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TCAN1145-Q1: WUF is not working

Sivakumar Ganesan
Prodigy 30 points
Part Number: TCAN1145-Q1

Hello Ti,

      I am using TCAN1145Q1 and facing some issues in Wakeup by CANID.

i have initialized the Transceiver with the help of Demo code found in TI community page(TCAN114x_Demo).

In my schematic i can see "Wake" pin is always connected with +5V, but i am not using LWU.

If i try to use WUF with 0x144 CANID, wake up is working for all CAN Id's not only for 0x144.

Is this the expected behavior, if connect WAKE pin in +5V always ?

  • 0
    TI__Guru 53555 points

    Hi Sivakumar,

    Thanks for bringing your question to E2E. 

    The WAKE terminal for TCAN1145 is edge sensitive, meaning that any transition from high-to-low or low-to-high will be recognized as a local wake event. A static high state or low state such as being tied to 5V will not cause the device to wake up. The EVM for this device for example has the WAKE pin pulled-up to Vsup and a high-to-low transition can be triggered via the pushbutton, pulling the WAKE pin to ground. 

    In order to configure the TCAN1145 for selective wake ensure that all of the steps in datasheet section 10.4.5.2 are followed. If the device recognizes that selective wake has not been properly configured (such as if SW_EN is set but SWCFG is not), the device will continue to operate in WUP mode and wake to any CAN activity. 

    I'm not familiar with a publically available demo for this device, but you may have a copy of the drivers that have been distributed to select customers. All partial networking configuration options are written using the TCAN114x_PN_Config_Write() function. This function will set all parameters for the wake up frame and set SWCFG to lock the configuration. The software will then have to set the SW_EN bit in the mode control register at the same time as the transceiver is set to sleep mode (these can be done in the same register write as they are both in the mode control register). Once these steps are complete, the transceiver will be able to ignore any CAN from that does not contain the ID and data (if configured) in the wake up frame. 

    Note that the transceiver will still wake from sleep mode due to frame overflow conditions where enough CAN errors are recognized to trigger the failsafe wake up. Ensure that the transceiver is configured to ignore CAN FD frames (SWFDPassive = 1) of these are expected during sleep mode and that the configured data rate for the transceiver is the same as that used on the CAN bus. 

    Let me know if you have any more questions. 

    Regards, 
    Eric Schott