Merge branch 'fix/eink-button-irq-edge-capture'

examples/companion_radio/ui-new/UITask.cpp

@@ -1429,6 +1429,21 @@ void UITask::begin(DisplayDriver* display, SensorManager* sensors, NodePrefs* no
 #if defined(PIN_USER_BTN)
   user_btn.begin();
 #endif
+#if UI_HAS_JOYSTICK
+  // The directional joystick + Back share the same MomentaryButton machinery as
+  // user_btn but were never begin()'d — they only worked because the pins
+  // default to INPUT and the board has external pulls. That left them on the
+  // polling path: with BUTTON_USE_INTERRUPTS (e-ink) they'd silently never
+  // attach a GPIOTE channel, so edges landing during a blocking panel refresh
+  // were lost. begin() sets pinMode and claims an IRQ slot for each.
+  joystick_left.begin();
+  joystick_right.begin();
+  back_btn.begin();
+#if UI_HAS_JOYSTICK_UPDOWN
+  joystick_up.begin();
+  joystick_down.begin();
+#endif
+#endif
 #if defined(PIN_USER_BTN_ANA)
   analog_btn.begin();
 #endif
@@ -1970,8 +1985,22 @@ static void formatDashVal(uint8_t field, char* val, int val_len, uint16_t batt_m
   }
 }
 
