SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
The I2C module generates start (S) and stop (P) conditions when it is configured as a controller.
The bus is considered busy after the S condition (the I2C_IRQSTATUS_RAW [12] BB bit is 1 to indicate that the bus is busy) and free after the P condition (the I2C_IRQSTATUS_RAW [12] BB bit is 0 to indicate that the bus is free).
Figure 12-119 shows the waveforms that occur during an S and a P condition.
I2C controller does not support messages non-compliant with I2C standard. Void messages are non-standard I2C messages and will lockup the controller. A void message is a START condition followed by a STOP condition, in other words, while the bus is free the SDA line is pulled low (START) and then released (STOP). This would result in a timeout (software) of the next controller transfer which would never complete. A soft reset of the controller is recommended for recovery.