In addition to Open-Drain, Pull-Up, and High-Keeper, the I3C Bus has three distinct conditions under which the Bus is considered inactive: Bus Free, Bus Available, and Bus Idle.
- Bus Free condition is defined as a period occurring after a STOP and before a START and for a given duration (e.g., tCAS and tBUF timing).
- Bus Available condition is defined as a Bus Free condition with duration of at least tAVAL. A Target may only issue a START request (e.g., for In-Band Interrupt or Controller Handoff) after a Bus Available condition.
- Bus Idle condition is defined to help ensure Bus stability during Hot-Join events. This condition is defined as a period during which the Bus Available condition is sustained continuously for a duration of at least tIDLE.