+void UITask::enqueueKey(char c) {
+  if (c == 0) return;
+  uint8_t next = (_kq_head + 1) % KEY_QUEUE_SIZE;
+  if (next == _kq_tail) return;  // full: drop newest rather than clobber unprocessed keys
+  _key_queue[_kq_head] = c;
+  _kq_head = next;
+}
+
+bool UITask::dequeueKey(char& c) {
+  if (_kq_tail == _kq_head) return false;
+  c = _key_queue[_kq_tail];
+  _kq_tail = (_kq_tail + 1) % KEY_QUEUE_SIZE;
+  return true;
+}
+
 void UITask::loop() {
-  char c = 0;
   // Background delivery: resend pending on-device DMs whose ACK timed out, and
   // finalise the ✗ marker — runs regardless of which screen is active.
   ((QuickMsgScreen*)quick_msg)->tickDmResends();
@@ -2003,32 +2032,27 @@ void UITask::loop() {
       }
       // eat the Enter — don't pass to curr
     } else {
-      c = checkDisplayOn(KEY_ENTER);
+      enqueueKey(checkDisplayOn(KEY_ENTER));
     }
   } else if (ev == BUTTON_EVENT_LONG_PRESS) {
-    c = handleLongPress(KEY_ENTER);  // REVISIT: could be mapped to different key code
+    enqueueKey(handleLongPress(KEY_ENTER));  // REVISIT: could be mapped to different key code
   }
+  // Drain each direction fully: a burst of taps captured during a blocking
+  // refresh replays as several CLICKs, queued here and applied before one
+  // redraw (see enqueueKey / the dispatch at the end of loop()).
 #if UI_HAS_JOYSTICK_UPDOWN
-  ev = joystick_up.check();
+  while (joystick_up.check() == BUTTON_EVENT_CLICK)
-  if (ev == BUTTON_EVENT_CLICK) {
+    enqueueKey(checkDisplayOn(rotateJoystickKey(KEY_UP, joy_rot)));
-    c = checkDisplayOn(rotateJoystickKey(KEY_UP, joy_rot));
+  while (joystick_down.check() == BUTTON_EVENT_CLICK)
-  }
+    enqueueKey(checkDisplayOn(rotateJoystickKey(KEY_DOWN, joy_rot)));
-  ev = joystick_down.check();
-  if (ev == BUTTON_EVENT_CLICK) {
-    c = checkDisplayOn(rotateJoystickKey(KEY_DOWN, joy_rot));
-  }
 #endif
-  ev = joystick_left.check();
+  while ((ev = joystick_left.check()) != BUTTON_EVENT_NONE) {
-  if (ev == BUTTON_EVENT_CLICK) {
+    if (ev == BUTTON_EVENT_CLICK) enqueueKey(checkDisplayOn(rotateJoystickKey(KEY_LEFT, joy_rot)));
-    c = checkDisplayOn(rotateJoystickKey(KEY_LEFT, joy_rot));
+    else { if (ev == BUTTON_EVENT_LONG_PRESS) enqueueKey(handleLongPress(rotateJoystickKey(KEY_LEFT, joy_rot))); break; }
-  } else if (ev == BUTTON_EVENT_LONG_PRESS) {
-    c = handleLongPress(rotateJoystickKey(KEY_LEFT, joy_rot));
   }
-  ev = joystick_right.check();
+  while ((ev = joystick_right.check()) != BUTTON_EVENT_NONE) {
-  if (ev == BUTTON_EVENT_CLICK) {
+    if (ev == BUTTON_EVENT_CLICK) enqueueKey(checkDisplayOn(rotateJoystickKey(KEY_RIGHT, joy_rot)));
-    c = checkDisplayOn(rotateJoystickKey(KEY_RIGHT, joy_rot));
+    else { if (ev == BUTTON_EVENT_LONG_PRESS) enqueueKey(handleLongPress(rotateJoystickKey(KEY_RIGHT, joy_rot))); break; }
-  } else if (ev == BUTTON_EVENT_LONG_PRESS) {
-    c = handleLongPress(rotateJoystickKey(KEY_RIGHT, joy_rot));
   }
   if (_lock_seq_used && millis() - _lock_seq_ms > 5000) {
     _lock_seq_used = false;  // safety reset if Back release event was missed
@@ -2040,34 +2064,34 @@ void UITask::loop() {
       _lock_seq_count = 0;
       _lock_seq_used = false;
     } else {
-      c = checkDisplayOn(KEY_CANCEL);
+      enqueueKey(checkDisplayOn(KEY_CANCEL));
     }
   } else if (ev == BUTTON_EVENT_TRIPLE_CLICK) {
-    if (!_locked) c = handleTripleClick(KEY_SELECT);
+    if (!_locked) enqueueKey(handleTripleClick(KEY_SELECT));
   }
 #elif defined(PIN_USER_BTN)
   int ev = user_btn.check();
   if (ev == BUTTON_EVENT_CLICK) {
-    c = checkDisplayOn(KEY_NEXT);
+    enqueueKey(checkDisplayOn(KEY_NEXT));
   } else if (ev == BUTTON_EVENT_LONG_PRESS) {
-    c = handleLongPress(KEY_ENTER);
+    enqueueKey(handleLongPress(KEY_ENTER));
   } else if (ev == BUTTON_EVENT_DOUBLE_CLICK) {
-    c = handleDoubleClick(KEY_PREV);
+    enqueueKey(handleDoubleClick(KEY_PREV));
   } else if (ev == BUTTON_EVENT_TRIPLE_CLICK) {
-    c = handleTripleClick(KEY_SELECT);
+    enqueueKey(handleTripleClick(KEY_SELECT));
   }
 #endif
 #if defined(PIN_USER_BTN_ANA)
   if (millis() - _analogue_pin_read_millis > 10) {
     int ev = analog_btn.check();
     if (ev == BUTTON_EVENT_CLICK) {
-      c = checkDisplayOn(KEY_NEXT);
+      enqueueKey(checkDisplayOn(KEY_NEXT));
     } else if (ev == BUTTON_EVENT_LONG_PRESS) {
-      c = handleLongPress(KEY_ENTER);
+      enqueueKey(handleLongPress(KEY_ENTER));
     } else if (ev == BUTTON_EVENT_DOUBLE_CLICK) {
-      c = handleDoubleClick(KEY_PREV);
+      enqueueKey(handleDoubleClick(KEY_PREV));
     } else if (ev == BUTTON_EVENT_TRIPLE_CLICK) {
-      c = handleTripleClick(KEY_SELECT);
+      enqueueKey(handleTripleClick(KEY_SELECT));
     }
     _analogue_pin_read_millis = millis();
   }
@@ -2085,32 +2109,28 @@ void UITask::loop() {
 #endif
 
   // A ringing alarm/timer is dismissed by ANY key, even when locked or on another
-  // screen — and that key is swallowed so it doesn't also act on the current view.
+  // screen — and the queued keys are swallowed so they don't also act on the view.
-  if (c != 0 && isRinging()) {
+  if (_kq_head != _kq_tail && isRinging()) {
     dismissRing();
-    c = 0;
+    _kq_head = _kq_tail = 0;
     _next_refresh = 0;
   }
 
