$ show emuflight/EmuFlight
EmuFlight is a real-time embedded flight controller firmware for multirotor drones, forked from Betaflight/Cleanflight. It runs on STM32F4/F7/H7 microcontrollers, providing sensor fusion (gyro, accelerometer, barometer, GPS), PID control, motor mixing, telemetry, and on-screen display. The architecture is bare-metal with a cooperative scheduler, modular driver abstraction (vtable patterns for serial ports, displays, VTX, sensors), and a persistent parameter group (PG) configuration system. Key data flows: sensor inputs → Kalman/dynamic notch filters → PID → mixer → motor outputs; RC input via various protocols; telemetry/blackbox logging output. External dependencies include STM32 HAL, CMSIS DSP, and MAVLink libraries. The codebase is well-structured with unit tests (Google Test) and CI, though it retains some legacy drivers and conditional complexity from the Betaflight lineage.
The LLM identified 3 files worth highlighting for reuse:
The Parameter Group (PG) system provides a macro-driven framework for declaring, registering, and resetting persistent configuration parameters. It supports versioning, reset templates, and array declarations. This pattern is isolated and could be extracted for any embedded project needing a structured, type-safe configuration store. It demonstrates non-obvious C macro craftsmanship with automatic version tracking and sentinel validation, as verified by unit tests.
DMA resource management with allocation, descriptor tables, and IRQ handler registration. Provides functions like dmaAllocate(), dmaGetChannelSpecByPeripheral(), and dmaSetHandler(). The pattern includes owner tracking to prevent double-allocation and is thoroughly tested via unit tests (dma_reqmap_f7_unittest.cc, dma_bounds_unittest.cc). Reusable for any STM32-based project needing deterministic DMA channel assignment.
A vtable-based abstraction for display outputs, supporting multiple backends (MAX7456, OLED, CRSF, MSP). Defines a displayPortVTable_t struct with function pointers for clearScreen, drawScreen, writeString, etc. This clean interface allows CMS and OSD code to be independent of hardware. The pattern is portable to any embedded system requiring a pluggable display layer.