nice dithering

Firmware/main/CMakeLists.txt

@@ -17,7 +17,7 @@ idf_component_register(SRCS
         src/buzzer.cpp
         src/fs_helper.cpp
         PRIV_REQUIRES spi_flash esp_driver_i2c driver sdk-esp esp_timer nvs_flash littlefs
-        INCLUDE_DIRS "include" "Peanut-GB"
+        INCLUDE_DIRS "include"
         EMBED_FILES "roms/builtin_demo1.gb" "roms/builtin_demo2.gb")
 
 littlefs_create_partition_image(littlefs ../flash_data FLASH_IN_PROJECT)

Firmware/main/include/app_framework.hpp

@@ -11,6 +11,30 @@
 
 class AppSystem;
 
+using AppTimerHandle = std::uint32_t;
+constexpr AppTimerHandle kInvalidAppTimer = 0;
+
+enum class AppEventType {
+    Button,
+    Timer,
+};
+
+struct AppButtonEvent {
+    InputState current{};
+    InputState previous{};
+};
+
+struct AppTimerEvent {
+    AppTimerHandle handle = kInvalidAppTimer;
+};
+
+struct AppEvent {
+    AppEventType   type;
+    std::uint32_t  timestamp_ms = 0;
+    AppButtonEvent button{};
+    AppTimerEvent  timer{};
+};
+
 template<typename FramebufferT, typename InputT, typename ClockT>
 struct BasicAppContext {
     using Framebuffer = FramebufferT;
@@ -40,28 +64,50 @@ struct BasicAppContext {
 
     bool hasPendingAppSwitch() const { return pendingSwitch; }
 
+    AppTimerHandle scheduleTimer(uint32_t delay_ms, bool repeat = false) {
+        if (!system)
+            return kInvalidAppTimer;
+        return scheduleTimerInternal(delay_ms, repeat);
+    }
+
+    AppTimerHandle scheduleRepeatingTimer(uint32_t interval_ms) {
+        if (!system)
+            return kInvalidAppTimer;
+        return scheduleTimerInternal(interval_ms, true);
+    }
+
+    void cancelTimer(AppTimerHandle handle) {
+        if (!system)
+            return;
+        cancelTimerInternal(handle);
+    }
+
+    void cancelAllTimers() {
+        if (!system)
+            return;
+        cancelAllTimersInternal();
+    }
+
 private:
     friend class AppSystem;
     bool        pendingSwitch       = false;
     bool        pendingSwitchByName = false;
     std::size_t pendingAppIndex     = 0;
     std::string pendingAppName;
+
+    AppTimerHandle scheduleTimerInternal(uint32_t delay_ms, bool repeat);
+    void           cancelTimerInternal(AppTimerHandle handle);
+    void           cancelAllTimersInternal();
 };
 
 using AppContext = BasicAppContext<PlatformFramebuffer, PlatformInput, PlatformClock>;
 
-struct AppSleepPlan {
-    uint32_t slow_ms   = 0; // long sleep allowing battery/UI periodic refresh
-    uint32_t normal_ms = 0; // short sleep for responsiveness on input wake
-};
-
 class IApp {
 public:
     virtual ~IApp() = default;
-    virtual void         onStart() {}
-    virtual void         onStop() {}
-    virtual void         step() = 0;
-    virtual AppSleepPlan sleepPlan(uint32_t now) const { return {}; }
+    virtual void onStart() {}
+    virtual void onStop() {}
+    virtual void handleEvent(const AppEvent& event) = 0;
 };
 
 class IAppFactory {

Firmware/main/include/app_system.hpp

@@ -2,6 +2,7 @@
 
 #include "app_framework.hpp"
 
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <vector>
@@ -25,9 +26,54 @@ public:
     [[nodiscard]] const IAppFactory* currentFactory() const { return activeFactory; }
 
 private:
+    template<typename FramebufferT, typename InputT, typename ClockT>
+    friend struct BasicAppContext;
+
+    struct TimerRecord {
+        AppTimerHandle id          = kInvalidAppTimer;
+        std::uint32_t  generation  = 0;
+        std::uint32_t  due_ms      = 0;
+        std::uint32_t  interval_ms = 0;
+        bool           repeat      = false;
+        bool           active      = false;
+    };
+
+    AppTimerHandle scheduleTimer(uint32_t delay_ms, bool repeat);
+    void           cancelTimer(AppTimerHandle handle);
+    void           cancelAllTimers();
+
+    void dispatchEvent(const AppEvent& event);
+
+    void processDueTimers(std::uint32_t now, std::vector<AppEvent>& outEvents);
+    std::uint32_t nextTimerDueMs(std::uint32_t now) const;
+    void          clearTimersForCurrentApp();
+    TimerRecord*  findTimer(AppTimerHandle handle);
+    bool          handlePendingSwitchRequest();
+
     AppContext                       context;
     std::vector<std::unique_ptr<IAppFactory>> factories;
     std::unique_ptr<IApp>                    current;
     IAppFactory*                             activeFactory = nullptr;
     std::size_t                               activeIndex   = static_cast<std::size_t>(-1);
+    std::vector<TimerRecord>                 timers;
+    AppTimerHandle                           nextTimerId      = 1;
+    std::uint32_t                            currentGeneration = 0;
+    InputState                               lastInputState{};
 };
+
+template<typename FramebufferT, typename InputT, typename ClockT>
+AppTimerHandle BasicAppContext<FramebufferT, InputT, ClockT>::scheduleTimerInternal(uint32_t delay_ms, bool repeat) {
+    return system ? system->scheduleTimer(delay_ms, repeat) : kInvalidAppTimer;
+}
+
+template<typename FramebufferT, typename InputT, typename ClockT>
+void BasicAppContext<FramebufferT, InputT, ClockT>::cancelTimerInternal(AppTimerHandle handle) {
+    if (system)
+        system->cancelTimer(handle);
+}
+
+template<typename FramebufferT, typename InputT, typename ClockT>
+void BasicAppContext<FramebufferT, InputT, ClockT>::cancelAllTimersInternal() {
+    if (system)
+        system->cancelAllTimers();
+}

Firmware/main/include/buttons.hpp

@@ -25,6 +25,7 @@ public:
     void            pooler(); // FIXME:
     uint8_t         get_pressed();
     void install_isr();
+    void register_listener(TaskHandle_t task);
 
     TaskHandle_t     _pooler_task;
 
@@ -32,6 +33,7 @@ private:
     Buttons();
 
     volatile uint8_t _current;
+    volatile TaskHandle_t _listener = nullptr;
 };
 
 

Firmware/main/include/display.hpp

@@ -21,15 +21,15 @@ static constexpr size_t kLineBytes       = DISP_WIDTH / 8;
 static constexpr size_t kLineMultiSingle = (kLineBytes + 2);
 static constexpr size_t kLineDataBytes   = kLineMultiSingle * DISP_HEIGHT + 2;
 
-extern uint8_t dma_buf[SMD::kLineDataBytes];
+extern uint8_t* dma_buf;
 
 void init();
-// Simplified asynchronous frame pipeline:
+// Double-buffered asynchronous frame pipeline:
 // Usage pattern each frame:
-//   SMD::async_draw_wait();  // (start of frame) waits for previous transfer+clear & guarantees pixel area is zeroed
+//   SMD::async_draw_wait();  // (start of frame) waits for previous transfer & ensures draw buffer is ready/synced
 //   ... write pixels into dma_buf via set_pixel / surface ...
-//   SMD::async_draw_start(); // (end of frame) queues SPI DMA of current framebuffer; when DMA completes it triggers
-//                            // a background clear of pixel bytes for next frame
+//   SMD::async_draw_start(); // (end of frame) queues SPI DMA of current framebuffer; once SPI finishes the sent buffer
+//                           // is asynchronously cleared so the alternate buffer is ready for the next frame
 void async_draw_start();
 void async_draw_wait();
 bool async_draw_busy(); // optional diagnostic: is a frame transfer still in flight?
@@ -50,41 +50,15 @@ static void set_pixel(int x, int y, bool value) {
 extern "C" void s_spi_post_cb(spi_transaction_t* trans);
 
 static inline spi_device_interface_config_t _devcfg = {
-        .mode           = 0,               // SPI mode 0
-        .clock_speed_hz = 6 * 1000 * 1000, // Clock out at 10 MHz
-        .spics_io_num   = SPI_DISP_CS,     // CS pin
+        .mode           = 0,                // SPI mode 0
+        .clock_speed_hz = 10 * 1000 * 1000, // Clock out at 10 MHz
+        .spics_io_num   = SPI_DISP_CS,      // CS pin
         .flags          = SPI_DEVICE_POSITIVE_CS,
-        .queue_size     = 3,
+        .queue_size     = 1,
         .pre_cb         = nullptr,
         .post_cb        = s_spi_post_cb,
 };
 extern spi_device_handle_t _spi;
-void                       ensure_clear_task(); // idempotent; called from init
 }; // namespace SMD
 