-  if (c != 0) {
+  if (_kq_head != _kq_tail) {
     if (!_locked && curr) {
-      curr->handleInput(c);
+      // Apply the whole queued burst, then redraw once — N taps captured during
+      // a blocking refresh become N navigation steps at the cost of one refresh.
+      char k;
+      while (dequeueKey(k)) curr->handleInput(k);
       { uint32_t aoff = autoOffMillis(); if (aoff > 0) _auto_off = millis() + aoff; }  // extend auto-off timer
-#ifdef PIN_BUZZER
+      // Note timing no longer depends on render cadence (TIMER1 IRQ advances
-      if (buzzer.isPlaying()) {
+      // notes directly — see buzzer.cpp), so a redraw right after a keypress
-        // Keep the next render at least 300 ms away so the blocking e-ink endFrame()
+      // can't clip a note; no need to hold it back while buzzer.isPlaying().
-        // doesn't extend the current note.  300 ms covers the slowest note at 120 BPM (1/4).
+      _next_refresh = 100;  // trigger refresh immediately
-        unsigned long deadline = millis() + 300;
+    } else {
-        if (_next_refresh < deadline) _next_refresh = deadline;
+      _kq_head = _kq_tail = 0;  // locked or no screen: eat all queued keys
-      } else {
+      // Locked: wake window is set only when display first turns on
-        _next_refresh = 100;  // trigger refresh immediately
+      if (_locked) _next_refresh = 0;
-      }
-#else
-      _next_refresh = 100;  // trigger refresh
-#endif
-    } else if (_locked) {
-      // Locked: eat all keys — wake window is set only when display first turns on
-      _next_refresh = 0;
     }
   }
 

examples/companion_radio/ui-new/UITask.h

@@ -174,6 +174,17 @@ class UITask : public AbstractUITask {
   char handleDoubleClick(char c);
   char handleTripleClick(char c);
 
+  // Key FIFO: a burst of taps captured during a blocking refresh (e-ink) is
+  // drained from the buttons into this queue, then all keys are applied before
+  // a single redraw — so rapid navigation steps neither get lost nor cost one
+  // slow refresh each. Also fixes losing a key when two buttons fire in the
+  // same loop iteration.
+  static const uint8_t KEY_QUEUE_SIZE = 16;
+  char _key_queue[KEY_QUEUE_SIZE];
+  uint8_t _kq_head = 0, _kq_tail = 0;
+  void enqueueKey(char c);
+  bool dequeueKey(char& c);
+
   void setCurrScreen(UIScreen* c);
 
 public:

