From 3be85823c4f3cc375300ded60bbc4ba153358497 Mon Sep 17 00:00:00 2001
From: dougcl <dougcl@studiohsoftware.com>
Date: Sat, 12 Dec 2020 22:40:45 -0800
Subject: [PATCH 1/2] Add interrupt handler and example sketch.

---
 .../MIDIUSB_read_with_interrupts.ino          | 62 +++++++++++++++++++
 src/MIDIUSB.h                                 |  4 ++
 2 files changed, 66 insertions(+)
 create mode 100644 examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino

diff --git a/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino b/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino
new file mode 100644
index 0000000..8482e79
--- /dev/null
+++ b/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino
@@ -0,0 +1,62 @@
+/*
+ * MIDIUSB_test.ino
+ *
+ * Created: 4/6/2015 10:47:08 AM
+ * Author: gurbrinder grewal
+ * Modified by Arduino LLC (2015)
+ */ 
+
+#include "MIDIUSB.h"
+
+// First parameter is the event type (0x09 = note on, 0x08 = note off).
+// Second parameter is note-on/note-off, combined with the channel.
+// Channel can be anything between 0-15. Typically reported to the user as 1-16.
+// Third parameter is the note number (48 = middle C).
+// Fourth parameter is the velocity (64 = normal, 127 = fastest).
+
+void noteOn(byte channel, byte pitch, byte velocity) {
+  midiEventPacket_t noteOn = {0x09, 0x90 | channel, pitch, velocity};
+  MidiUSB.sendMIDI(noteOn);
+}
+
+void noteOff(byte channel, byte pitch, byte velocity) {
+  midiEventPacket_t noteOff = {0x08, 0x80 | channel, pitch, velocity};
+  MidiUSB.sendMIDI(noteOff);
+}
+
+void setup() {
+  Serial1.begin(115200);
+  MidiUSB.attachInterrupt(onEvent);
+}
+
+// First parameter is the event type (0x0B = control change).
+// Second parameter is the event type, combined with the channel.
+// Third parameter is the control number number (0-119).
+// Fourth parameter is the control value (0-127).
+
+void controlChange(byte channel, byte control, byte value) {
+  midiEventPacket_t event = {0x0B, 0xB0 | channel, control, value};
+  MidiUSB.sendMIDI(event);
+}
+
+void loop() {
+
+}
+
+void onEvent(int ep) {
+    USB->DEVICE.INTENCLR.reg = 0xFF; //SAMD interrupts continuously without this.
+    midiEventPacket_t rx;
+    do {
+      rx = MidiUSB.read();
+      if (rx.header != 0) {
+        Serial1.print("Received: ");
+        Serial1.print(rx.header, HEX);
+        Serial1.print("-");
+        Serial1.print(rx.byte1, HEX);
+        Serial1.print("-");
+        Serial1.print(rx.byte2, HEX);
+        Serial1.print("-");
+        Serial1.println(rx.byte3, HEX);
+      }
+    } while (rx.header != 0);
+}
diff --git a/src/MIDIUSB.h b/src/MIDIUSB.h
index 487eaea..f797e87 100644
--- a/src/MIDIUSB.h
+++ b/src/MIDIUSB.h
@@ -224,6 +224,8 @@ class MIDI_ : public PluggableUSBModule
   bool setup(USBSetup& setup);
   /// MIDI Device short name, defaults to "MIDI" and returns a length of 4 chars
   uint8_t getShortName(char* name);
+  void (*interruptCallback)(int /* ep */);
+  virtual void handleEndpoint(int ep) { if (interruptCallback) interruptCallback(ep); }
 
 public:
 	/// Creates a MIDI USB device with 2 endpoints
@@ -240,6 +242,8 @@ class MIDI_ : public PluggableUSBModule
 	size_t write(const uint8_t *buffer, size_t size);
 	/// NIY
 	operator bool();
+	void attachInterrupt(void(*function)(int /* ep */)){interruptCallback = function;};
+
 };
 extern MIDI_ MidiUSB;
 

From 74bb374ecbb72d92a52db2822eb7bb7b34a84d09 Mon Sep 17 00:00:00 2001
From: dougcl <dougcl@studiohsoftware.com>
Date: Sun, 13 Dec 2020 00:47:08 -0800
Subject: [PATCH 2/2] Add modification date to header.

---
 .../MIDIUSB_read_with_interrupts.ino                           | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino b/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino
index 8482e79..b59f86a 100644
--- a/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino
+++ b/examples/MIDIUSB_read_with_interrupts/MIDIUSB_read_with_interrupts.ino
@@ -1,6 +1,9 @@
 /*
  * MIDIUSB_test.ino
  *
+ * Modifed to use interrupts. 12/12/2020 
+ * Doug Clauder https://github.com/studiohsoftware
+ *
  * Created: 4/6/2015 10:47:08 AM
  * Author: gurbrinder grewal
  * Modified by Arduino LLC (2015)