-class SMDSurface : public Surface<SMDSurface, BwPixel>, public StandardEventQueue<SMDSurface> {
-public:
-    using PixelType = BwPixel;
-
-    SMDSurface(EventLoop* loop);
-
-    ~SMDSurface() override;
-
-    void draw_pixel_impl(unsigned x, unsigned y, const BwPixel& pixel);
-
-    void clear_impl();
-
-    int get_width_impl() const;
-
-    int get_height_impl() const;
-
-    template<typename T>
-    EventHandlingResult handle(const T& event) {
-        return _window->handle(event);
-    }
-
-    EventHandlingResult handle(SurfaceResizeEvent event);
-};
-
-
 #endif // DISPLAY_HPP

Firmware/main/include/i2c_global.hpp

@@ -22,7 +22,7 @@ private:
             .scl_io_num        = I2C_SCL,
             .clk_source        = I2C_CLK_SRC_DEFAULT,
             .glitch_ignore_cnt = 7,
-            .flags             = {.enable_internal_pullup = false, .allow_pd = true},
+            .flags             = {.enable_internal_pullup = true, .allow_pd = true},
     };
     i2c_master_bus_handle_t _bus_handle;
 }; // namespace i2c_global

Firmware/main/include/spi_global.hpp

@@ -20,7 +20,7 @@ private:
                                               .sclk_io_num     = SPI_SCK,
                                               .quadwp_io_num   = -1,
                                               .quadhd_io_num   = -1,
-                                              .max_transfer_sz = 400 * 240 * 2};
+                                              .max_transfer_sz = 12482U};
 
 }; // namespace spi_global
 

Firmware/main/src/app_main.cpp

@@ -20,6 +20,7 @@
 #include <shutdowner.hpp>
 #include <spi_global.hpp>
 
+
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 
@@ -29,6 +30,160 @@
 #include "esp_sleep.h"
 #include "sdkconfig.h"
 
+#include <algorithm>
+#include <cinttypes>
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <vector>
+
+#if CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS && CONFIG_FREERTOS_USE_TRACE_FACILITY
+namespace {
+
+constexpr TickType_t kStatsTaskDelayTicks = pdMS_TO_TICKS(5000);
+constexpr TickType_t kStatsWarmupDelay    = pdMS_TO_TICKS(2000);
+constexpr UBaseType_t kStatsTaskPriority  = tskIDLE_PRIORITY + 1;
+constexpr uint32_t    kStatsTaskStack     = 4096;
+constexpr char        kStatsTaskName[]    = "TaskStats";
+
+struct TaskRuntimeSample {
+    TaskHandle_t handle;
+    uint32_t     runtime;
+};
+
+struct TaskUsageRow {
+    std::string  name;
+    uint64_t     delta;
+    UBaseType_t  priority;
+    uint32_t     stackHighWaterBytes;
+    bool         isIdle;
+};
+
+[[nodiscard]] uint64_t deltaWithWrap(uint32_t current, uint32_t previous) {
+    if (current >= previous)
+        return static_cast<uint64_t>(current - previous);
+    return static_cast<uint64_t>(current) + (static_cast<uint64_t>(UINT32_MAX) - previous) + 1ULL;
+}
+
+void task_usage_monitor(void*) {
+    static constexpr char tag[] = "TaskUsage";
+    std::vector<TaskRuntimeSample> lastSamples;
+    uint32_t                       lastTotal = 0;
+
+    vTaskDelay(kStatsWarmupDelay);
+
+    while (true) {
+        vTaskDelay(kStatsTaskDelayTicks);
+
+        const UBaseType_t taskCount = uxTaskGetNumberOfTasks();
+        if (taskCount == 0)
+            continue;
+
+        std::vector<TaskStatus_t> statusBuffer(taskCount);
+        uint32_t                  totalRuntime = 0;
+        const UBaseType_t         captured     = uxTaskGetSystemState(statusBuffer.data(), statusBuffer.size(), &totalRuntime);
+        if (captured == 0)
+            continue;
+        statusBuffer.resize(captured);
+
+        std::vector<TaskRuntimeSample> currentSamples;
+        currentSamples.reserve(statusBuffer.size());
+
+        if (lastTotal == 0) {
+            for (const auto& status: statusBuffer) {
+                currentSamples.push_back({status.xHandle, status.ulRunTimeCounter});
+            }
+            lastSamples = std::move(currentSamples);
+            lastTotal   = totalRuntime;
+            continue;
+        }
+
+        const uint64_t totalDelta = deltaWithWrap(totalRuntime, lastTotal);
+        if (totalDelta == 0)
+            continue;
+
+        std::vector<TaskUsageRow> rows;
+        rows.reserve(statusBuffer.size());
+
+        uint64_t idleDelta    = 0;
+        uint64_t activeDelta  = 0;
+        uint64_t accountedDelta = 0;
+
+        for (const auto& status: statusBuffer) {
+            const auto it = std::find_if(lastSamples.begin(), lastSamples.end(), [&](const TaskRuntimeSample& entry) {
+                return entry.handle == status.xHandle;
+            });
+
+            const uint32_t previousRuntime = (it != lastSamples.end()) ? it->runtime : status.ulRunTimeCounter;
+            const uint64_t taskDelta       = (it != lastSamples.end()) ? deltaWithWrap(status.ulRunTimeCounter, previousRuntime) : 0ULL;
+
+            currentSamples.push_back({status.xHandle, status.ulRunTimeCounter});
+
+            TaskUsageRow row{
+                    .name                 = std::string(status.pcTaskName ? status.pcTaskName : ""),
+                    .delta                = taskDelta,
+                    .priority             = status.uxCurrentPriority,
+                    .stackHighWaterBytes  = static_cast<uint32_t>(status.usStackHighWaterMark) * sizeof(StackType_t),
+                    .isIdle               = status.uxCurrentPriority == tskIDLE_PRIORITY ||
+                                            (status.pcTaskName && std::strncmp(status.pcTaskName, "IDLE", 4) == 0)
+            };
+
+            rows.push_back(std::move(row));
+
+            accountedDelta += taskDelta;
+            if (rows.back().isIdle)
+                idleDelta += taskDelta;
+            else
+                activeDelta += taskDelta;
+        }
+
+        lastSamples = std::move(currentSamples);
+        lastTotal   = totalRuntime;
+
+        if (rows.empty())
+            continue;
+
+        std::sort(rows.begin(), rows.end(), [](const TaskUsageRow& a, const TaskUsageRow& b) {
+            return a.delta > b.delta;
+        });
+
+        const double windowMs = static_cast<double>(totalDelta) / 1000.0;
+
+        std::printf("\n[%s] CPU usage over %.1f ms window\n", tag, windowMs);
+
+        for (const auto& row: rows) {
+            if (row.delta == 0 || row.isIdle)
+                continue;
+            const double pct = (static_cast<double>(row.delta) * 100.0) / static_cast<double>(totalDelta);
+            std::printf("  %-16s %6.2f%%  (prio=%u stack_free=%lu B)\n", row.name.c_str(), pct, row.priority,
+                        static_cast<unsigned long>(row.stackHighWaterBytes));
+        }
+
+        const double idlePct = (idleDelta * 100.0) / static_cast<double>(totalDelta);
+        std::printf("  %-16s %6.2f%%  (aggregated idle)\n", "<idle>", idlePct);
+
+        const uint64_t residual = (accountedDelta >= totalDelta) ? 0ULL : (totalDelta - accountedDelta);
+        if (residual > 0) {
+            const double residualPct = (static_cast<double>(residual) * 100.0) / static_cast<double>(totalDelta);
+            std::printf("  %-16s %6.2f%%  (ISRs / scheduler)\n", "<isr>", residualPct);
+        }
+
+        std::printf("[%s] Active %.2f%% | Idle %.2f%%\n", tag,
+                    (activeDelta * 100.0) / static_cast<double>(totalDelta), idlePct);
+        std::fflush(stdout);
+    }
+}
+
+void start_task_usage_monitor() {
+    xTaskCreatePinnedToCore(task_usage_monitor, kStatsTaskName, kStatsTaskStack, nullptr, kStatsTaskPriority, nullptr, 0);
+}
+
+} // namespace
+#else
+inline void start_task_usage_monitor() {}
+#endif
+
 extern "C" void app_main() {
 #ifdef CONFIG_PM_ENABLE
     // const esp_pm_config_t pm_config = {
@@ -71,5 +226,7 @@ extern "C" void app_main() {
     system.registerApp(apps::createTetrisAppFactory());
     system.registerApp(apps::createGameboyAppFactory());
 
