SWCU192 November 2021 CC1312R7 , CC1352P7 , CC2652P7 , CC2652R7
A master may start a transfer only if the bus is idle. Two or more masters can generate a Start condition within minimum hold time of the Start condition. In these situations, an arbitration scheme occurs on the SDA line, while SCL is high. During arbitration, the first of the competing master devices to place 1 (high) on SDA while another master transmits 0 (low) switches off its data output stage, and retires 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 masters are trying to address the same device, arbitration continues to the comparison of data bits.