Device for a user station of a serial bus system, and method for communicating in a serial bus system

A device of a user station, which is one of a plurality of user stations of a serial bus system, the device comprising:

• circuitry coupled to lines of a bus of the bus system, by which a signal is receivable from the bus of the bus system, the signal being based on a transmission signal via which a message is exchanged between the user stations of the bus system;
• and
• a processor, wherein:
• the processor is configured to:
• in a first communication phase in which, in the signal, a recessive bus state is overwritable by a dominant bus state, interpret the received signal using a first reception threshold;
• in a second communication phase in which bus states other than the recessive and the dominant bus states are present in the signal, interpret the receives signal using a second reception threshold;
• evaluate the signal from the bus of the bus system using a switchover reception threshold that differs from the first reception threshold and the second reception threshold;
• and
• perform a time-limited switchover of the user station from a mode in which the first reception threshold is used to a mode in which the second reception threshold is used in response to detection of presence of a predefined bus level of the transmission signal using the switchover reception threshold;
• and
• for the time-limited switchover of the reception threshold from the first reception threshold to the second reception threshold, switch the user station into an operating mode that differs from three other operating modes of the device, and wherein the three other operating modes of the device include:
• a first operating mode for transmitting and/or receiving the signal in the first communication phase,
• a second operating mode only for receiving the signal in the second communication phase, and
• a third operating mode for transmitting and receiving the signal in the second communication phase.

A user station for a serial bus system, the user station comprising:

• a device for control of communication of the user station with other user stations of the bus system, the device including:
• circuitry coupled to lines of a bus of the bus system, by which a signal is receivable from the bus of the bus system, the signal being based on a transmission signal via which a message is exchanged between the user stations of the bus system;
• and
• a processor, wherein the processor is configured to:
• in a first communication phase in which in the signal different values are provided by a recessive bus state and a dominant bus state, interpret the received signal using a first reception threshold;
• and
• in a second communication phase in which in the signal different values are provided without the recessive bus state, interpret the received signal using a second reception threshold;
• and
• responsive to a connection of the user station to the bus system being initiated after others of the user stations have been communicating via the bus system without recognition by the user station of which of the first and second communication phases is currently active on the bus system:
• begin operation of the user station according to the second communication phase;
• and
• switch operation of the user station from the second communication phase, in which the second reception threshold is used, into the first communication phase, in which the first reception threshold is used, upon detection of a level of the signal being above a third reception threshold for a predefined amount of time, the third reception threshold being different than the first and second thresholds.

A bus system, comprising:

• a bus;
• and
• a plurality of user stations that are connected to one another via the bus in such a way that they may communicate serially with one another, a first one of the user stations including:
• a device for control of communication of the first user station with other user stations of the bus system, the device including:
• circuitry coupled to lines of a bus of the bus system, by which a signal is receivable from the bus of the bus system, the signal being based on a transmission signal via which a message is exchanged between the user stations of the bus system;
• and
• a processor, wherein the processor is configured to:
• in a first communication phase in which in the signal different values are provided by a recessive bus state and a dominant bus state, interpret the received signal using a first reception threshold;
• and
• in a second communication phase in which in the signal different values are provided without the recessive bus state, interpret the received signal using a second reception threshold;
• and
• responsive to a connection of the first user station to the bus system being initiated after others of the user stations have been communicating via the bus system without recognition by the first user station of which of the first and second communication phases is currently active on the bus system:
• begin operation of the first user station according to the second communication phase;
• and
• switch operation of the first user station from the second communication phase, in which the second reception threshold is used, into the first communication phase, in which the first reception threshold is used, upon detection of a level of the signal being above a third reception threshold for a predefined amount of time, the third reception threshold being different than the first and second thresholds.

A method of a user station of a plurality of user stations that communicate in a serial bus system, wherein a signal is receivable by the user station from a bus of the bus system, the signal being based on a transmission signal via which a message is exchanged between user stations of the bus system, and wherein the user station is configured to (a) in a first communication phase in which, in the signal, different values are provided by a recessive bus state and a dominant bus state, interpret the receives signal using a first reception threshold, and (b) in a second communication phase in which, in the signal, different values are provided without the recessive bus state, interpret the received signal using a second reception threshold, the method comprising:

• responsive to a connection of the user station to the bus system being initiated after others of the user stations have been communicating via the bus system without recognition by the user station of which of the first and second communication phases is currently active on the bus system:
• beginning operation of the user station according to the second communication phase;
• and
• switching operation of the user station from the second communication phase, in which the second reception threshold is used, into the first communication phase, in which the first reception threshold is used, upon detection of a level of the signal being above a third reception threshold for a predefined amount of time, the third reception threshold being different than the first and second thresholds.