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 for at least tAVAL duration. A Slave may only issue a START request (e.g., for In-Band Interrupt or Master 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.