Custom-USB-MIDI-Backend.ino

Custom-USB-MIDI-Backend

This is an example that demonstrates how to extend the library using your own MIDI USB backend. It defines a class for sending and receiving raw MIDI USB packets that can be plugged into Control Surface's USBMIDI_Interface class.

See also

src/MIDI_Interfaces/USBMIDI/USBMIDI_Teensy3.hpp

src/MIDI_Interfaces/USBMIDI/USBMIDI_MIDIUSB.hpp

src/MIDI_Interfaces/USBMIDI/USBMIDI_Adafruit_TinyUSB.hpp

src/MIDI_Interfaces/USBHostMIDI_Interface.hpp

Boards: 🛈

AVR, AVR USB, Nano Every, Due, Nano 33 IoT, Nano 33 BLE, UNO R4, Pi Pico, Teensy 3.x, ESP32

Connections

None.

Behavior

• Prints the raw MIDI USB packets to the Serial Monitor.
• Receives no MIDI input.

Mapping

None.

Written by PieterP, 2022-05-28
https://github.com/tttapa/Control-Surface

 
#include <Control_Surface.h>
 
// This class defines how to send and receive MIDI data using your custom
// backend.
struct MyUSBMIDIBackend {
  // USB MIDI packages are 4 bytes.
  using MIDIUSBPacket_t = AH::Array<uint8_t, 4>;
  // This method is optional. It is called once upon initialization.
  void begin() { Serial.begin(115200); }
  // Read a single packet. Return a packet of all zeros if there is no packet.
  MIDIUSBPacket_t read() { return MIDIUSBPacket_t {}; }
  // Write a single packet to the output buffer.
  void write(MIDIUSBPacket_t p) { Serial << AH::HexDump(p.data) << endl; }
  // Transmit the output buffer immediately.
  void sendNow() { Serial.flush(); }
  // Should the sendNow method be called after each message? Return false if
  // your backend can send the data in the output buffer asynchronously and
  // automatically. Return true if that's not the case, and an explicit call to
  // sendNow is required.
  bool preferImmediateSend() { return false; }
};
 
// This is the actual MIDI interface that makes use of the backend defined above.
struct MyUSBMIDI_Interface : GenericUSBMIDI_Interface<MyUSBMIDIBackend> {
  MyUSBMIDI_Interface() = default;
  using MIDIUSBPacket_t = MyUSBMIDIBackend::MIDIUSBPacket_t;
};
 
// Instantiate the MIDI interface to use.
MyUSBMIDI_Interface midi;
 
void setup() {
  Control_Surface.begin();
}
 
void loop() {
  static Timer<millis> timer {1000};
  if (timer)
    // As an example, send a MIDI timing clock message every second.
    Control_Surface.sendRealTime(MIDIMessageType::TimingClock);
  Control_Surface.loop();
}