Concurrent Multi-Tasking Using Metamorphic SW Replacement

Non-OS Embedded MCU systems are used in diverse environments, with increasing demand for architectures that allow flexible function expansion or switching during operation. Conventional firmware updates typically require system interruption or restart, and while RAM-based approaches have been explored, they still follow a monolithic structure that overwrites a single function. This paper proposes a dynamic architecture that receives and stores function-level binaries in RAM, maintaining multiple functions in parallel and enabling selective switching at runtime. The system incorporates UART communication, DMA-based reception, position-based execution points, and a mechanism for managing and executing candidate functions. Experiments on an STM32F4 board verified functional correctness and showed excellent stability and efficiency with 64-byte slices at 460,800 bps. Unlike traditional methods, the proposed structure enables flexible maintenance and switching of multiple functions, providing a foundation for applying Metamorphic Software Replacement to MCU systems and enabling logical multitasking.