@[Oswin Lin]
Thanks Oswin!
The hardest part wasn't the core math—it was enforcing strict separation between the AI state machine and silicon-specific runtime quirks (interrupts, endianness, and peripheral drivers).
Three rules made true portability possible:
1.Zero Vendor Headers in Core: The core AI triage (ai_health_triage.c) and state machine only use <stdint.h> and <stdbool.h>. Vendor-specific SDKs (ESP-IDF, nRF Connect, STM32Cube) are banned from core logic and restricted strictly to thin adapter files (hardware_adapters/).
2.Byte-Alignment & Packing: Explicit struct packing (#pragma pack(push, 1)) ensures sensor frames and BLE tokens align identically whether running on 32-bit ARM Cortex-M (Nordic/STM32/NXP), Xtensa/RISC-V (ESP32), or 64-bit ARM Linux gateways.
3.Static Memory & Fixed Buffers: By eliminating malloc/free, we avoided platform-dependent heap managers and fragmentations entirely.
The payoff: Porting the entire stack to a new microcontroller target just takes writing a single ~80-line HAL wrapper for the radio/I2C without changing a single line of decision logic.