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SN65HVD1040: standby

Part Number: SN65HVD1040

hi,

my customer T... need some help regarding the wake up feature.

In my current project (consisting of several battery-driven modules), I would like to enable the system or the modules via CAN bus, so I selected the TI CAN transceiver (SD65HVD1040). In this regard I have the following questions, which are unclear to me and ask you or your CAN Expert colleagues for clarification:


- According to the datasheet, a dominant bit is longer than 5 us on the CAN bus,

can a CAN subscriber from the standby mode be awakened by the fact that this dominant bit is perceived by the receiving part of the CAN transceiver, and the transceiver can wake up.

My question is: all stations which are on the CAN bus in standby mode will wake up?

 


- Two CAN subscribers communicate with each other, and another subscriber is in the standby mode, which happens when a dominant bit (or a sequence thereof) occurs through this communication, in total is longer than 5 μs, this means that the CAN subscriber , Which is in the standby mode, in this case will awakened also?
- Please provide a brief description of all possible scenarios

 

regards,

kamal

  • Hi Kamal,

    Yes, any time the transceiver detects a dominant state on the CAN bus that persists for longer than the tBUS parameter (whose maximum value is 5 us), its RXD output will go low (until the bus returns to the recessive state). This signals to the CAN controller on the receiving node that there is CAN bus activity and it should wake up by de-asserting the transciever's standby control pin. Since all nodes will share the same bus lines, a long-enough dominant pulse will trigger an indication to wake up in all nodes. If a node is in standby while other nodes communicate, that node will also be triggered to wake-up as long as it receives a dominant pulse with duration longer than tBUS.

    I hope this is all clear, and please let me know if you have any other questions.

    Best regards,
    Max