3.3.7

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

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+/*
+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"
+// Creates the MIDI device with specific descriptor
+USBMIDI MIDI("ESP MIDI Device");
+
+#define MIDI_NOTE_C4 60
+
+#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();
+  pinMode(BUTTON_PIN, INPUT_PULLUP);
+  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/MidiController/ci.yml

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+requires:
+  - CONFIG_SOC_USB_OTG_SUPPORTED=y