+    start_task_usage_monitor();
+
     system.run();
 }

Firmware/main/src/app_system.cpp

@@ -1,12 +1,22 @@
 #include "app_system.hpp"
 
-#include <power_helper.hpp>
+#include <buttons.hpp>
 
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+
+#include <algorithm>
+#include <limits>
 #include <utility>
 
-AppSystem::AppSystem(AppContext ctx) : context(std::move(ctx)) {
-    context.system = this;
+namespace {
+[[nodiscard]] bool inputsDiffer(const InputState& a, const InputState& b) {
+    return a.up != b.up || a.down != b.down || a.left != b.left || a.right != b.right || a.a != b.a || a.b != b.b ||
+           a.select != b.select || a.start != b.start;
 }
+} // namespace
+
+AppSystem::AppSystem(AppContext ctx) : context(std::move(ctx)) { context.system = this; }
 
 void AppSystem::registerApp(std::unique_ptr<IAppFactory> factory) {
     if (!factory)
@@ -28,8 +38,8 @@ bool AppSystem::startAppByIndex(std::size_t index) {
         return false;
 
     context.system = this;
-    auto& factory = factories[index];
-    auto  app     = factory->create(context);
+    auto& factory  = factories[index];
+    auto  app      = factory->create(context);
     if (!app)
         return false;
 
@@ -43,7 +53,9 @@ bool AppSystem::startAppByIndex(std::size_t index) {
     context.pendingSwitch       = false;
     context.pendingSwitchByName = false;
     context.pendingAppName.clear();
-    current = std::move(app);
+    clearTimersForCurrentApp();
+    current        = std::move(app);
+    lastInputState = context.input.readState();
     current->onStart();
     return true;
 }
@@ -54,29 +66,46 @@ void AppSystem::run() {
             return;
     }
 
+    Buttons::get().register_listener(xTaskGetCurrentTaskHandle());
+    std::vector<AppEvent> events;
+    events.reserve(4);
+
     while (true) {
-        current->step();
-        if (context.pendingSwitch) {
-            const bool        byName   = context.pendingSwitchByName;
-            const std::size_t reqIndex = context.pendingAppIndex;
-            const std::string reqName  = context.pendingAppName;
-            context.pendingSwitch       = false;
-            context.pendingSwitchByName = false;
-            context.pendingAppName.clear();
-            bool switched = false;
-            if (byName) {
-                switched = startApp(reqName);
-            } else {
-                switched = startAppByIndex(reqIndex);
+        events.clear();
+        const std::uint32_t now = context.clock.millis();
+        processDueTimers(now, events);
+
+        const InputState inputNow = context.input.readState();
+        if (inputsDiffer(inputNow, lastInputState)) {
+            AppEvent evt{};
+            evt.type            = AppEventType::Button;
+            evt.timestamp_ms    = now;
+            evt.button.current  = inputNow;
+            evt.button.previous = lastInputState;
+            events.push_back(evt);
+            lastInputState = inputNow;
+        }
+
+        for (const auto& evt: events) {
+            dispatchEvent(evt);
+            if (handlePendingSwitchRequest()) {
+                break;
             }
-            if (switched)
-                continue;
         }
-        const auto now  = context.clock.millis();
-        auto       plan = current->sleepPlan(now);
-        if (plan.slow_ms || plan.normal_ms) {
-            PowerHelper::get().delay(static_cast<int>(plan.slow_ms), static_cast<int>(plan.normal_ms));
+
+
+        const std::uint32_t waitBase = context.clock.millis();
+        const std::uint32_t waitMs   = nextTimerDueMs(waitBase);
+        TickType_t          waitTicks;
+        if (waitMs == std::numeric_limits<std::uint32_t>::max()) {
+            waitTicks = portMAX_DELAY;
+        } else {
+            waitTicks = pdMS_TO_TICKS(waitMs);
+            if (waitTicks == 0)
+                waitTicks = 1;
         }
+
+        ulTaskNotifyTake(pdTRUE, waitTicks);
     }
 }
 
@@ -95,3 +124,111 @@ std::size_t AppSystem::indexOfFactory(const IAppFactory* factory) const {
     }
     return static_cast<std::size_t>(-1);
 }
+
+AppTimerHandle AppSystem::scheduleTimer(uint32_t delay_ms, bool repeat) {
+    if (!current)
+        return kInvalidAppTimer;
+    TimerRecord record;
+    record.id = nextTimerId++;
+    if (record.id == kInvalidAppTimer)
+        record.id = nextTimerId++;
+    record.generation  = currentGeneration;
+    const auto now     = context.clock.millis();
+    record.due_ms      = now + delay_ms;
+    record.interval_ms = repeat ? std::max<std::uint32_t>(1, delay_ms) : 0;
+    record.repeat      = repeat;
+    record.active      = true;
+    timers.push_back(record);
+    return record.id;
+}
+
+void AppSystem::cancelTimer(AppTimerHandle handle) {
+    auto* timer = findTimer(handle);
+    if (timer)
+        timer->active = false;
+    timers.erase(std::remove_if(timers.begin(), timers.end(), [](const TimerRecord& rec) { return !rec.active; }),
+                 timers.end());
+}
+
+void AppSystem::cancelAllTimers() {
+    for (auto& timer: timers) {
+        if (timer.generation == currentGeneration)
+            timer.active = false;
+    }
+    timers.erase(std::remove_if(timers.begin(), timers.end(), [](const TimerRecord& rec) { return !rec.active; }),
+                 timers.end());
+}
+
+void AppSystem::dispatchEvent(const AppEvent& event) {
+    if (current)
+        current->handleEvent(event);
+}
+
+void AppSystem::processDueTimers(std::uint32_t now, std::vector<AppEvent>& outEvents) {
+    for (auto& timer: timers) {
+        if (!timer.active || timer.generation != currentGeneration)
+            continue;
+        if (static_cast<std::int32_t>(now - timer.due_ms) >= 0) {
+            AppEvent ev{};
+            ev.type         = AppEventType::Timer;
+            ev.timestamp_ms = now;
+            ev.timer.handle = timer.id;
+            outEvents.push_back(ev);
+            if (timer.repeat) {
+                const std::uint32_t interval = timer.interval_ms ? timer.interval_ms : 1;
+                timer.due_ms                 = now + interval;
+            } else {
+                timer.active = false;
+            }
+        }
+    }
+    timers.erase(std::remove_if(timers.begin(), timers.end(), [](const TimerRecord& rec) { return !rec.active; }),
+                 timers.end());
+}
+
+std::uint32_t AppSystem::nextTimerDueMs(std::uint32_t now) const {
+    std::uint32_t minWait = std::numeric_limits<std::uint32_t>::max();
+    for (const auto& timer: timers) {
+        if (!timer.active || timer.generation != currentGeneration)
+            continue;
+        if (static_cast<std::int32_t>(now - timer.due_ms) >= 0)
+            return 0;
+        const std::uint32_t delta = timer.due_ms - now;
+        if (delta < minWait)
+            minWait = delta;
+    }
+    return minWait;
+}
+
+void AppSystem::clearTimersForCurrentApp() {
+    ++currentGeneration;
+    timers.clear();
+}
+
+AppSystem::TimerRecord* AppSystem::findTimer(AppTimerHandle handle) {
+    for (auto& timer: timers) {
+        if (!timer.active || timer.generation != currentGeneration)
+            continue;
+        if (timer.id == handle)
+            return &timer;
+    }
+    return nullptr;
+}
+
+bool AppSystem::handlePendingSwitchRequest() {
+    if (!context.pendingSwitch)
+        return false;
+    const bool        byName    = context.pendingSwitchByName;
+    const std::size_t reqIndex  = context.pendingAppIndex;
+    const std::string reqName   = context.pendingAppName;
+    context.pendingSwitch       = false;
+    context.pendingSwitchByName = false;
+    context.pendingAppName.clear();
+    bool switched = false;
+    if (byName) {
+        switched = startApp(reqName);
+    } else {
+        switched = startAppByIndex(reqIndex);
+    }
+    return switched;
+}

