examples/Gravity/Gravity.ino

@@ -213,6 +213,12 @@ void editChannelParameter(int val) {
         case PARAM_CH_SWING:
             ch.setSwing(ch.getSwing() + val);
             break;
+        case PARAM_CH_EUC_STEPS:
+            ch.setSteps(ch.getSteps() + val);
+            break;
+        case PARAM_CH_EUC_HITS:
+            ch.setHits(ch.getHits() + val);
+            break;
         case PARAM_CH_CV_SRC: {
             int source = static_cast<int>(ch.getCvSource());
             updateSelection(source, val, CV_LAST);

examples/Gravity/app_state.h

@@ -39,6 +39,8 @@ enum ParamsChannelPage {
     PARAM_CH_DUTY,
     PARAM_CH_OFFSET,
     PARAM_CH_SWING,
+    PARAM_CH_EUC_STEPS,
+    PARAM_CH_EUC_HITS,
     PARAM_CH_CV_SRC,
     PARAM_CH_CV_DEST,
     PARAM_CH_LAST,

examples/Gravity/channel.h

@@ -3,6 +3,7 @@
 
 #include <Arduino.h>
 #include <gravity.h>
+#include "euclidean.h"
 
 // Enums for CV configuration
 enum CvSource {
@@ -41,6 +42,7 @@ class Channel {
         base_duty_cycle = 50;
         base_offset = 0;
         base_swing = 50;
+
         cv_source = CV_NONE;
         cv_destination = CV_DEST_NONE;
 
@@ -49,6 +51,8 @@ class Channel {
         cvmod_duty_cycle = base_duty_cycle;
         cvmod_offset = base_offset;
         cvmod_swing = base_swing;
+
+        pattern.Init(DEFAULT_PATTERN);
     }
 
     // Setters (Set the BASE value)
@@ -75,6 +79,13 @@ class Channel {
     CvDestination getCvDestination() { return cv_destination; }
     bool isCvModActive() const { return cv_source != CV_NONE && cv_destination != CV_DEST_NONE; }
 
+    // Euclidean
+    void setSteps(byte val) { pattern.SetSteps(val); }
+    void setHits(byte val) { pattern.SetHits(val); }
+
+    byte getSteps() { pattern.GetSteps(); }
+    byte getHits() { pattern.GetHits(); }
+
     /**
      * @brief Processes a clock tick and determines if the output should be high or low.
      * @param tick The current clock tick count.
@@ -95,11 +106,26 @@ class Channel {
 
         const uint32_t current_tick_offset = tick + offset_pulses + swing_pulses;
 
-        // Step check
+        // Duty cycle high check logic
         if (!output.On()) {
+            // Step check
             if (current_tick_offset % mod_pulses == 0) {
-                // Duty cycle high check
+                bool hit = cvmod_probability >= random(0, 100);
-                if (cvmod_probability >= random(0, 100)) {
+                if (pattern.IsActive()) {
+                    // Euclidean rhythm check
+                    switch (pattern.NextStep()) {
+                    case Pattern::REST:  // Rest when active or fall back to probability
+                        hit = pattern.IsActive() ? false : hit;
+                        break;
+                    case Pattern::HIT:  // Hit if probability is true
+                        hit &= true;
+                        break;
+                    case Pattern::PADDING:  // Padding returns only when active, always rest)
+                        hit = false;
+                        break;
+                    }
+                }
+                if (hit) {
                     output.High();
                 }
             }
@@ -173,6 +199,9 @@ class Channel {
     // CV configuration
     CvSource cv_source = CV_NONE;
     CvDestination cv_destination = CV_DEST_NONE;
+
+    // Euclidean pattern
+    Pattern pattern;
 };
 
 #endif  // CHANNEL_H

examples/Gravity/display.h

@@ -269,6 +269,14 @@ void DisplayChannelPage() {
             subText = "DOWN BEAT";
             swingDivisionMark();
             break;
+        case PARAM_CH_EUC_STEPS:
+            mainText = String(ch.getSteps());
+            subText = "EUCLID STEPS";
+            break;
+        case PARAM_CH_EUC_HITS:
+            mainText = String(ch.getHits());
+            subText = "EUCLID HITS";
+            break;
         case PARAM_CH_CV_SRC: {
             switch (ch.getCvSource()) {
                 mainText = F("SRC");
@@ -315,7 +323,8 @@ void DisplayChannelPage() {
 
