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TCAN1145-Q1: TX pin GND connection to disable TX function in CAN tranceiver

Lenny Lee
Intellectual 1130 points
Part Number: TCAN1145-Q1

Tool/software:

Hi Team,

Disable TX function at TCAN1145-Q1

1. that is ok to GND connection with TX pin with TCAN1145-Q1? or any HW connection option? it doesn't need to send kind of ACK signal as I2C have?

2. change the operation mode to Listen only, that would no any activity on TX block and also CAN bus?

BR.

Lenny Lee.

  • 0
    TI__Guru 53575 points

    Hi Lenny,

    The passive state for a CAN transceiver is a recessive high signal on TXD and RXD. If a node is not required to transmit any data on the CAN bus, the TXD signal may be tied high to ensure it does not impact other communication on the CAN bus. This pin also has an internal pull-up so it would also be acceptable to leave the pin floating. 

    The CAN protocol does expect an ACK to be sent to acknowledge a CAN frame was received, so if this is the only listening node on the bus then it should be able to drive this ACK bit. If there are other nodes on the bus communicating with each other, it will be sufficient for those nodes to generate ACK bits (all active nodes will ACK at the same time). 

    Yes, settin the transceiver into silent mode will disable the CAN driver while the CAN receiver remains active. In this state, any information on the TXD signal will be ignored while RXD will continue to reflect the state of the CAN bus.

    Let me know if you have any more questions.

    Regards,
    Eric Schott