EFBus V09 expands typed services and shared embedded infrastructure

The V09 operational reference candidate retains the Wire 2.5 / SDK 0.12.0 compatibility boundary while adding command-authority hardening, multi-endpoint identity, Optional Services, a shared I2C Fabric Manager and multi-target Display support.

What changed in the shared embedded interface?

EFBus is designed as a typed boundary between MCU-controlled devices and higher-level processing. The V09 candidate extends the interface without making unrelated capabilities part of a single mandatory transport: command authority, endpoint identity, optional services and reusable embedded components are treated as separate concerns. Shared I2C management and display-related services can then evolve without confusing application convenience with low-level safety responsibilities.

This is a versioned engineering milestone, not proof that every supported target or external hardware configuration has been qualified. TheArduino EFBus projectexplains the architectural context and distinguishes implementation scope from measured results.