1.3.3 Bus Conditions
The I3C bus is considered inactive after a Stop when there are no transactions happening on the bus for a certain time duration.
- A Bus Free condition happens after TBUF time following a Stop on the bus, which is specified as 38.4 ns for a pure bus. The controller is allowed to begin a new transaction using a Start after this time. The BFREE bit is set in the I3C module when a Stop is detected on the bus, and the bit clears when a Start is detected.
- A Bus Available condition happens when a Bus Free condition is sustained for TAVAL time, which is specified as 1 µs for a pure bus. The Target is allowed to request an In-Band Interrupt after this time. This time must be configured using the I3CxBAVL register for proper operation.
- A Bus Idle condition happens when a Bus Free condition is sustained for TIDLE time, which is specified as 200 µs for a pure bus. The Target is allowed to request a Hot-Join after this time. This time must be configured using the I3CxBIDL register for proper operation.
- In addition, when there is no activity on the SCL line after a Start is detected
(BFREE =
0), then an additional Bus Time-out timer can be configured using the I3CxBTO register to notify the Target of a stalled bus through the BTOIF bit. The feature can be enabled using the BTOEN bit.