SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
If two or more master transmitters start a transmission on the same bus almost simultaneously, an arbitration procedure is invoked. The arbitration procedure uses the data presented on the serial bus by the competing transmitters. When a transmitter senses that a high signal it has presented on the bus has been overruled by a low signal, it switches to the slave receiver mode, sets the arbitration lost (AL) flag, and generates the arbitration lost interrupt. Figure 26-9 shows the arbitration procedure between two devices. The arbitration procedure gives priority to the device that transmits the serial data stream with the lowest binary value. If two or more devices send identical first bytes, arbitration continues on the subsequent bytes.