Introduce StateManager class for persisting state to EEPROM.

examples/Gravity/Gravity.ino

@@ -1,5 +1,5 @@
 /**
- * @file clock_mod.ino
+ * @file Gravity.ino
  * @author Adam Wonak (https://github.com/awonak/)
  * @brief Demo firmware for Sitka Instruments Gravity.
  * @version 0.1
@@ -18,20 +18,14 @@
  */
 
 #include <gravity.h>
-
+#include "save_state.h"
+#include "app_state.h"
 #include "channel.h"
 
-// Firmware state variables.
-struct AppState {
-    bool refresh_screen = true;
-    bool editing_param = false;
-    int selected_param = 0;
-    byte selected_channel = 0;  // 0=tempo, 1-6=output channel
-    Source selected_source = SOURCE_INTERNAL;
-    Channel channel[OUTPUT_COUNT];
-};
 AppState app;
 
+StateManager stateManager;
+
 enum ParamsMainPage {
     PARAM_MAIN_TEMPO,
     PARAM_MAIN_SOURCE,
@@ -114,6 +108,13 @@ void setup() {
     // Start Gravity.
     gravity.Init();
 
+    // Initialize the state manager. This will load settings from EEPROM
+    stateManager.initialize(app);
+
+    // Apply the loaded state to the hardware
+    gravity.clock.SetTempo(app.tempo);
+    gravity.clock.SetSource(app.selected_source);
+
     // Clock handlers.
     gravity.clock.AttachIntHandler(HandleIntClockTick);
     gravity.clock.AttachExtHandler(HandleExtClockTick);
@@ -192,6 +193,7 @@ void HandleShiftPressed() {
 
 void HandleEncoderPressed() {
     app.editing_param = !app.editing_param;
+    stateManager.save(app);
     app.refresh_screen = true;
 }
 
@@ -208,6 +210,7 @@ void HandleRotate(Direction dir, int val) {
             editChannelParameter(val);
         }
     }
+    stateManager.save(app);
     app.refresh_screen = true;
 }
 
@@ -218,6 +221,7 @@ void HandlePressedRotate(Direction dir, int val) {
         app.selected_channel--;
     }
     app.selected_param = 0;
+    stateManager.save(app);
     app.refresh_screen = true;
 }
 
@@ -228,6 +232,7 @@ void editMainParameter(int val) {
                 break;
             }
             gravity.clock.SetTempo(gravity.clock.Tempo() + val);
+            app.tempo = gravity.clock.Tempo();
             break;
 
         case PARAM_MAIN_SOURCE: {
@@ -357,6 +362,7 @@ void DisplayMainPage() {
                     subText = "MIDI";
                     break;
             }
+            break;            
     }
 
     drawCenteredText(mainText, MAIN_TEXT_Y, LARGE_FONT);

examples/Gravity/app_state.h

@@ -0,0 +1,18 @@
+#ifndef APP_STATE_H
+#define APP_STATE_H
+
+#include <gravity.h>
+#include "channel.h"
+
+// Global state for settings and app behavior.
+struct AppState {
+    int tempo = 120;
+    bool refresh_screen = true;
+    bool editing_param = false;
+    int selected_param = 0;
+    byte selected_channel = 0;  // 0=tempo, 1-6=output channel
+    Source selected_source = SOURCE_INTERNAL;
+    Channel channel[OUTPUT_COUNT];
+};
+
+#endif // APP_STATE_H