Firmware/main/src/apps/clock_app.cpp

@@ -39,43 +39,27 @@ public:
     explicit ClockApp(AppContext& ctx) : context(ctx), framebuffer(ctx.framebuffer), clock(ctx.clock) {}
 
     void onStart() override {
+        cancelRefreshTimer();
         lastSnapshot = {};
         dirty        = true;
-        renderIfNeeded(captureTime());
-    }
-
-    void step() override {
         const auto snap = captureTime();
-
-        InputState st = context.input.readState();
-
-        if (st.b && !backPrev) {
-            context.requestAppSwitchByName(kMenuAppName);
-            backPrev   = st.b;
-            selectPrev = st.select;
-            return;
-        }
-
-        if (st.select && !selectPrev) {
-            use24Hour = !use24Hour;
-            dirty     = true;
-        }
-
-        if (!sameSnapshot(snap, lastSnapshot))
-            dirty = true;
-
         renderIfNeeded(snap);
-
-        backPrev     = st.b;
-        selectPrev   = st.select;
         lastSnapshot = snap;
+        refreshTimer = context.scheduleRepeatingTimer(200);
     }
 
-    AppSleepPlan sleepPlan(uint32_t /*now*/) const override {
-        AppSleepPlan plan;
-        plan.slow_ms   = 200;
-        plan.normal_ms = 40;
-        return plan;
+    void onStop() override { cancelRefreshTimer(); }
+
+    void handleEvent(const AppEvent& event) override {
+        switch (event.type) {
+            case AppEventType::Button:
+                handleButtonEvent(event.button);
+                break;
+            case AppEventType::Timer:
+                if (event.timer.handle == refreshTimer)
+                    updateDisplay();
+                break;
+        }
     }
 
 private:
@@ -83,13 +67,44 @@ private:
     Framebuffer& framebuffer;
     Clock&       clock;
 
-    bool use24Hour  = true;
-    bool dirty      = false;
-    bool backPrev   = false;
-    bool selectPrev = false;
+    bool            use24Hour    = true;
+    bool            dirty        = false;
+    AppTimerHandle  refreshTimer = kInvalidAppTimer;
 
     TimeSnapshot lastSnapshot{};
 
+    void cancelRefreshTimer() {
+        if (refreshTimer != kInvalidAppTimer) {
+            context.cancelTimer(refreshTimer);
+            refreshTimer = kInvalidAppTimer;
+        }
+    }
+
+    void handleButtonEvent(const AppButtonEvent& button) {
+        const auto& current  = button.current;
+        const auto& previous = button.previous;
+
+        if (current.b && !previous.b) {
+            context.requestAppSwitchByName(kMenuAppName);
+            return;
+        }
+
+        if (current.select && !previous.select) {
+            use24Hour = !use24Hour;
+            dirty     = true;
+        }
+
+        updateDisplay();
+    }
+
+    void updateDisplay() {
+        const auto snap = captureTime();
+        if (!sameSnapshot(snap, lastSnapshot))
+            dirty = true;
+        renderIfNeeded(snap);
+        lastSnapshot = snap;
+    }
+
     static bool sameSnapshot(const TimeSnapshot& a, const TimeSnapshot& b) {
         return a.hasWallTime == b.hasWallTime && a.hour24 == b.hour24 && a.minute == b.minute && a.second == b.second;
     }

Firmware/main/src/apps/gameboy_app.cpp

@@ -1,13 +1,14 @@
 #pragma GCC optimize("Ofast")
 #include "apps/gameboy_app.hpp"
+#include "apps/peanut_gb.h"
 
 #include "app_framework.hpp"
+#include "app_system.hpp"
 #include "font16x8.hpp"
 
 #include <disp_tools.hpp>
 #include <fs_helper.hpp>
 
-#include <peanut_gb.h>
 
 #include "esp_timer.h"
 
@@ -26,6 +27,18 @@
 #include <sys/stat.h>
 #include <vector>
 
+#define GAMEBOY_PERF_METRICS 0
+
+#ifndef GAMEBOY_PERF_METRICS
+#define GAMEBOY_PERF_METRICS 1
+#endif
+
+#if GAMEBOY_PERF_METRICS
+#define GB_PERF_ONLY(...) __VA_ARGS__
+#else
+#define GB_PERF_ONLY(...)
+#endif
+
 namespace apps {
 namespace {
 
@@ -159,7 +172,9 @@ public:
     explicit GameboyApp(AppContext& ctx) : context(ctx), framebuffer(ctx.framebuffer) {}
 
     void onStart() override {
-        perf.resetAll();
+        cancelTick();
+        frameDelayCarryUs = 0;
+        GB_PERF_ONLY(perf.resetAll();)
         prevInput = {};
         statusMessage.clear();
         resetFpsStats();
@@ -169,37 +184,57 @@ public:
         refreshRomList();
         mode         = Mode::Browse;
         browserDirty = true;
+        scheduleNextTick(0);
     }
 
     void onStop() override {
-        perf.maybePrintAggregate(true);
+        cancelTick();
+        frameDelayCarryUs = 0;
+        GB_PERF_ONLY(perf.maybePrintAggregate(true);)
         unloadRom();
     }
 
-    void step() override {
-        perf.resetForStep();
+    void handleEvent(const AppEvent& event) override {
+        if (event.type == AppEventType::Timer && event.timer.handle == tickTimer) {
+            tickTimer                   = kInvalidAppTimer;
+            const uint64_t frameStartUs = esp_timer_get_time();
+            performStep();
+            const uint64_t frameEndUs = esp_timer_get_time();
+            const uint64_t elapsedUs  = (frameEndUs >= frameStartUs) ? (frameEndUs - frameStartUs) : 0;
+            GB_PERF_ONLY(printf("Step took %" PRIu64 " us\n", elapsedUs));
+            scheduleAfterFrame(elapsedUs);
+            return;
+        }
+        if (event.type == AppEventType::Button) {
+            frameDelayCarryUs = 0;
+            scheduleNextTick(0);
+        }
+    }
 
-        const uint64_t   inputStartUs = esp_timer_get_time();
-        const InputState input        = context.input.readState();
-        perf.inputUs                  = esp_timer_get_time() - inputStartUs;
+    void performStep() {
+        GB_PERF_ONLY(perf.resetForStep();)
+
+        GB_PERF_ONLY(const uint64_t inputStartUs = esp_timer_get_time();)
+        const InputState input = context.input.readState();
+        GB_PERF_ONLY(perf.inputUs = esp_timer_get_time() - inputStartUs;)
 
         const Mode stepMode = mode;
 
         switch (stepMode) {
             case Mode::Browse: {
-                const uint64_t handleStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t handleStartUs = esp_timer_get_time();)
                 handleBrowserInput(input);
-                perf.handleUs = esp_timer_get_time() - handleStartUs;
+                GB_PERF_ONLY(perf.handleUs = esp_timer_get_time() - handleStartUs;)
 
-                const uint64_t renderStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t renderStartUs = esp_timer_get_time();)
                 renderBrowser();
-                perf.renderUs = esp_timer_get_time() - renderStartUs;
+                GB_PERF_ONLY(perf.renderUs = esp_timer_get_time() - renderStartUs;)
                 break;
             }
             case Mode::Running: {
-                const uint64_t handleStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t handleStartUs = esp_timer_get_time();)
                 handleGameInput(input);
-                perf.handleUs = esp_timer_get_time() - handleStartUs;
+                GB_PERF_ONLY(perf.handleUs = esp_timer_get_time() - handleStartUs;)
 
                 if (!gbReady) {
                     mode         = Mode::Browse;
@@ -207,41 +242,28 @@ public:
                     break;
                 }
 
-                const uint64_t geometryStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t geometryStartUs = esp_timer_get_time();)
                 ensureRenderGeometry();
-                perf.geometryUs = esp_timer_get_time() - geometryStartUs;
+                GB_PERF_ONLY(perf.geometryUs = esp_timer_get_time() - geometryStartUs;)
 
-                const uint64_t waitStartUs = esp_timer_get_time();
-                DispTools::draw_to_display_async_wait();
-                perf.waitUs = esp_timer_get_time() - waitStartUs;
-
-                const uint64_t runStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t runStartUs = esp_timer_get_time();)
                 gb_run_frame(&gb);
-                perf.runUs = esp_timer_get_time() - runStartUs;
+                GB_PERF_ONLY(perf.runUs = esp_timer_get_time() - runStartUs;)
 
-                const uint64_t renderStartUs = esp_timer_get_time();
+                GB_PERF_ONLY(const uint64_t renderStartUs = esp_timer_get_time();)
                 renderGameFrame();
-                perf.renderUs = esp_timer_get_time() - renderStartUs;
+                GB_PERF_ONLY(perf.renderUs = esp_timer_get_time() - renderStartUs;)
                 break;
             }
         }
 
         prevInput = input;
 