src/helpers/ui/MomentaryButton.cpp

@@ -2,6 +2,57 @@
 
 #define MULTI_CLICK_WINDOW_MS  280
 
+#ifdef BUTTON_USE_INTERRUPTS
+#define ISR_DEBOUNCE_MS  5
+
+MomentaryButton* MomentaryButton::_isr_table[MomentaryButton::MAX_ISR_BUTTONS] = { nullptr };
+
+#define DEFINE_ISR_TRAMPOLINE(n) \
+  void MomentaryButton::isrTrampoline##n() { if (_isr_table[n]) _isr_table[n]->isrHandler(); }
+DEFINE_ISR_TRAMPOLINE(0)
+DEFINE_ISR_TRAMPOLINE(1)
+DEFINE_ISR_TRAMPOLINE(2)
+DEFINE_ISR_TRAMPOLINE(3)
+DEFINE_ISR_TRAMPOLINE(4)
+DEFINE_ISR_TRAMPOLINE(5)
+DEFINE_ISR_TRAMPOLINE(6)
+DEFINE_ISR_TRAMPOLINE(7)
+#undef DEFINE_ISR_TRAMPOLINE
+
+// attachInterrupt() takes a plain void(*)() with no user-data slot on the
+// Adafruit nRF52 and ESP32 Arduino cores, so each button needs its own
+// trampoline to know which instance to dispatch to.
+static void (*const ISR_TRAMPOLINES[MomentaryButton::MAX_ISR_BUTTONS])() = {
+  MomentaryButton::isrTrampoline0, MomentaryButton::isrTrampoline1,
+  MomentaryButton::isrTrampoline2, MomentaryButton::isrTrampoline3,
+  MomentaryButton::isrTrampoline4, MomentaryButton::isrTrampoline5,
+  MomentaryButton::isrTrampoline6, MomentaryButton::isrTrampoline7,
+};
+
+void MomentaryButton::pushEdge(uint8_t level, uint32_t at) {
+  uint8_t next = (_edge_head + 1) % EDGE_BUF_SIZE;
+  if (next == _edge_tail) return;  // full: drop rather than clobber older, unprocessed edges
+  _edge_level[_edge_head] = level;
+  _edge_time[_edge_head] = at;
+  _edge_head = next;
+}
+
+bool MomentaryButton::popEdge(uint8_t &level, uint32_t &at) {
+  if (_edge_tail == _edge_head) return false;
+  level = _edge_level[_edge_tail];
+  at = _edge_time[_edge_tail];
+  _edge_tail = (_edge_tail + 1) % EDGE_BUF_SIZE;
+  return true;
+}
+
+void MomentaryButton::isrHandler() {
+  uint32_t now = millis();
+  if (now - _last_isr_edge < ISR_DEBOUNCE_MS) return;  // mechanical contact-bounce guard
+  _last_isr_edge = now;
+  pushEdge(digitalRead(_pin), now);
+}
+#endif
+
 MomentaryButton::MomentaryButton(int8_t pin, int long_press_millis, bool reverse, bool pulldownup, bool multiclick) { 
   _pin = pin;
   _reverse = reverse;
@@ -35,6 +86,24 @@ MomentaryButton::MomentaryButton(int8_t pin, int long_press_millis, int analog_t
 void MomentaryButton::begin() {
   if (_pin >= 0 && _threshold == 0) {
     pinMode(_pin, _pull ? (_reverse ? INPUT_PULLUP : INPUT_PULLDOWN) : INPUT);
+#ifdef BUTTON_USE_INTERRUPTS
+    for (uint8_t i = 0; i < MAX_ISR_BUTTONS; i++) {
+      if (_isr_table[i] == nullptr) {
+        // The nRF52 has only 8 GPIOTE channels, shared across every pin using
+        // attachInterrupt() (the radio's DIO1 takes one too). It returns 0 when
+        // they're exhausted — only claim the trampoline slot if a channel was
+        // actually allocated. Otherwise leave _isr_slot = -1 so check() uses the
+        // polling path: that button still works, it just won't capture edges
+        // that land during a blocking display refresh. Retrying another index is
+        // pointless — the channel pool, not the trampoline slot, is what ran out.
+        if (attachInterrupt(digitalPinToInterrupt(_pin), ISR_TRAMPOLINES[i], CHANGE) != 0) {
+          _isr_table[i] = this;
+          _isr_slot = i;
+        }
+        break;
+      }
+    }
+#endif
   }
 }
 
@@ -62,36 +131,53 @@ bool MomentaryButton::isPressed(int level) const {
   }
 }
 
+void MomentaryButton::applyTransition(int btn, unsigned long at) {
+  if (btn == prev) return;
+  if (isPressed(btn)) {
+    down_at = at;
+  } else {
+    // button UP
+    if (_long_millis > 0) {
+      if (down_at > 0 && (unsigned long)(at - down_at) < (unsigned long)_long_millis) {  // only a CLICK if still within the long_press millis
+          _click_count++;
+          _last_click_time = at;
+          _pending_click = true;
+      }
+    } else {
+        _click_count++;
+        _last_click_time = at;
+        _pending_click = true;
+    }
+    down_at = 0;
+  }
+  prev = btn;
+}
+
 int MomentaryButton::check(bool repeat_click) {
   if (_pin < 0) return BUTTON_EVENT_NONE;
 
