Communication system having a can bus and a method for operating such a communication system

A communication system, comprising:

• a CAN bus;
• at least two devices interconnected via the CAN bus, at least one of the devices including:
• a CAN controller adapted to CAN data frames over the CAN bus using a first physical protocol in a first operating mode;
• an asynchronous serial communication interface unit adapted to transmit ASC data frames over the CAN bus using a second physical protocol in a second operating mode;
• a first switch adapted to switch between the first operating mode and the second operating mode, as a function of at least one agreement in effect between the device and at least one other device;
• and
• a second switch adapted to switch the device to a third operating mode, which is different from the first operating mode and the second operating mode, for powering up the device;
• wherein the device, in the third operating mode, is adapted to transmit a CAN reference message over the CAN bus if it has not received any reference message from other devices connected to the CAN bus within one communication cycle of the CAN bus.

A communication system, comprising:

• a CAN bus;
• at least two devices interconnected via the CAN bus, at least one of the devices including:
• a CAN controller adapted to CAN data frames over the CAN bus using a first physical protocol in a first operating mode;
• an asynchronous serial communication interface unit adapted to transmit ASC data frames over the CAN bus using a second physical protocol in a second operating mode;
• a first switch adapted to switch between the first operating mode and the second operating mode, as a function of at least one agreement in effect between the device and at least one other device;
• and
• a second switch adapted to switch the device to a third operating mode, which is different from the first operating mode and the second operating mode, for powering up the device;
• wherein the second switch is adapted to switch the device to the third operating mode via a special configuration bit.

A method for operating a communication system having a CAN bus and at least two devices interlinked via the CAN bus, the method comprising:

• switching at least one of the devices between different operating modes;
• transmitting, by a CAN controller of one of the devices, CAN data frames over the CAN bus in a first operating mode using a first physical protocol;
• transmitting by an asynchronous serial communication interface unit of the device ASC data frames over the CAN bus using a second physical protocol in a second operating mode;
• and
• switching the device to a third operating mode, which is different from the first operating mode and the second operating mode, for powering up the device, wherein in the third operating mode the device is prevented from participating in ASC-based communication over the CAN bus.