     // Draw Channel Page menu items
     String menu_items[PARAM_CH_LAST] = {
-        F("MOD"), F("PROBABILITY"), F("DUTY"), F("OFFSET"), F("SWING"), F("CV SOURCE"), F("CV DEST")};
+        F("MOD"), F("PROBABILITY"), F("DUTY"), F("OFFSET"), F("SWING"), F("EUC STEPS"), 
+        F("EUC HITS"), F("CV SOURCE"), F("CV DEST")};
     drawMenuItems(menu_items, PARAM_CH_LAST);
 }
 

examples/Gravity/euclidean.h

@@ -0,0 +1,111 @@
+#ifndef EUCLIDEAN_H
+#define EUCLIDEAN_H
+
+#define MAX_PATTERN_LEN 16
+
+struct PatternState {
+    uint8_t steps;
+    uint8_t hits;
+};
+
+const PatternState DEFAULT_PATTERN = {16, 4};
+
+class Pattern {
+   public:
+    Pattern() {}
+    ~Pattern() {}
+
+    enum Step {
+        HIT,
+        REST,
+        PADDING,
+    };
+
+    void Init(PatternState state) {
+        steps_ = constrain(state.steps, 0, MAX_PATTERN_LEN);
+        hits_ = constrain(state.hits, 1, steps_);
+        updatePattern();
+    }
+
+    PatternState GetState() { return {steps_, hits_}; }
+
+    // Get the current step value and advance the euclidean rhythm step index
+    // to the next step in the pattern.
+    Step NextStep() {
+        byte padding_ = 0;
+        if (steps_ == 0) return REST;
+
+        Step value = GetCurrentStep(current_step_);
+        current_step_ =
+            (current_step_ < steps_ + padding_ - 1) ? current_step_ + 1 : 0;
+        return value;
+    }
+
+    Step GetCurrentStep(byte i) { return pattern_[i]; }
+
+    void SetSteps(byte steps) {
+        steps_ = constrain(steps, 0, MAX_PATTERN_LEN);
+        hits_ = min(hits_, steps_);
+        updatePattern();
+    }
+
+    void SetHits(byte hits) {
+        hits_ = constrain(hits, 0, steps_);
+    }
+
+    // void ChangeOffset(byte val) {
+    //     offset_ = constrain(offset_ + val, 0, (steps_ + padding_));
+    //     updatePattern();
+    // }
+
+    // void ChangePadding(byte val) {
+    //     if (val == 1 && padding_ + steps_ < MAX_PATTERN_LEN) {
+    //         padding_++;
+    //         updatePattern();
+    //     } else if (val == -1 && padding_ > 0) {
+    //         padding_--;
+    //         offset_ = min(offset_, (padding_ + steps_) - 1);
+    //         updatePattern();
+    //     }
+    // }
+
+    void Reset() { current_step_ = 0; }
+    bool IsActive() { return steps_ != 0 && hits_ != 0; }
+
+    inline uint8_t GetSteps() { return steps_; }
+    inline uint8_t GetHits() { return hits_; }
+    inline uint8_t GetStepIndex() { return current_step_; }
+
+   private:
+    uint8_t steps_ = 0;
+    uint8_t hits_ = 0;
+    volatile uint8_t current_step_ = 0;
+    Step pattern_[MAX_PATTERN_LEN];
+
+    // Update the euclidean rhythm pattern when attributes change.
+    void updatePattern() {
+        // Fill current pattern with "padding" steps, then overwrite with hits
+        // and rests.
+        for (int i = 0; i < MAX_PATTERN_LEN; i++) {
+            pattern_[i] = PADDING;
+        }
+
+        // Populate the euclidean rhythm pattern according to the current
+        // instance variables.
+        byte bucket = 0;
+        byte offset_ = 0;  // temp disable
+        byte padding_ = 0;  // temp disable
+        pattern_[offset_] = (hits_ > 0) ? HIT : REST;
+        for (int i = 1; i < steps_; i++) {
+            bucket += hits_;
+            if (bucket >= steps_) {
+                bucket -= steps_;
+                pattern_[(i + offset_) % (steps_ + padding_)] = HIT;
+            } else {
+                pattern_[(i + offset_) % (steps_ + padding_)] = REST;
+            }
+        }
+    }
+};
+
+#endif

examples/Gravity/save_state.h

@@ -9,7 +9,7 @@ struct AppState;
 
 // Define the constants for the current firmware.
 const char SKETCH_NAME[] = "Gravity";
-const byte SKETCH_VERSION = 4;
+const byte SKETCH_VERSION = 5;
 
 // Define the minimum amount of time between EEPROM writes.
 static const unsigned long SAVE_DELAY_MS = 2000;