-        perf.finishStep();
-        perf.accumulate();
-        perf.printStep(stepMode, gbReady, frameDirty, fpsCurrent, activeRomName, roms.size(), selectedIndex,
-                       browserDirty);
-        perf.maybePrintAggregate();
-    }
-
-    AppSleepPlan sleepPlan(uint32_t /*now*/) const override {
-        if (mode == Mode::Running)
-            return {};
-        AppSleepPlan plan;
-        plan.slow_ms   = 140;
-        plan.normal_ms = 50;
-        return plan;
+        GB_PERF_ONLY(perf.finishStep();)
+        GB_PERF_ONLY(perf.accumulate();)
+        GB_PERF_ONLY(perf.printStep(stepMode, gbReady, frameDirty, fpsCurrent, activeRomName, roms.size(),
+                                    selectedIndex, browserDirty);)
+        GB_PERF_ONLY(perf.maybePrintAggregate();)
     }
 
 private:
@@ -451,22 +473,34 @@ private:
 
     class ScopedCallbackTimer {
     public:
-        ScopedCallbackTimer(GameboyApp* instance, PerfTracker::CallbackKind kind) : app(instance), kind(kind) {
-            if (app)
+        ScopedCallbackTimer(GameboyApp* instance, PerfTracker::CallbackKind kind) {
+#if GAMEBOY_PERF_METRICS
+            if (instance) {
+                app     = instance;
+                cbKind  = kind;
                 startUs = esp_timer_get_time();
+            }
+#else
+            (void) instance;
+            (void) kind;
+#endif
         }
 
         ~ScopedCallbackTimer() {
+#if GAMEBOY_PERF_METRICS
             if (!app)
                 return;
             const uint64_t end = esp_timer_get_time();
-            app->perf.addCallback(kind, end - startUs);
+            app->perf.addCallback(cbKind, end - startUs);
+#endif
         }
 
     private:
-        GameboyApp*               app;
-        PerfTracker::CallbackKind kind;
+#if GAMEBOY_PERF_METRICS
+        GameboyApp*               app = nullptr;
+        PerfTracker::CallbackKind cbKind{};
         uint64_t                  startUs = 0;
+#endif
     };
 
     struct RenderGeometry {
@@ -484,9 +518,12 @@ private:
         std::array<int, LCD_WIDTH>  colXEnd{};
     };
 
-    AppContext&  context;
-    Framebuffer& framebuffer;
-    PerfTracker  perf{};
+    AppContext&               context;
+    Framebuffer&              framebuffer;
+    PerfTracker               perf{};
+    AppTimerHandle            tickTimer         = kInvalidAppTimer;
+    int64_t                   frameDelayCarryUs = 0;
+    static constexpr uint32_t kTargetFrameUs    = 1000000 / 60; // ~16.6 ms
 
     Mode                  mode          = Mode::Browse;
     ScaleMode             scaleMode     = ScaleMode::Original;
@@ -505,13 +542,47 @@ private:
     const uint8_t*       romDataView     = nullptr;
     std::size_t          romDataViewSize = 0;
     std::vector<uint8_t> cartRam;
-    bool                 frameDirty      = false;
-    uint32_t             fpsLastSampleMs = 0;
-    uint32_t             fpsFrameCounter = 0;
-    uint32_t             fpsCurrent      = 0;
+    bool                 frameDirty        = false;
+    uint32_t             fpsLastSampleMs   = 0;
+    uint32_t             fpsFrameCounter   = 0;
+    uint32_t             totalFrameCounter = 0;
+    uint32_t             fpsCurrent        = 0;
     std::string          activeRomName;
     std::string          activeRomSavePath;
 
+    void cancelTick() {
+        if (tickTimer != kInvalidAppTimer) {
+            context.cancelTimer(tickTimer);
+            tickTimer = kInvalidAppTimer;
+        }
+    }
+
+    void scheduleNextTick(uint32_t delayMs) {
+        cancelTick();
+        tickTimer = context.scheduleTimer(delayMs, false);
+    }
+
+    uint32_t idleDelayMs() const { return browserDirty ? 50 : 140; }
+
+    void scheduleAfterFrame(uint64_t elapsedUs) {
+        if (mode == Mode::Running && gbReady) {
+            int64_t desiredUs = static_cast<int64_t>(kTargetFrameUs) - static_cast<int64_t>(elapsedUs);
+            desiredUs += frameDelayCarryUs;
+            if (desiredUs <= 0) {
+                frameDelayCarryUs = desiredUs;
+                scheduleNextTick(0);
+                return;
+            }
+            frameDelayCarryUs = desiredUs % 1000;
+            desiredUs -= frameDelayCarryUs;
+            uint32_t delayMs = static_cast<uint32_t>(desiredUs / 1000);
+            scheduleNextTick(delayMs);
+            return;
+        }
+        frameDelayCarryUs = 0;
+        scheduleNextTick(idleDelayMs());
+    }
+
     bool ensureFilesystemReady() {
         esp_err_t err = FsHelper::get().mount();
         if (err != ESP_OK) {
@@ -866,13 +937,14 @@ private:
             return false;
         }
 
-        gb.direct.priv       = this;
-        gb.direct.joypad     = 0xFF;
-        gb.direct.interlace  = false;
-        gb.direct.frame_skip = false;
+        gb.direct.priv   = this;
+        gb.direct.joypad = 0xFF;
 
         gb_init_lcd(&gb, &GameboyApp::lcdDrawLine);
 
+        gb.direct.interlace  = false;
+        gb.direct.frame_skip = true;
+
         const uint_fast32_t saveSize = gb_get_save_size(&gb);
         cartRam.assign(static_cast<std::size_t>(saveSize), 0);
         std::string savePath;
@@ -971,6 +1043,7 @@ private:
         ensureRenderGeometry();
 
         ++fpsFrameCounter;
+        ++totalFrameCounter;
         const uint32_t nowMs = context.clock.millis();
         if (fpsLastSampleMs == 0)
             fpsLastSampleMs = nowMs;
@@ -982,9 +1055,11 @@ private:
             fpsLastSampleMs             = nowMs;
         }
 
-        char fpsBuf[16];
-        std::snprintf(fpsBuf, sizeof(fpsBuf), "%u FPS", static_cast<unsigned>(fpsCurrent));
-        const std::string fpsText(fpsBuf);
+        char fpsValueBuf[16];
+        std::snprintf(fpsValueBuf, sizeof(fpsValueBuf), "%u", static_cast<unsigned>(fpsCurrent));
+        const std::string fpsValue(fpsValueBuf);
+        const std::string fpsLabel  = "FPS";
+        const std::string fpsText   = fpsValue + " FPS";
         const std::string scaleHint = (scaleMode == ScaleMode::FullHeight) ? "START+B NORMAL" : "START+B SCALE";
 
         if (scaleMode == ScaleMode::FullHeight) {
@@ -998,46 +1073,69 @@ private:
             const int   maxLeftX      = std::max(0, screenWidth - rotatedWidth);
             const int   maxRightXBase = std::max(0, screenWidth - rotatedWidth);
 
+
+            const int horizontalPadding = 8;
+            const int fpsLineGap        = 4;
+            const int fpsLabelWidth     = font16x8::measureText(fpsLabel, 1, 1);
+            const int fpsValueWidth     = font16x8::measureText(fpsValue, 1, 1);
+            const int fpsBlockWidth     = std::max(fpsLabelWidth, fpsValueWidth);
+            int       fpsX              = std::max(0, screenWidth - fpsBlockWidth - horizontalPadding);
+            const int fpsY              = horizontalPadding;
+            font16x8::drawText(framebuffer, fpsX, fpsY, fpsLabel, 1, true, 1);
+            font16x8::drawText(framebuffer, fpsX, fpsY + font16x8::kGlyphHeight + fpsLineGap, fpsValue, 1, true, 1);
+            const int reservedTop = fpsY + (font16x8::kGlyphHeight * 2) + fpsLineGap + horizontalPadding;
+
             if (!activeRomName.empty()) {
-                const int textHeight = measureVerticalText(activeRomName, textScale);
-                const int maxOrigin  = std::max(0, screenHeight - textHeight);
-                int       leftX      = std::clamp((leftMargin - rotatedWidth) / 2, 0, maxLeftX);
-                int       leftY      = std::clamp((screenHeight - textHeight) / 2, 0, maxOrigin);
-                drawTextRotated(framebuffer, leftX, leftY, activeRomName, false, textScale, true, 1);
+                const std::string rotatedRomName(activeRomName.rbegin(), activeRomName.rend());
+                const int         textHeight = measureVerticalText(rotatedRomName, textScale);
+                const int         maxOrigin  = std::max(0, screenHeight - textHeight);
+                int               leftX      = 8;
+                int               leftY      = std::clamp((screenHeight - textHeight) / 2, 0, maxOrigin);
+                drawTextRotated(framebuffer, leftX, leftY, rotatedRomName, true, textScale, true, 1);
+                if (!statusMessage.empty()) {
+                    const std::string rotatedStatusMessage(statusMessage.rbegin(), statusMessage.rend());
+                    const int         textHeight = measureVerticalText(rotatedStatusMessage, textScale);
+                    const int         maxOrigin  = std::max(0, screenHeight - textHeight);
+                    leftX                        = leftX + 20;
+                    leftY                        = std::clamp((screenHeight - textHeight) / 2, 0, maxOrigin);
+                    drawTextRotated(framebuffer, leftX, leftY, rotatedStatusMessage, true, textScale, true, 1);
+                }
             }
 
