Memory management and FreeRTOS context for the Megahub ESP32 project. Use when dealing with heap allocation, stack size, task creation, inter-task communication, semaphores, queues, or any ESP32 memory constraints.
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See how to installReview the instructions the agent will receive before you install.
| Point in startup | Free heap |
|---|---|
| After IMU init | ~170 KB |
| After Lua state creation | ~140 KB |
| After LEGO motor init | ~140 KB |
| After configuration load | ~139 KB |
| After BT stack start | ~76 KB |
| After BLE characteristics setup | ~76 KB |
| During BLE connection (connected) | ~63–73 KB |
PSRAM: ~4.1 MB available (confirmed present on this board — ESP.getFreePsram()).
BT stack alone consumes ~65 KB of heap. Every BLE connection consumes an additional ~30 KB.
static, heap, or PSRAM.new/malloc. Every allocation needs a matching delete/free.String += loops. Prefer std::string::reserve() or fixed char[] buffers.const and PROGMEM for large constant data to keep it in flash.Known tasks and their stack high-water marks (from real device logs):
| Task | Priority | Stack HWM (words) | Notes |
|---|---|---|---|
loopTask | 1 | 272 | Arduino main loop |
BTMsgProcessor | 2 | 2968–7528 | Processes BLE messages |
HIDEventTask | 5 | 1920 | Classic BT HID events |
PortStatus | 1 | 1420 | LEGO port status reporting |
StatusMonitor | 1 | 2452 | Heap/task monitoring |
Device monitor | 1 | 1776 | Lua thread for device monitoring |
BTU_TASK | 20 | 3624–4988 | BT stack internal |
BTC_TASK | 19 | 4328–4364 | BT stack internal |
hciT | 22 | 1516–1544 | BT HCI layer |
btController | 23 | 2088 | BT controller |
esp_timer | 22 | 4048 | ESP timer service |
ipc0/1 | 24 | 356/476 | IPC (highest priority) |
⚠ loopTask HWM of 272 words is critically low — avoid adding stack usage to the main loop.
xSemaphoreTake with a timeout — never block indefinitelyuxTaskGetStackHighWaterMark(). Stack overflow = silent crash.// Log heap + PSRAM
INFO("Free heap: %d bytes, Free PSRAM: %d bytes",
ESP.getFreeHeap(), ESP.getFreePsram());
// Log task stack (for current task)
INFO("Stack HWM: %d words", uxTaskGetStackHighWaterMark(NULL));
// Log all task stacks (use vTaskList for full snapshot)
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Bluetooth context for the Megahub project. Use when working on BLE GATT server, Classic Bluetooth HID host, Web Bluetooth API integration, btremote library, connection handling, or any Bluetooth-related firmware code.
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Blockly visual programming context for the Megahub project. Use when adding, modifying, or debugging custom Blockly blocks, the Lua code generator, the toolbox, block colors, or the BLOCKS.md documentation generation script.
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Documentation structure and maintenance rules for the Megahub project. Use whenever making user-facing changes — adding features, changing behavior, fixing hardware compatibility, or modifying configuration. Describes which files to update, the README structure, and writing style.
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Core firmware context for the Megahub ESP32 project. Use when working on PlatformIO configuration, build scripts, library structure, main.cpp, or general ESP32 firmware development. Covers build system, project structure, common pitfalls, and debugging.
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Frontend development context for the Megahub project. Use when working on the web-based IDE, Vite build system, Blockly visual programming, Web Bluetooth API integration, JavaScript frontend code, CSS/styles, UI components, or anything in the /frontend/ directory.
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LEGO Powered Up protocol context for the Megahub project. Use when working on LEGO device communication, lpfuart library, UART parsing, motor control, sensor modes, device initialization, or debugging UART noise/corruption issues.
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