Initial commit for midi. Midi out is working, Midi In is still a work in progress.

clock.h

@@ -12,28 +12,49 @@
 #ifndef CLOCK_H
 #define CLOCK_H
 
+#include <NeoHWSerial.h>
 #include <uClock.h>
 
 #include "peripherials.h"
 
+// MIDI clock, start, stop, and continue byte definitions - based on MIDI 1.0 Standards.
+#define MIDI_CLOCK 0xF8
+#define MIDI_START 0xFA
+#define MIDI_STOP 0xFC
+#define MIDI_CONTINUE 0xFB
+
 const int DEFAULT_TEMPO = 120;
+static bool MIDI_ENABLED = false;
 
 enum Source {
     SOURCE_INTERNAL,
     SOURCE_EXTERNAL_PPQN_24,
     SOURCE_EXTERNAL_PPQN_4,
-    // SOURCE_MIDI,
+    SOURCE_EXTERNAL_MIDI,
     SOURCE_LAST,
 };
 
 class Clock {
    public:
     void Init() {
+        NeoSerial.begin(31250);
+        NeoSerial.attachInterrupt(onSerialEvent);
+
+        // Static pin definition for pulse out.
+        pinMode(PULSE_OUT_PIN, OUTPUT);
+
         // Initialize the clock library
         uClock.init();
         uClock.setClockMode(uClock.INTERNAL_CLOCK);
         uClock.setOutputPPQN(uClock.PPQN_96);
         uClock.setTempo(DEFAULT_TEMPO);
+
+        // MIDI events.
+        uClock.setOnClockStart(sendMIDIStart);
+        uClock.setOnClockStop(sendMIDIStop);
+        uClock.setOnSync24(sendMidiClock);
+        uClock.setOnSync48(sendPulseOut);
+
         uClock.start();
     }
 
@@ -50,6 +71,7 @@ class Clock {
     // Set the source of the clock mode.
     void SetSource(Source source) {
         uClock.stop();
+        MIDI_ENABLED = false;
         switch (source) {
             case SOURCE_INTERNAL:
                 uClock.setClockMode(uClock.INTERNAL_CLOCK);
@@ -62,6 +84,11 @@ class Clock {
                 uClock.setClockMode(uClock.EXTERNAL_CLOCK);
                 uClock.setInputPPQN(uClock.PPQN_4);
                 break;
+            case SOURCE_EXTERNAL_MIDI:
+                uClock.setClockMode(uClock.EXTERNAL_CLOCK);
+                uClock.setInputPPQN(uClock.PPQN_24);
+                MIDI_ENABLED = true;
+                break;
         }
         uClock.start();
     }
@@ -97,6 +124,42 @@ class Clock {
     bool IsPaused() {
         return uClock.clock_state == uClock.PAUSED;
     }
+
+   private:
+    static void onSerialEvent(uint8_t msg, uint8_t status) {
+        // if (!MIDI_ENABLED) {
+        //     return;
+        // }
+        switch (msg) {
+            case MIDI_CLOCK:
+                uClock.clockMe();
+                break;
+            case MIDI_STOP:
+                uClock.stop();
+                break;
+            case MIDI_START:
+            case MIDI_CONTINUE:
+                uClock.start();
+                break;
+            
+        }
+    }
+
+    static void sendMIDIStart() {
+        NeoSerial.write(MIDI_START);
+    }
+
+    static void sendMIDIStop() {
+        NeoSerial.write(MIDI_STOP);
+    }
+
+    static void sendMidiClock(uint32_t tick) {
+        NeoSerial.write(MIDI_CLOCK);
+    }
+
+    static void sendPulseOut(uint32_t tick) {
+        digitalWrite(PULSE_OUT_PIN, !digitalRead(PULSE_OUT_PIN));
+    }
 };
 
 #endif

examples/clock_mod/clock_mod.ino

@@ -39,7 +39,7 @@ AppState app;
 
 // The number of clock mod options, hepls validate choices and pulses arrays are the same size.
 const int MOD_CHOICE_SIZE = 21;
-// negative=multiply, positive=divide
+// Negative for multiply, positive for divide.
 const int clock_mod[MOD_CHOICE_SIZE] = {-24, -12, -8, -6, -4, -3, -2, 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 24, 32, 64, 128};
 
 // This represents the number of clock pulses for a 96 PPQN clock source that match the above div/mult mods.
@@ -317,9 +317,14 @@ void DisplayMainPage() {
                 textWidth = gravity.display.getUTF8Width("4 PPQN");
                 gravity.display.drawStr(32 - (textWidth / 2), subTextY, "4 PPQN");
                 break;
-                // case SOURCE_EXTERNAL_MIDI:
-                //     gravity.display.print(F("EXT MIDI"));
-                //     break;
+            case SOURCE_EXTERNAL_MIDI:
+                gravity.display.setFont(LARGE_FONT);
+                textWidth = gravity.display.getUTF8Width("EXT");
+                gravity.display.drawStr(32 - (textWidth / 2), textY, "EXT");
+                gravity.display.setFont(TEXT_FONT);
+                textWidth = gravity.display.getUTF8Width("MIDI");
+                gravity.display.drawStr(32 - (textWidth / 2), subTextY, "MIDI");
+                break;
         }
     }
 
@@ -366,7 +371,7 @@ void DisplayChannelPage() {
                 gravity.display.drawStr(32 - (textWidth / 2), subTextY, "Divide");
 
             } else {
-                sprintf(mod_str, "X%d", abs(clock_mod[ch.clock_mod_index]));
+                sprintf(mod_str, "x%d", abs(clock_mod[ch.clock_mod_index]));
                 textWidth = gravity.display.getUTF8Width(mod_str);
                 gravity.display.drawStr(32 - (textWidth / 2), textY, mod_str);
                 gravity.display.setFont(TEXT_FONT);

peripherials.h

@@ -25,6 +25,7 @@
 #define EXT_PIN 2
 #define CV1_PIN A7
 #define CV2_PIN A6
+#define PULSE_OUT_PIN 3
 
 // Button pins
 #define SHIFT_BTN_PIN 12