-            const int  gap              = 8;
-            int        totalRight       = 0;
-            const auto accumulateHeight = [&](std::string_view text) {
-                if (text.empty())
-                    return;
-                if (totalRight > 0)
-                    totalRight += gap;
-                totalRight += measureVerticalText(text, textScale);
-            };
-            accumulateHeight(fpsText);
-            accumulateHeight("START+SELECT BACK");
-            accumulateHeight(scaleHint);
-            if (!statusMessage.empty())
-                accumulateHeight(statusMessage);
 
-            const int maxRightOrigin = std::max(0, screenHeight - totalRight);
-            int       rightY         = std::clamp((screenHeight - totalRight) / 2, 0, maxRightOrigin);
-            int       rightX         = screenWidth - rightMargin + std::max(0, (rightMargin - rotatedWidth) / 2);
-            rightX                   = std::clamp(rightX, 0, maxRightXBase);
+            std::vector<std::string_view> rightTexts;
+            rightTexts.reserve(2U);
+            rightTexts.emplace_back("START+SELECT BACK");
+            rightTexts.emplace_back(scaleHint);
 
-            const auto drawRight = [&](std::string_view text) {
+            const int gap              = 8;
+            int       totalRightHeight = 0;
+            for (std::string_view text: rightTexts) {
                 if (text.empty())
-                    return;
-                drawTextRotated(framebuffer, rightX, rightY, text, true, textScale, true, 1);
-                rightY += measureVerticalText(text, textScale);
-                rightY += gap;
-            };
-            drawRight(fpsText);
-            drawRight("START+SELECT BACK");
-            drawRight(scaleHint);
-            if (!statusMessage.empty())
-                drawRight(statusMessage);
+                    continue;
+                std::string rotated(text.rbegin(), text.rend());
+                if (totalRightHeight > 0)
+                    totalRightHeight += gap;
+                totalRightHeight += measureVerticalText(rotated, textScale);
+            }
+
+            const int maxRightOrigin = std::max(0, screenHeight - totalRightHeight);
+            int       rightY         = std::clamp((screenHeight - totalRightHeight) / 2, 0, maxRightOrigin);
+            if (rightY < reservedTop)
+                rightY = std::min(std::max(reservedTop, 0), maxRightOrigin);
+
+            int rightX = screenWidth - 20;
+
+            for (size_t i = 0; i < rightTexts.size(); ++i) {
+                std::string_view text = rightTexts[i];
+                if (text.empty())
+                    continue;
+                std::string rotated(text.rbegin(), text.rend());
+                rightY = screenHeight - measureVerticalText(rotated, textScale) - 8;
+                drawTextRotated(framebuffer, rightX, rightY, rotated, true, textScale, true, 1);
+                rightX -= 20;
+            }
+
         } else {
             if (!activeRomName.empty())
                 font16x8::drawText(framebuffer, 16, 16, activeRomName, 1, true, 1);
@@ -1054,8 +1152,8 @@ private:
 
             if (!statusMessage.empty()) {
                 const int statusWidth = font16x8::measureText(statusMessage, 1, 1);
-                const int statusX     = std::max(12, (framebuffer.width() - statusWidth) / 2);
-                const int statusY     = std::max(16, instructionY - font16x8::kGlyphHeight - 4);
+                const int statusX     = std::max(12, (framebuffer.width() - statusWidth) - 12);
+                const int statusY     = instructionY;
                 font16x8::drawText(framebuffer, statusX, statusY, statusMessage, 1, true, 1);
             }
         }
@@ -1127,6 +1225,19 @@ private:
         return static_cast<GameboyApp*>(gb->direct.priv);
     }
 
+    static bool shouldPixelBeOn(int value, int dstX, int dstY, bool useDither) {
+        value &= 0x03;
+        if (!useDither)
+            return value >= 2;
+        if (value >= 3)
+            return true;
+        if (value <= 0)
+            return false;
+        constexpr uint8_t pattern[2][2] = {{0, 2}, {3, 1}};
+        const uint8_t     threshold     = pattern[dstY & 0x01][dstX & 0x01];
+        return value > threshold;
+    }
+
     static uint8_t romRead(struct gb_s* gb, const uint_fast32_t addr) {
         auto* self = fromGb(gb);
         if (!self)
@@ -1169,7 +1280,8 @@ private:
         self->unloadRom();
     }
 
-    static void lcdDrawLine(struct gb_s* gb, const uint8_t pixels[160], const uint_fast8_t line) {
+    __attribute__((optimize("Ofast"))) static void lcdDrawLine(struct gb_s* gb, const uint8_t pixels[160],
+                                                               const uint_fast8_t line) {
         auto* self = fromGb(gb);
         if (!self || line >= LCD_HEIGHT)
             return;
@@ -1190,11 +1302,19 @@ private:
 
         Framebuffer& fb = self->framebuffer;
 
+        GB_PERF_ONLY(const uint64_t waitStartUs = esp_timer_get_time();)
+        DispTools::draw_to_display_async_wait();
+        GB_PERF_ONLY(self->perf.waitUs = esp_timer_get_time() - waitStartUs;)
+
+        const bool useDither = (self->scaleMode == ScaleMode::FullHeight) &&
+                               (geom.scaledWidth != LCD_WIDTH || geom.scaledHeight != LCD_HEIGHT);
+
         if (geom.scaledWidth == LCD_WIDTH && geom.scaledHeight == LCD_HEIGHT) {
             const int dstY     = yStart;
             const int dstXBase = geom.offsetX;
             for (int x = 0; x < LCD_WIDTH; ++x) {
-                const bool on = (pixels[x] & 0x03u) >= 2;
+                const int  val = (pixels[x] & 0x03u);
+                const bool on  = shouldPixelBeOn(val, dstXBase + x, dstY, useDither);
                 fb.drawPixel(dstXBase + x, dstY, on);
             }
             return;
@@ -1207,10 +1327,11 @@ private:
             const int drawEnd   = colEnd[x];
             if (drawStart >= drawEnd)
                 continue;
-            const bool on = (pixels[x] & 0x03u) >= 2;
             for (int dstY = yStart; dstY < yEnd; ++dstY)
-                for (int dstX = drawStart; dstX < drawEnd; ++dstX)
+                for (int dstX = drawStart; dstX < drawEnd; ++dstX) {
+                    const bool on = shouldPixelBeOn(pixels[x], dstX, dstY, useDither);
                     fb.drawPixel(dstX, dstY, on);
+                }
         }
     }
 

Firmware/main/src/apps/menu_app.cpp

@@ -32,45 +32,33 @@ public:
         renderIfNeeded();
     }
 
-    void step() override {
-        InputState st = context.input.readState();
+    void handleEvent(const AppEvent& event) override {
+        if (event.type != AppEventType::Button)
+            return;
 
-        if (st.left && !leftPrev) {
+        const auto& current = event.button.current;
+        const auto& previous = event.button.previous;
+
+        if (current.left && !previous.left) {
             moveSelection(-1);
-        } else if (st.right && !rightPrev) {
+        } else if (current.right && !previous.right) {
             moveSelection(+1);
         }
 
-        const bool launch = (st.a && !rotatePrev) || (st.select && !selectPrev);
+        const bool launch = (current.a && !previous.a) || (current.select && !previous.select);
         if (launch)
             launchSelected();
 
-        leftPrev   = st.left;
-        rightPrev  = st.right;
-        rotatePrev = st.a;
-        selectPrev = st.select;
-
         renderIfNeeded();
     }
 
-    AppSleepPlan sleepPlan(uint32_t /*now*/) const override {
-        AppSleepPlan plan;
-        plan.slow_ms   = 120;
-        plan.normal_ms = 40;
-        return plan;
-    }
-
 private:
     AppContext&            context;
     Framebuffer&           framebuffer;
     std::vector<MenuEntry> entries;
     std::size_t            selected = 0;
 
-    bool dirty      = false;
-    bool leftPrev   = false;
-    bool rightPrev  = false;
-    bool rotatePrev = false;
-    bool selectPrev = false;
+    bool dirty = false;
 
     void moveSelection(int step) {
         if (entries.empty())

