SWCU193A April 2023 – August 2024 CC2340R2 , CC2340R5 , CC2340R5-Q1
The I2C bus uses only two signals: SDA and SCL. SDA is the bidirectional serial data line and SCL line is the bidirectional serial clock line. The bus is considered idle when both lines are high.
Every transaction on the I2C bus is 9 bits long, consisting of 8 data bits and 1 acknowledge bit. A transfer is defined as the time between a valid start and stop condition, see Section 21.3.1.1. The number of bytes per transfer is unrestricted, an acknowledge bit must follow each byte, and data must be transferred by the MSB first. When a receiver cannot receive another complete byte, the receiver can hold the clock line SCL low and force the transmitter into a wait state. The data transfer continues when the receiver releases the clock SCL.