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TCAN2451-Q1: TCAN2451-Q1: Wake up by CAN

R Bramlo
Prodigy 10 points

Part Number: TCAN2451-Q1

Hello TI Team:

I would like to have your support  please for part number TCAN2451-Q1.

Once the device is correctly configured to be woken by CAN (WUP) and Local wake-up inputs(LWU) and it's set to be in sleep mode, focussing the wake-up use case just to CAN.

Just to be sure about data sheet described behavior for CAN wake-up source, 

1-The SBC would be woken only by CAN Wake Up Pattern (WUP)
    ¿Could You please comment and confirm?

2-¿Is it supported to configure the SBC to be woken by any CAN bus Activity?

3-¿Is it supported to configure the SBC to be woken by any valid CAN Message?

I would appreciate your answers.

  • 0
    TI__Mastermind 18166 points

    Hello,

    Thanks for reaching out! I will look over this and get back to you tomorrow. 

    Regards,

    Matt 

  • 0 in reply to Matt Smith
    TI__Mastermind 18166 points

    Hello,

     

    If you have the device configured to be woken up by a WUP on the CAN bus (BWRR) and a LWU, then the CAN WUP is not the only way to wake the device up. You would be able to wake the device up by a static wake or cyclic sensing wake via the WAKEx pins, depending on how you have them configured (see section 8.3.12.2). When a WUP or an LWU is received, the CRXD will either be latched low or start pulsing to let the controller it is connected to know it needs to be woken up via SPI write.

     

    In regards to your questions about the SBC being woken up by any CAN bus activity or any valid CAN message, a WUP is defined as a filtered dominant bit, followed by a filtered recessive bit, followed by another filtered dominant bit. To be considered “filtered”, each of these bits needs to have a bit width that is greater than tWK_FILTER(max), which is 0.95us (see section 8.3.12.1). If we convert the bit width to a data rate, that would mean any valid CAN frame at 1.042 Mbps or below would contain a valid WUP for the device since each CAN frame starts with a dominant bit followed by the arbitration field which will contain at least 1 recessive bit followed by a dominant bit.

    Regards,

    Matt