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TCAN1042-Q1: Difference between silent mode and standby mode

Part Number: TCAN1042-Q1
Other Parts Discussed in Thread: TCAN1051,

Hi team,

Could you please help to explain the difference between silent/standby/sleep mode? 

And do we need to wake up the CAN transceiver with WUP/WUF when the transceiver under silient mode? Or when the WUP/WUF is needed?

Thanks

  • Hi Fery,

    The silent mode (as implemented in TCAN1051) holds the transmitter output in the recessive state while keeping the receiver portion fully active. This means that all CAN signaling will pass through to RXD but no signaling from TXD will pass to the bus. In standby mode (as implemented in TCAN1042), both the transmitter and receiver are disabled and a low-power monitor circuit monitors the bus for wake-up patterns. If a wake-up pattern is detected, the RXD signal will go low. At this point the MCU can transition the transceiver into normal mode by deasserting the STB pin.

    Please let me know if this unclear or if you have other questions.

    Regards,
    Max
  • Hi Max,

    I noticed an app note as below, shows the standby mode is listen only, while sleep mode both driver and receiver are shut down, is it correct?

    Also I wondering how the ACK perform in different mode? Will it perform ACK to the BUS while it is in Standby/Sleep/Silent mode?

    Thanks!

  • Hi Fery,

    Yes, that is mostly correct. The bus monitor that is active in standby mode behaves a little differently from the normal receiver, though. It only drives RXD low after detecting a wake-up pattern, and even then will only hold RXD low for dominant bits after they exceed the duration of the wake-up filter (tWK_FILTER). You can get a better understanding of the behavior by referencing Figure 15 in the TCAN1042-Q1 datasheet.

    In both standby and silent modes, the transceivers will not be able to send ACKs. The driver circuit is disables, so the output state cannot be dominant (which is required for ACKs and any other communication).

    Max