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TCAN1145-Q1: the relationship between Tx-selfACK and wake-up bit

Nguyen Doan
Prodigy 10 points

Part Number: TCAN1145-Q1

Please help me check the influence of the Tx-SelfACK on the operation of wake-up bit (CANINT) on the TCAN1145. 

Scenario:

1, Disable Tx-selfACK on CANoe

CANINT bit set to 1. TCAN1145 status change from sleep to normal.

2, Enable Tx-selfACK on CANoe

CANINT bit is 0, TCAN1145 status change from sleep to normal.

Background: I'm using CAN-NM message to wake up bus from sleep to normal. but I see different behaviour between enable and disable Tx-selfACK. but I don't know why

Please help me check this.

  • 0
    TI__Mastermind 22652 points

    Hi Nguyen,

    Is Selective Wake enabled?

    So for the background of CANINT, this is set to 1 when a valid CAN wake up frame (WUF) is present. The WUF is when Selective Wake is enabled and the transceiver is looking for a particular ID. 

    It is likely that when the ACK bit is enabled, the CAN frame no longer matches the Selective Wake ID program into TCAN1145. This might explain why CANINT is still 0.  

    Best,

    Ethan

  • 0 in reply to Ethan Sempsrott
    Prodigy 10 points

    Hello Ethen

    You mean, If Tx self-ACK is enable, wakeup ID may be changed and WUF is not detected.

    Q1: If device in sleep mode, how many NM_MSG I need to wake up it ?

    Q2: Can I wake up TCAN1145 via TCAN1145's set_mode function without sending the correct WUF signal?

    Thank you

    Doan

  • 0 in reply to Ethan Sempsrott
    Prodigy 10 points

    How I can check Selective Wake ID 

    Can I see it on the can_bus ?

    Best regard

  • 0 in reply to Nguyen Doan
    TI__Guru 68087 points

    Hi Nguyen,

    Today is a public holiday. Please help give some time for some feedback, thanks.

    Best Regards,

    Michael.

  • 0 in reply to Nguyen Doan
    TI__Mastermind 22652 points

    Hi Doan,

    I am not exactly familiar with the CANoe TX Self-ACK functionality so I need your help to properly understand it. My current understanding is that whenever the main MCU sends a CAN frame, it is expecting an ACK from one or multiple other CAN nodes? Does enabling the TX Self-ACK change the CAN arbitration ID?

    Q1: It depends. If Selective Wake (SW) is enabled, then it only will wake to a particular ID (SW ID). If SW is disabled, any valid CAN frame will wake the transceiver. 

    Q2: What do you mean by "set_mode" function? Are you referring to the MODE_SEL register where you can manually switch from Sleep, Standby, Listen, and Normal mode?

    Selective Wake ID: Sections 10.6.27 through Sections 10.6.31 in the datasheet explain the SW ID. You can read these registers with SPI to see what SW ID is being used. Note that you first have to properly setup SW and the SW ID registers. Let me know if you have not done this yet.

    Best,

    Ethan