_ON, channel), _(note),
+                               _(velocity)};
+    writePacket(&event);
+}
+
+// Note Off
+void USBMIDI::noteOff(uint8_t note, uint8_t velocity, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_NOTE_OFF, STATUS(MIDI_CIN_NOTE_OFF, channel), _(note),
+                               _(velocity)};
+    writePacket(&event);
+}
+
+// Program Change
+void USBMIDI::programChange(uint8_t program, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_PROGRAM_CHANGE, STATUS(MIDI_CIN_PROGRAM_CHANGE, channel),
+                               _(program), 0x0};
+    writePacket(&event);
+}
+
+// Control Change (Continuous Controller)
+void USBMIDI::controlChange(uint8_t control, uint8_t value, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_CONTROL_CHANGE, STATUS(MIDI_CIN_CONTROL_CHANGE, channel),
+                               _(control), _(value)};
+    writePacket(&event);
+}
+
+// Polyphonic Key Pressure (Aftertouch)
+void USBMIDI::polyPressure(uint8_t note, uint8_t pressure, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_POLY_KEYPRESS, STATUS(MIDI_CIN_POLY_KEYPRESS, channel), _(note),
+                               _(pressure)};
+    writePacket(&event);
+}
+
+// Channel Pressure (Aftertouch)
+void USBMIDI::channelPressure(uint8_t pressure, uint8_t channel) {
+    midiEventPacket_t event = {MIDI_CIN_CHANNEL_PRESSURE, STATUS(MIDI_CIN_CHANNEL_PRESSURE, channel),
+                               _(pressure), 0x0};
+    writePacket(&event);
+}
+
+// Pitch Bend Change [-8192,0,8191]
+void USBMIDI::pitchBend(int16_t value, uint8_t channel) {
+    uint16_t pitchBendValue = constrain(value, -8192, 8191) + 8192;
+    pitchBend(pitchBendValue);
+}
+
+// Pitch Bend Change [0,8192,16383]
+void USBMIDI::pitchBend(uint16_t value, uint8_t channel) {
+    uint16_t pitchBendValue = static_cast<uint16_t>(uconstrain(value, 0, 16383));
+    // Split the 14-bit integer into two 7-bit values
+    uint8_t lsb = pitchBendValue & 0x7F;        // Lower 7 bits
+    uint8_t msb = (pitchBendValue >> 7) & 0x7F; // Upper 7 bits
+
+    midiEventPacket_t event = {MIDI_CIN_PITCH_BEND_CHANGE, STATUS(MIDI_CIN_PITCH_BEND_CHANGE, channel),
+                               lsb, msb};
+    writePacket(&event);
+}
+
+// Pitch Bend Change [-1.0,0,1.0]
+void USBMIDI::pitchBend(double value, uint8_t channel) {
+    // Multiply by 8191 and round to nearest integer
+    int16_t pitchBendValue = static_cast<int16_t>(round(constrain(value, -1.0, 1.0) * 8191.0));
+
+    pitchBend(pitchBendValue, channel);
+}
+
+bool USBMIDI::readPacket(midiEventPacket_t *packet) {
+    return tud_midi_packet_read((uint8_t *)packet);
+}
+
+bool USBMIDI::writePacket(midiEventPacket_t *packet) {
+    return tud_midi_packet_write((uint8_t *)packet);
+}
+
+size_t USBMIDI::write(uint8_t c) {
+    // MIDI_CIN_1BYTE_DATA => Verbatim MIDI byte-stream copy
+    // (See also Table 4-1 of USB MIDI spec 1.0)
+    midiEventPacket_t packet = {DEFAULT_CN | MIDI_CIN_1BYTE_DATA, c, 0, 0};
+
+    return tud_midi_packet_write((uint8_t *)&packet);
+}
+
+#endif /* CONFIG_TINYUSB_MIDI_ENABLED */
+#endif /* SOC_USB_OTG_SUPPORTED */

libraries/USB/src/USBMIDI.h

+#include "soc/soc_caps.h"
+#if SOC_USB_OTG_SUPPORTED
+#include "esp32-hal-tinyusb.h"
+#include "sdkconfig.h"
+
+#if CONFIG_TINYUSB_MIDI_ENABLED
+
+#pragma once
+
+#define MIDI_EP_HEADER_CN_GET(x) (x >> 4)
+#define MIDI_EP_HEADER_CIN_GET(x) ((midi_code_index_number_t)((x)&0xF))
+
+typedef struct {
+    uint8_t header;
+    uint8_t byte1;
+    uint8_t byte2;
+    uint8_t byte3;
+} midiEventPacket_t;
+
+class USBMIDI {
+public:
+    USBMIDI(void);
+    void begin(void);
+    void end(void);
+
+    /* User-level API */
+
+    // Note On
+    void noteOn(uint8_t note, uint8_t velocity = 0, uint8_t channel = 1);
+    // Note Off
+    void noteOff(uint8_t note, uint8_t velocity = 0, uint8_t channel = 1);
+    // Program Change
+    void programChange(uint8_t inProgramNumber, uint8_t channel = 1);
+    // Control Change (Continuous Controller)
+    void controlChange(uint8_t inControlNumber, uint8_t inControlValue = 0, uint8_t channel = 1);
+    // Polyphonic Key Pressure (Aftertouch)
+    void polyPressure(uint8_t note, uint8_t pressure, uint8_t channel = 1);
+    // Channel Pressure (Aftertouch)
+    void channelPressure(uint8_t pressure, uint8_t channel = 1);
+    // Pitch Bend Change [-8192,0,8191]
+    void pitchBend(int16_t pitchBendValue, uint8_t channel = 1);
+    // Pitch Bend Change [0,8192,16383]
+    void pitchBend(uint16_t pitchBendValue, uint8_t channel = 1);
+    // Pitch Bend Change [-1.0,0,1.0]
+    void pitchBend(double pitchBendValue, uint8_t channel = 1);
+
+    /* USB MIDI 1.0 interface */
+
+    // Attempt to read a USB MIDI packet from the USB Bus
+    bool readPacket(midiEventPacket_t *packet);
+    // Attempt to write a USB MIDI packet to the USB Bus
+    bool writePacket(midiEventPacket_t *packet);
+
+    /* Serial MIDI 1.0 interface */
+
+    // Write a Serial MIDI byte (status or data) to the USB Bus
+    size_t write(uint8_t c);
+};
+
+#endif /* CONFIG_TINYUSB_MIDI_ENABLED */
+#endif /* SOC_USB_OTG_SUPPORTED */