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TCAN1463-Q1: WAKEUP and SLEEP Mode

SUHYUN YOON
Prodigy 41 points
Part Number: TCAN1463-Q1
Other Parts Discussed in Thread: AWR1843AOP, , TCAN1146-Q1

Hello, I am a beginner using TCAN1463-Q1 and awr1843aop.

In my application, when the radar sensor receives power, it sets the nSTB and EN pins to high.

The issue is that when any CAN message is received from the CAN bus, the radar sensor transitions to normal mode.

Therefore, I am checking the message ID upon reception and trying to switch back to sleep mode.

However, when continuously sending messages through PCAN with intervals less than 93ms, the radar sensor does not transition to sleep mode and remains in normal mode.

Simultaneously, there are errors in both the transmission and reception of messages.

Based on my assumption, The BUCK Converter is controlled by the INH pin, and since the INH pin is continuously toggling between on and off states,

the 5V voltage supplied to VCC appears to be fluctuating but not dropping below 4.5V(minimum operating conditions).

I would appreciate it if you could confirm whether this speculation is correct, and kindly provide information on any other possible causes.

Thank you very much.

  • 0
    TI__Guru 68742 points

    Suhyun,

    If CAN communication is occurring while the device is trying to go to Sleep mode, this will trigger a CAN bus wake up and keep the device out of Sleep mode and in Standby mode. Once in Standby mode the device will then transition back to Normal mode based on the EN and nSTB pin states. Your assessment of the INH pin going high and low due to the device going into Sleep mode then immediate waking up makes sense, and though the VCC voltage isn't dropping below 4.5V, the CAN bus is still referenced to this voltage. So the fluctuation of the VCC voltage will directly affect the CAN bus waveforms, and this may be what is causing communication issues. 

    Do you have the ability to probe the CANH and CANL waveforms, along with INH, so we can see what may be happening?

    Regards,

    Eric Hackett 

  • 0 in reply to Eric Hackett
    Prodigy 41 points

    Thank you for answer me.

     My approach to the root cause analysis seems to be on the right track.But i am not good at using osilloscope so i need more time figure out INH and VCC state.

    If i would use the TCAN1146-Q1, it appears that, unlike the TCAN1464-Q1, it can wake up through the WUF identification.

    What are you think about to change IC?

  • 0 in reply to SUHYUN YOON
    TI__Guru 68742 points

    Suhyun,

    The TCAN1146-Q1 indeed has WUF validation, but it requires SPI to configure and function, so it will be a significantly different operation. I think it's fine to switch ICs, especially if one node needs to be asleep while others are still communicating on the bus, this is exactly why the TCAN114x-Q1 were designed. 

    If you go to the product folder on TI.com for the TCAN1146-Q1, there is plenty of collateral to help use the TCAN1146-Q1 device for selective wake WUF validation.

    Regards,

    Eric Hackett