   int event = BUTTON_EVENT_NONE;
-  int btn = _threshold > 0 ? (analogRead(_pin) < _threshold) : digitalRead(_pin);
+  int btn;
-  if (btn != prev) {
+#ifdef BUTTON_USE_INTERRUPTS
-    if (isPressed(btn)) {
+  if (_isr_slot >= 0) {
-      down_at = millis();
+    // Replay edges the ISR caught while the main loop was off doing something
-    } else {
+    // blocking (e-ink refresh) — each keeps its own capture timestamp so
-      // button UP
+    // click-duration / multi-click-window math still lines up correctly.
-      if (_long_millis > 0) {
+    uint8_t lvl; uint32_t at;
-        if (down_at > 0 && (unsigned long)(millis() - down_at) < _long_millis) {  // only a CLICK if still within the long_press millis
+    while (popEdge(lvl, at)) applyTransition(lvl, at);
-            _click_count++;
+    // Self-heal: if an edge was ever lost (buffer overflow, a debounce-dropped
-            _last_click_time = millis();
+    // settling edge, or a missed GPIOTE event), prev would otherwise stay
-            _pending_click = true;
+    // diverged from the hardware until the next captured edge — a stuck button.
-        }
+    // Reconcile against the live pin; a no-op whenever the edge stream already
-      } else {
+    // matches it, which is the normal case.
-          _click_count++;
+    int live = digitalRead(_pin);
-          _last_click_time = millis();
+    if (live != prev) applyTransition(live, millis());
-          _pending_click = true;
+    btn = prev;
-      }
+  } else
-      if (event == BUTTON_EVENT_CLICK && cancel) {
+#endif
-        event = BUTTON_EVENT_NONE;
+  {
-        _click_count = 0;
+    btn = _threshold > 0 ? (analogRead(_pin) < _threshold) : digitalRead(_pin);
-        _last_click_time = 0;
+    applyTransition(btn, millis());
-        _pending_click = false;
-      }
-      down_at = 0;
-    }
-    prev = btn;
   }
   if (!isPressed(btn) && cancel) {   // always clear the pending 'cancel' once button is back in UP state
     cancel = 0;
@@ -116,7 +202,22 @@ int MomentaryButton::check(bool repeat_click) {
     }
   }
 
-  if (_pending_click && (millis() - _last_click_time) >= _multi_click_window) {
+  if (_multi_click_window == 0) {
+    // No multi-click semantics: every completed press is an independent CLICK.
+    // When a burst of taps is captured during a blocking refresh (e-ink), all
+    // their edges replay into _click_count in a single check(); emit them one
+    // CLICK per call (decrementing) instead of collapsing into a lone
+    // double/triple event the caller would ignore — so each tap survives as a
+    // discrete key. Waits for release (down_at == 0) so a held button doesn't
+    // fire mid-press.
+    if (_pending_click && down_at == 0) {
+      event = BUTTON_EVENT_CLICK;
+      if (--_click_count == 0) {
+        _last_click_time = 0;
+        _pending_click = false;
+      }
+    }
+  } else if (_pending_click && (millis() - _last_click_time) >= _multi_click_window) {
     if (down_at > 0) {
       // still pressed - wait for button release before processing clicks
       return event;

src/helpers/ui/MomentaryButton.h

@@ -21,6 +21,41 @@ class MomentaryButton {
   bool _pending_click;
 
   bool isPressed(int level) const;
+  void applyTransition(int btn, unsigned long at);
+
+#ifdef BUTTON_USE_INTERRUPTS
+  // GPIO-IRQ edge capture: boards whose display blocks the main loop for a
+  // long time per refresh (e-ink) can miss an entire press+release cycle if
+  // check() only ever samples the live pin. The ISR latches edges with their
+  // own timestamp into a small ring buffer; check() replays them so no tap
+  // gets lost while the loop is stuck waiting on the panel.
+  int8_t _isr_slot = -1;
+  static const uint8_t EDGE_BUF_SIZE = 16;
+  volatile uint8_t _edge_level[EDGE_BUF_SIZE];
+  volatile uint32_t _edge_time[EDGE_BUF_SIZE];
+  volatile uint8_t _edge_head = 0, _edge_tail = 0;
+  volatile uint32_t _last_isr_edge = 0;
+
+  void pushEdge(uint8_t level, uint32_t at);
+  bool popEdge(uint8_t &level, uint32_t &at);
+  void isrHandler();
+  static MomentaryButton* _isr_table[8];
+
+public:
+  // MAX_ISR_BUTTONS/isrTrampolineN must be public: attachInterrupt() needs a
+  // plain free-function pointer, taken from a file-scope table outside the
+  // class (see MomentaryButton.cpp), which needs both to size and fill itself.
+  static const uint8_t MAX_ISR_BUTTONS = 8;
+  static void isrTrampoline0();
+  static void isrTrampoline1();
+  static void isrTrampoline2();
+  static void isrTrampoline3();
+  static void isrTrampoline4();
+  static void isrTrampoline5();
+  static void isrTrampoline6();
+  static void isrTrampoline7();
+private:
+#endif
 