Firmware/main/src/apps/tetris_app.cpp

@@ -4,6 +4,7 @@
 #include "apps/tetris_app.hpp"
 
 #include "app_framework.hpp"
+#include "app_system.hpp"
 #include "apps/menu_app.hpp"
 #include "font16x8.hpp"
 
@@ -1149,17 +1150,51 @@ namespace {
 
 class TetrisApp final : public IApp {
 public:
-    explicit TetrisApp(AppContext& ctx) : game(ctx) {}
+    explicit TetrisApp(AppContext& ctx) : context(ctx), game(ctx) {}
 
-    void step() override { game.step(); }
+    void onStart() override {
+        cancelTick();
+        scheduleNextTick(0);
+    }
 
-    AppSleepPlan sleepPlan(uint32_t now) const override {
-        auto plan = game.recommendedSleepMs(now);
-        return {plan.slow_ms, plan.normal_ms};
+    void onStop() override { cancelTick(); }
+
+    void handleEvent(const AppEvent& event) override {
+        if (event.type == AppEventType::Timer && event.timer.handle == tickTimer) {
+            tickTimer = kInvalidAppTimer;
+            runStep();
+            return;
+        }
+        if (event.type == AppEventType::Button) {
+            scheduleNextTick(0);
+        }
     }
 
 private:
-    tetris::Game game;
+    AppContext&    context;
+    tetris::Game   game;
+    AppTimerHandle tickTimer = kInvalidAppTimer;
+
+    void runStep() {
+        game.step();
+        const auto now  = context.clock.millis();
+        const auto plan = game.recommendedSleepMs(now);
+        uint32_t delay = plan.normal_ms != 0 ? plan.normal_ms : plan.slow_ms;
+        scheduleNextTick(delay);
+    }
+
+    void scheduleNextTick(uint32_t delayMs) {
+        if (tickTimer != kInvalidAppTimer)
+            context.cancelTimer(tickTimer);
+        tickTimer = context.scheduleTimer(delayMs, false);
+    }
+
+    void cancelTick() {
+        if (tickTimer != kInvalidAppTimer) {
+            context.cancelTimer(tickTimer);
+            tickTimer = kInvalidAppTimer;
+        }
+    }
 };
 
 class TetrisAppFactory final : public IAppFactory {

Firmware/main/src/buttons.cpp

@@ -19,7 +19,7 @@ static i2c_master_dev_handle_t    dev_handle;
 static inline i2c_device_config_t dev_cfg = {
         .dev_addr_length = I2C_ADDR_BIT_LEN_7,
         .device_address  = 0x20,
-        .scl_speed_hz    = 100000,
+        .scl_speed_hz    = 50000,
 };
 
 Buttons& Buttons::get() {
@@ -62,7 +62,7 @@ Buttons::Buttons() {
     buf2[0] = 7;
     buf2[1] = 0x80;
     ESP_ERROR_CHECK(i2c_master_transmit(dev_handle, buf2, sizeof(buf2), -1));
-    xTaskCreate(&start_pooler, "ButtonsPooler", 2048, this, 1, &_pooler_task);
+    xTaskCreate(&start_pooler, "ButtonsPooler", 2048, this, 2, &_pooler_task);
 
     ESP_ERROR_CHECK(gpio_reset_pin(EXP_INT));
     ESP_ERROR_CHECK(gpio_set_direction(EXP_INT, GPIO_MODE_INPUT));
@@ -90,7 +90,11 @@ void Buttons::pooler() {
         reg = 1;
         ESP_ERROR_CHECK(
                 i2c_master_transmit_receive(dev_handle, &reg, sizeof(reg), reinterpret_cast<uint8_t*>(&buffer), 1, -1));
+        if (_listener)
+            xTaskNotifyGive(_listener);
     }
 }
 uint8_t Buttons::get_pressed() { return _current; }
 void    Buttons::install_isr() { gpio_isr_handler_add(EXP_INT, wakeup, nullptr); }
+
+void Buttons::register_listener(TaskHandle_t task) { _listener = task; }

Firmware/main/src/display.cpp

@@ -1,46 +1,49 @@
-// Simplified display implementation (no async memcpy) ---------------------------------
+// Double-buffered display implementation with async memcpy ---------------------------------
 
 #include "display.hpp"
+#include <cassert>
 #include <cstring>
 #include <driver/gpio.h>
 #include "disp_tools.hpp"
 #include "driver/spi_master.h"
 #include "esp_async_memcpy.h"
+#include "esp_timer.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/semphr.h"
 #include "freertos/task.h"
 
-DMA_ATTR uint8_t SMD::dma_buf[SMD::kLineDataBytes]{};
-DMA_ATTR uint8_t dma_buf_template[SMD::kLineDataBytes]{};
+DMA_ATTR static uint8_t s_dma_buffer0[SMD::kLineDataBytes]{};
+DMA_ATTR static uint8_t s_dma_buffer1[SMD::kLineDataBytes]{};
+static uint8_t*         s_dma_buffers[2] = {s_dma_buffer0, s_dma_buffer1};
+DMA_ATTR static uint8_t dma_buf_template[SMD::kLineDataBytes]{};
+
+uint8_t* SMD::dma_buf = s_dma_buffers[0];
 
 spi_device_handle_t SMD::_spi;
 
 static spi_transaction_t _tx{};
+static SemaphoreHandle_t _txSem            = nullptr;
 static bool              _vcom             = false;
-volatile bool            _inFlight         = false;
 static TaskHandle_t      s_clearTaskHandle = nullptr;
 static SemaphoreHandle_t s_clearReqSem     = nullptr;
-static SemaphoreHandle_t s_clearSem        = nullptr;
+static SemaphoreHandle_t s_bufferSem[2]    = {nullptr, nullptr};
 
 static async_memcpy_config_t config = ASYNC_MEMCPY_DEFAULT_CONFIG();
 // update the maximum data stream supported by underlying DMA engine
-static async_memcpy_handle_t driver = NULL;
+static async_memcpy_handle_t driver = nullptr;
+
+static volatile int s_drawBufIdx = 0;
 
 static unsigned char reverse_bits3(unsigned char b) { return (b * 0x0202020202ULL & 0x010884422010ULL) % 0x3ff; }
 
-
-static bool IRAM_ATTR my_async_memcpy_cb(async_memcpy_handle_t mcp_hdl, async_memcpy_event_t* event, void* cb_args) {
+static bool IRAM_ATTR my_async_memcpy_cb(async_memcpy_handle_t /*mcp_hdl*/, async_memcpy_event_t* /*event*/,
+                                         void* cb_args) {
     BaseType_t high_task_wakeup = pdFALSE;
-    _inFlight                   = false;
-    xSemaphoreGiveFromISR(s_clearSem,
-                          &high_task_wakeup); // high_task_wakeup set to pdTRUE if some high priority task unblocked
+    auto       sem              = static_cast<SemaphoreHandle_t>(cb_args);
+    xSemaphoreGiveFromISR(sem, &high_task_wakeup);
     return high_task_wakeup == pdTRUE;
 }
 
-static void zero_framebuffer_payload() {
-    ESP_ERROR_CHECK(esp_async_memcpy(driver, SMD::dma_buf, dma_buf_template, 12480, my_async_memcpy_cb, nullptr));
-}
-
 extern "C" void IRAM_ATTR s_spi_post_cb(spi_transaction_t* /*t*/) {
     BaseType_t hpw = pdFALSE;
     xSemaphoreGiveFromISR(s_clearReqSem, &hpw);
@@ -51,87 +54,92 @@ extern "C" void IRAM_ATTR s_spi_post_cb(spi_transaction_t* /*t*/) {
 static void clear_task(void*) {
     for (;;) {
         if (xSemaphoreTake(s_clearReqSem, portMAX_DELAY) == pdTRUE) {
-            printf("Started zeroing\n");
             spi_transaction_t* r = nullptr;
             ESP_ERROR_CHECK(spi_device_get_trans_result(SMD::_spi, &r, 0));
-            zero_framebuffer_payload();
-            // printf("Zeroing done\n");
+            int bufIdx = (int) r->user;
+            xSemaphoreGive(_txSem);
+            ESP_ERROR_CHECK(esp_async_memcpy(driver, s_dma_buffers[bufIdx], dma_buf_template, 12480U,
+                                             my_async_memcpy_cb, static_cast<void*>(s_bufferSem[bufIdx])));
         }
     }
 }
 
