SWCU195A December 2024 – May 2025 CC2744R7-Q1 , CC2745P10-Q1 , CC2745R10-Q1 , CC2745R7-Q1 , CC2755R10
Data transfers follow the format shown in Figure 25-4. After the Start condition, a target address is transmitted. This address is 7 bits long, followed by an eighth bit, which is a data direction bit (the RS bit in the I2C:CSA register). If the RS bit is clear, the operation is a transmit (send), and if the RS bit is set, the operation is a request for data (receive). A data transfer is always terminated by a Stop condition generated by the controller; however, a controller can initiate communications with another device on the bus by generating a Repeated Start condition and addressing another target without first generating a Stop condition. Various combinations of receive and transmit formats are then possible within a single transfer.
The first 7 bits of the first byte comprise the target address (see Figure 25-5). The eighth bit determines the direction of the message. A 0 in the R/S position of the first byte means that the controller transmits (sends) data to the selected target, and a 1 in this position means that the controller receives data from the target.