 public:
   MomentaryButton(int8_t pin, int long_press_mills=0, bool reverse=false, bool pulldownup=false, bool multiclick=true);

src/helpers/ui/buzzer.cpp

@@ -9,6 +9,20 @@ void genericBuzzer::begin() {
     #endif
     pinMode(PIN_BUZZER, OUTPUT);
     digitalWrite(PIN_BUZZER, LOW); // need to pull low by default to avoid extreme power draw
+#if defined(NRF52_PLATFORM)
+    _isr_instance = this;
+    NRF_TIMER1->TASKS_STOP  = 1;
+    NRF_TIMER1->MODE        = TIMER_MODE_MODE_Timer << TIMER_MODE_MODE_Pos;
+    NRF_TIMER1->BITMODE     = TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos;
+    NRF_TIMER1->PRESCALER   = 4;   // 16 MHz / 2^4 = 1 MHz -> 1 us/tick
+    NRF_TIMER1->SHORTS      = TIMER_SHORTS_COMPARE0_CLEAR_Msk | TIMER_SHORTS_COMPARE0_STOP_Msk;
+    NRF_TIMER1->INTENSET    = TIMER_INTENSET_COMPARE0_Msk;
+    // Lowest application priority: this only ever reschedules a tone, it must
+    // never contend with anything radio/BLE-timing-critical.
+    NVIC_SetPriority(TIMER1_IRQn, 7);
+    NVIC_ClearPendingIRQ(TIMER1_IRQn);
+    NVIC_EnableIRQ(TIMER1_IRQn);
+#endif
     startup();
 }
 
@@ -150,7 +164,41 @@ void genericBuzzer::_nrfStopPwm() {
     _pwm_on = false;
 }
 
+genericBuzzer* genericBuzzer::_isr_instance = nullptr;
+
+void genericBuzzer::_armNoteTimer(uint32_t dur_ms) {
+    NRF_TIMER1->TASKS_STOP  = 1;
+    NRF_TIMER1->TASKS_CLEAR = 1;
+    NRF_TIMER1->EVENTS_COMPARE[0] = 0;
+    NRF_TIMER1->CC[0] = dur_ms * 1000UL;   // 1 us/tick (see PRESCALER in begin())
+    NRF_TIMER1->TASKS_START = 1;
+}
+
+// Halt the timer AND drop any interrupt it already latched. Stopping the timer
+// and clearing EVENTS_COMPARE[0] de-asserts the IRQ source, but an interrupt
+// the NVIC latched just before we stopped stays pending and would fire one
+// spurious _nrfAdvance() after we return — skipping the first note of a new
+// melody, or sounding a blip just after an explicit stop. Order matters: clear
+// the event (with a read-back to flush the write buffer, per the nRF52 event
+// anomaly) before clearing the NVIC, else the still-set event re-latches it.
+void genericBuzzer::_disarmNoteTimer() {
+    NRF_TIMER1->TASKS_STOP = 1;
+    NRF_TIMER1->EVENTS_COMPARE[0] = 0;
+    (void)NRF_TIMER1->EVENTS_COMPARE[0];
+    NVIC_ClearPendingIRQ(TIMER1_IRQn);
+}
+
+// Static member (not a free function) so it can reach private state without a
+// friend declaration — same trick MomentaryButton's isrTrampolineN() uses.
+// The real ISR (TIMER1_IRQHandler, below) is just a one-line dispatch to this.
+void genericBuzzer::_timer1ISR() {
+    NRF_TIMER1->EVENTS_COMPARE[0] = 0;
+    (void)NRF_TIMER1->EVENTS_COMPARE[0];   // flush write buffer so the IRQ doesn't immediately re-fire (nRF52 anomaly)
+    if (_isr_instance) _isr_instance->_nrfAdvance();
+}
+
 void genericBuzzer::_nrfBegin(const char* melody) {
+    _disarmNoteTimer();   // drop any in-flight/pending note advance before reconfiguring
     _nrfStopPwm();
     if (!melody || !*melody) { _rtttl_done = true; return; }
     const char* notes;
@@ -163,7 +211,7 @@ void genericBuzzer::_nrfBegin(const char* melody) {
 void genericBuzzer::_nrfAdvance() {
     uint16_t freq; uint32_t dur_ms;
     if (_parseNext(_rtttl_pos, _def_dur, _def_oct, _def_bpm, freq, dur_ms)) {
-        _note_end_ms = millis() + dur_ms;
+        _armNoteTimer(dur_ms);
         if (freq > 0) _nrfStartPwm(freq); else _nrfStopPwm();
     } else {
         _nrfStopPwm();
@@ -191,12 +239,20 @@ void genericBuzzer::playForced(const char* melody) {
 bool genericBuzzer::isPlaying() { return !_rtttl_done; }
 
