Full hardware UART driver with config-driven per-instance setup.
Non-blocking SendBuffer supports DMA (zero-CPU) and ISR (FIFO-fill)
modes selectable per instance in MCU_UART_cfg.h. Both modes and
blocking SendBufferBlocking invoke a configurable TX-complete
callback (STD_NULL to ignore). All public functions take a u8
instance parameter. Config uses struct-of-arrays pattern for
runtime state, designated-initializer array for per-instance
settings, and value enums in the public header for parity/data
bits/stop bits/async mode. Added hardware_dma to CMake link list.
Dockerized build system (Dockerfile, docker-compose, build.sh) with
Pico SDK cross-compilation. Modular CMake split into project_config,
mcu_config, and sources_config under cmake/. Component architecture
following inc/prg/cfg convention: STD_TYPES, MCU_USB, HAL_COM,
APP_CLSW, SYS_ECU. Full call chain SYS_ECU -> APP_CLSW -> HAL_COM
-> MCU_USB verified end-to-end on RP2040-Zero hardware over USB-CDC.
Includes flash.sh for automated .uf2 flashing on macOS and
devcontainer config for VS Code.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