-void SMD::ensure_clear_task() {
-    if (!s_clearReqSem)
-        s_clearReqSem = xSemaphoreCreateBinary();
-    if (!s_clearSem)
-        s_clearSem = xSemaphoreCreateBinary();
-    xSemaphoreGive(s_clearSem);
-
-    if (!s_clearTaskHandle)
-        xTaskCreatePinnedToCore(clear_task, "fbclr", 1536, nullptr, tskIDLE_PRIORITY + 1, &s_clearTaskHandle, 0);
-}
-
-
 void SMD::init() {
     spi_bus_add_device(SPI_BUS, &_devcfg, &_spi);
-    ensure_clear_task();
     ESP_ERROR_CHECK(gpio_reset_pin(SPI_DISP_DISP));
     ESP_ERROR_CHECK(gpio_set_direction(SPI_DISP_DISP, GPIO_MODE_OUTPUT));
     ESP_ERROR_CHECK(gpio_set_level(SPI_DISP_DISP, 1));
     ESP_ERROR_CHECK(gpio_hold_en(SPI_DISP_DISP));
-    for (uint8_t i = 0; i < DISP_HEIGHT; i++) {
-        dma_buf[kLineMultiSingle * i + 1]              = reverse_bits3(i + 1);
-        dma_buf[2 + kLineMultiSingle * i + kLineBytes] = 0;
+    for (int buf = 0; buf < 2; ++buf) {
+        auto* fb = s_dma_buffers[buf];
+        for (uint8_t i = 0; i < DISP_HEIGHT; ++i) {
+            fb[kLineMultiSingle * i + 1]              = reverse_bits3(i + 1);
+            fb[2 + kLineMultiSingle * i + kLineBytes] = 0;
+        }
+        fb[kLineDataBytes - 1] = 0;
     }
-    dma_buf[kLineDataBytes - 1] = 0;
+
+    s_drawBufIdx = 0;
+    dma_buf      = s_dma_buffers[s_drawBufIdx];
+
     for (int y = 0; y < DISP_HEIGHT; ++y)
         for (int x = 0; x < DISP_WIDTH; ++x)
-            DispTools::set_pixel(x, y, false);
+            set_pixel(x, y, false);
+
     std::memcpy(dma_buf_template, dma_buf, sizeof(dma_buf_template));
+    std::memcpy(s_dma_buffers[1], dma_buf_template, sizeof(dma_buf_template));
     ESP_ERROR_CHECK(esp_async_memcpy_install(&config, &driver)); // install driver with default DMA engine
+
+    s_clearReqSem = xSemaphoreCreateBinary();
+    for (int i = 0; i < 2; ++i) {
+        s_bufferSem[i] = xSemaphoreCreateBinary();
+        xSemaphoreGive(s_bufferSem[i]);
+    }
+
+    _txSem = xSemaphoreCreateBinary();
+    xSemaphoreGive(_txSem);
+    xTaskCreate(clear_task, "fbclr", 1536, nullptr, tskIDLE_PRIORITY + 1, &s_clearTaskHandle);
 }
 
-bool SMD::async_draw_busy() { return _inFlight; }
+bool SMD::async_draw_busy() { return uxSemaphoreGetCount(s_bufferSem[s_drawBufIdx]) == 0; }
 
 void SMD::async_draw_start() {
-    assert(!_inFlight);
-    if (!xSemaphoreTake(s_clearSem, portMAX_DELAY))
+    assert(driver != nullptr);
+    if (!xSemaphoreTake(_txSem, portMAX_DELAY))
         assert(false);
-    _vcom         = !_vcom;
-    _tx           = {};
-    _tx.tx_buffer = dma_buf;
-    _tx.length    = SMD::kLineDataBytes * 8;
-    dma_buf[0]    = 0b10000000 | (_vcom << 6);
-    _inFlight     = true;
+
+    const int sendIdx = s_drawBufIdx;
+    assert(sendIdx >= 0 && sendIdx < 2);
+
+    SemaphoreHandle_t sem = s_bufferSem[sendIdx];
+    if (!xSemaphoreTake(sem, 0))
+        assert(false);
+
+    const int nextDrawIdx = sendIdx ^ 1;
+
+    _vcom                     = !_vcom;
+    _tx                       = {};
+    _tx.tx_buffer             = s_dma_buffers[sendIdx];
+    _tx.length                = SMD::kLineDataBytes * 8;
+    _tx.user                  = (void*) (sendIdx);
+    s_dma_buffers[sendIdx][0] = 0b10000000 | (_vcom << 6);
     ESP_ERROR_CHECK(spi_device_queue_trans(_spi, &_tx, 0));
+
+    s_drawBufIdx = nextDrawIdx;
+    dma_buf      = s_dma_buffers[nextDrawIdx];
 }
 
 void SMD::async_draw_wait() {
-    if (!_inFlight || uxSemaphoreGetCount(s_clearSem)) {
-        // assert((uxSemaphoreGetCount(s_clearSem) == 0) == _inFlight);
-        return;
+    SemaphoreHandle_t sem = s_bufferSem[s_drawBufIdx];
+    // uint64_t          waitedUs = 0;
+    if (!uxSemaphoreGetCount(sem)) {
+        // uint64_t start = esp_timer_get_time();
+        if (!xSemaphoreTake(sem, portMAX_DELAY))
+            assert(false);
+        if (!xSemaphoreGive(sem))
+            assert(false);
+        // waitedUs = esp_timer_get_time() - start;
     }
-    if (!xSemaphoreTake(s_clearSem, portMAX_DELAY))
-        assert(false);
-    if (!xSemaphoreGive(s_clearSem))
-        assert(false);
-    assert(!_inFlight);
+    // if (waitedUs)
+    //     printf("Waited %" PRIu64 " us\n", waitedUs);
 }
-
-// (clear_in_progress / wait_clear / request_clear removed from public API)
-
-// Surface implementation ------------------------------------------------------
-void SMDSurface::draw_pixel_impl(unsigned x, unsigned y, const BwPixel& pixel) {
-    if (pixel.on)
-        DispTools::set_pixel(x, y);
-    else
-        DispTools::reset_pixel(x, y);
-}
-void                SMDSurface::clear_impl() { DispTools::clear(); }
-int                 SMDSurface::get_width_impl() const { return DISP_WIDTH; }
-int                 SMDSurface::get_height_impl() const { return DISP_HEIGHT; }
-EventHandlingResult SMDSurface::handle(SurfaceResizeEvent event) { return _window->handle(event); }
-SMDSurface::SMDSurface(EventLoop* loop) :
-    Surface<SMDSurface, BwPixel>(),
-    EventQueue<SMDSurface, KeyboardEvent, SurfaceEvent, SurfaceResizeEvent>(loop, this) {}
-SMDSurface::~SMDSurface() {}

Firmware/sdkconfig

@@ -1699,9 +1699,13 @@ CONFIG_FREERTOS_TIMER_TASK_STACK_DEPTH=2048
 CONFIG_FREERTOS_TIMER_QUEUE_LENGTH=10
 CONFIG_FREERTOS_QUEUE_REGISTRY_SIZE=0
 CONFIG_FREERTOS_TASK_NOTIFICATION_ARRAY_ENTRIES=1
-# CONFIG_FREERTOS_USE_TRACE_FACILITY is not set
+CONFIG_FREERTOS_USE_TRACE_FACILITY=y
+CONFIG_FREERTOS_USE_STATS_FORMATTING_FUNCTIONS=y
 # CONFIG_FREERTOS_USE_LIST_DATA_INTEGRITY_CHECK_BYTES is not set
-# CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS is not set
+# CONFIG_FREERTOS_VTASKLIST_INCLUDE_COREID is not set
+CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS=y
+CONFIG_FREERTOS_RUN_TIME_COUNTER_TYPE_U32=y
+# CONFIG_FREERTOS_RUN_TIME_COUNTER_TYPE_U64 is not set
 CONFIG_FREERTOS_USE_TICKLESS_IDLE=y
 CONFIG_FREERTOS_IDLE_TIME_BEFORE_SLEEP=3
 # CONFIG_FREERTOS_USE_APPLICATION_TASK_TAG is not set
@@ -1721,6 +1725,7 @@ CONFIG_FREERTOS_TICK_SUPPORT_SYSTIMER=y
 CONFIG_FREERTOS_CORETIMER_SYSTIMER_LVL1=y
 # CONFIG_FREERTOS_CORETIMER_SYSTIMER_LVL3 is not set
 CONFIG_FREERTOS_SYSTICK_USES_SYSTIMER=y
+CONFIG_FREERTOS_RUN_TIME_STATS_USING_ESP_TIMER=y
 # CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH is not set
 # CONFIG_FREERTOS_CHECK_PORT_CRITICAL_COMPLIANCE is not set
 # end of Port