 void genericBuzzer::stop() {
+    _disarmNoteTimer();   // ensure no latched note-advance fires after we stop
     _nrfStopPwm();
     _rtttl_done = true;
 }
 
-void genericBuzzer::loop() {
+// No-op: TIMER1's compare interrupt (_timer1ISR -> _nrfAdvance) now drives
-    if (!_rtttl_done && (millis() >= _note_end_ms)) _nrfAdvance();
+// note advancement directly, so timing no longer depends on how often (or
+// whether) the caller's loop() gets to run. Kept as a real method, not
+// removed, since UITask polls buzzer.loop() unconditionally for both
+// platforms.
+void genericBuzzer::loop() {}
+
+extern "C" void TIMER1_IRQHandler(void) {
+    genericBuzzer::_timer1ISR();
 }
 
 void genericBuzzer::setVolume(uint8_t level) {

src/helpers/ui/buzzer.h

@@ -54,7 +54,6 @@ class genericBuzzer
         const char*   _rtttl_pos   = nullptr;
         bool          _rtttl_done  = true;
         bool          _pwm_on      = false;
-        unsigned long _note_end_ms = 0;
         uint8_t       _def_dur     = 4;
         uint8_t       _def_oct     = 5;
         uint16_t      _def_bpm     = 120;
@@ -69,5 +68,21 @@ class genericBuzzer
                                    uint16_t bpm, uint16_t& freq_hz, uint32_t& dur_ms);
         static void     _parseHeader(const char* melody, uint8_t& def_dur, uint8_t& def_oct,
                                      uint16_t& bpm, const char*& notes_start);
+
+        // TIMER1-driven note advance: a hardware compare interrupt calls
+        // _nrfAdvance() at the exact moment the current note's duration ends,
+        // so playback timing survives a blocking display refresh (e-ink)
+        // instead of waiting for the next loop() poll. Same reasoning as
+        // MomentaryButton's GPIO-IRQ edge capture, just timer- rather than
+        // pin-driven. TIMER0 is reserved by the SoftDevice; TIMER1 is free.
+        void _armNoteTimer(uint32_t dur_ms);
+        void _disarmNoteTimer();
+        static genericBuzzer* _isr_instance;
+
+    public:
+        // Must be public: the extern "C" TIMER1_IRQHandler (see buzzer.cpp) is
+        // a free function — the vector table requires that exact symbol — so
+        // it needs access from outside the class to dispatch into it.
+        static void _timer1ISR();
 #endif
 };

variants/wio-tracker-l1-eink/platformio.ini

@@ -29,6 +29,7 @@ build_flags = ${nrf52_base.build_flags}
   -D MAX_GROUP_CHANNELS=40
   -D OFFLINE_QUEUE_SIZE=256
   -D DISPLAY_CLASS=GxEPDDisplay
+  -D BUTTON_USE_INTERRUPTS=1
   -D UI_HAS_JOYSTICK=1
   -D UI_HAS_JOYSTICK_UPDOWN=1
   -D PIN_BUZZER=12