SWCU193A April 2023 – August 2024 CC2340R2 , CC2340R5 , CC2340R5-Q1
A controller can start a transfer only if the bus is idle. However in some cases, two or more controllers can generate a Start condition at a similar time. During the transfer, all controllers constantly monitor the SCL and SDA lines. All controllers that detect SDA as low when the controllers expect SDA to be high (as driven by them) acknowledge that another controller has won the arbitration and immediately stop transfers, and retire until the bus is idle again.
Arbitration can occur over several bits. The first stage of arbitration is a comparison of address bits; if both controllers are trying to address the same device, arbitration continues to the comparison of data bits.