Case M4: Arbitration Lost or Bus Error
If the arbitration is lost, both the WIF
and the Arbitration Lost (ARBLOST) flags in the Host Status (TWIn.MSTATUS) register are set
to ‘1’. The SDA is disabled, and the SCL is released. The bus state
changes to Busy, and the host is no longer allowed to perform any operation on the bus
until the bus state is changed back to Idle.
A bus error will behave similarly to the
arbitration lost condition. In this case, the Bus Error (BUSERR) flag in the Host Status
(TWIn.MSTATUS) register is set to ‘1’, in addition to the WIF and ARBLOST
flags.
The software can prepare to:
- Abort the operation and wait until the bus state changes to Idle by reading the Bus State (BUSSTATE) bit field in the Host Status (TWIn.MSTATUS) register