examples/Gravity/save_state.cpp

@@ -0,0 +1,85 @@
+// File: save_state.cpp
+
+#include <EEPROM.h>
+#include "save_state.h"
+#include "app_state.h" // Includes AppState and Channel definitions
+
+bool StateManager::initialize(AppState& app) {
+    if (isDataValid()) {
+        EepromData loadedState;
+        EEPROM.get(sizeof(Metadata), loadedState);
+        
+        // Restore main app state
+        app.selected_param = loadedState.selected_param;
+        app.selected_channel = loadedState.selected_channel;
+        app.selected_source = static_cast<Source>(loadedState.selected_source);
+        
+        // --- NEW: Loop through and restore each channel's state ---
+        for (int i = 0; i < OUTPUT_COUNT; i++) {
+            auto& ch = app.channel[i]; // Get a reference to the channel object
+            const auto& saved_ch_state = loadedState.channel_data[i]; // Get a const reference to the saved data
+
+            ch.setClockMod(saved_ch_state.base_clock_mod_index);
+            ch.setProbability(saved_ch_state.base_probability);
+            ch.setDutyCycle(saved_ch_state.base_duty_cycle);
+            ch.setOffset(saved_ch_state.base_offset);
+            ch.setCvSource(static_cast<CvSource>(saved_ch_state.cv_source));
+            ch.setCvDestination(static_cast<CvDestination>(saved_ch_state.cv_destination));
+        }
+        
+        return true;
+    } else {
+        writeMetadata();
+        save(app); // Save the initial default state
+        return false;
+    }
+}
+
+void StateManager::save(const AppState& app) {
+    EepromData stateToSave;
+    
+    // Populate main app state
+    stateToSave.selected_param = app.selected_param;
+    stateToSave.selected_channel = app.selected_channel;
+    stateToSave.selected_source = static_cast<byte>(app.selected_source);
+
+    // --- NEW: Loop through and populate each channel's state ---
+    for (int i = 0; i < OUTPUT_COUNT; i++) {
+        const auto& ch = app.channel[i]; // Get a const reference to the channel object
+        auto& saved_ch_state = stateToSave.channel_data[i]; // Get a reference to the struct we're saving to
+
+        // Use the getters with 'withCvMod = false' to get the base values
+        saved_ch_state.base_clock_mod_index = ch.getClockModIndex(false);
+        saved_ch_state.base_probability = ch.getProbability(false);
+        saved_ch_state.base_duty_cycle = ch.getDutyCycle(false);
+        saved_ch_state.base_offset = ch.getOffset(false);
+        saved_ch_state.cv_source = static_cast<byte>(ch.getCvSource());
+        saved_ch_state.cv_destination = static_cast<byte>(ch.getCvDestination());
+    }
+
+    // Write the entire state struct to EEPROM
+    EEPROM.put(sizeof(Metadata), stateToSave);
+}
+
+void StateManager::reset(AppState& app) {
+    AppState defaultState;
+    app = defaultState;
+    writeMetadata();
+    save(app);
+}
+
+// isDataValid() and writeMetadata() remain unchanged
+bool StateManager::isDataValid() {
+    Metadata storedMeta;
+    EEPROM.get(0, storedMeta);
+    bool nameMatch = (strcmp(storedMeta.sketchName, CURRENT_SKETCH_NAME) == 0);
+    bool versionMatch = (storedMeta.version == CURRENT_SKETCH_VERSION);
+    return nameMatch && versionMatch;
+}
+
+void StateManager::writeMetadata() {
+    Metadata currentMeta;
+    strcpy(currentMeta.sketchName, CURRENT_SKETCH_NAME);
+    currentMeta.version = CURRENT_SKETCH_VERSION;
+    EEPROM.put(0, currentMeta);
+}

examples/Gravity/save_state.h

@@ -0,0 +1,54 @@
+// File: save_state.h
+
+#ifndef SAVE_STATE_H
+#define SAVE_STATE_H
+
+#include <Arduino.h>
+#include <gravity.h> // We need this for OUTPUT_COUNT
+
+// Forward-declare AppState to avoid circular dependencies.
+struct AppState; 
+
+// Forward-declare the Source enum as well.
+enum Source;
+
+// Define the constants for the current firmware.
+const char CURRENT_SKETCH_NAME[] = "Gravity";
+const float CURRENT_SKETCH_VERSION = 0.2f; // You could increment this to 0.2 if you want to force a reset
+
+/**
+ * @brief Manages saving and loading of the application state to and from EEPROM.
+ */
+class StateManager {
+public:
+    bool initialize(AppState& app);
+    void save(const AppState& app);
+    void reset(AppState& app);
+
+private:
+    // This struct holds the data that identifies the firmware version.
+    struct Metadata {
+        char sketchName[16];
+        float version;
+    };
+    struct ChannelState {
+        byte base_clock_mod_index;
+        byte base_probability;
+        byte base_duty_cycle;
+        byte base_offset;
+        byte cv_source;      // We'll store the CvSource enum as a byte
+        byte cv_destination; // We'll store the CvDestination enum as a byte
+    };
+    // This struct holds all the parameters we want to save.
+    struct EepromData {
+        int selected_param;
+        byte selected_channel;
+        byte selected_source;
+        ChannelState channel_data[OUTPUT_COUNT]; 
+    };
+
+    bool isDataValid();
+    void writeMetadata();
+};
+
+#endif // SAVE_STATE_H