SFFS138 December 2021 TCAN1164-Q1
Recessive bus state is when the bus is biased to a common mode of about 2.5 V via the high resistance internal input resistors of the receiver of each node on the bus across the termination resistors. Recessive is equivalent to logic high and is typically a differential voltage 0.5 V or less between CANH and CANL. Recessive state is also the idle state.
Dominant bus state is when the bus is driven differentially by one or more drivers. Current is induced to flow through the termination resistors and generate a differential voltage on the bus. Dominant is equivalent to logic low and is a differential voltage on the bus greater than the minimum threshold of 0.9 V for a CAN dominant. A dominant state overwrites the recessive state.
The following sections provide the functional safety mechanisms that cover the CAN communication: