38.2.5.1 Listen Only Mode

Listen Only mode is a variant of Normal CAN FD Operation mode. If the Listen Only mode is activated, the module on the CAN bus is passive. It will receive messages, but it will not transmit any bits. TXREQx bits will be ignored. No error flags or Acknowledge signals are sent. The error counters are deactivated in this state. The Listen Only mode can be used for detecting the baud rate on the CAN bus. It is necessary that there are at least two further nodes that communicate with each other. The baud rate can be detected empirically by testing different values until a message is received successfully. This mode is also useful for monitoring the CAN bus without influencing it.