• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 34 subscribers
  • Views 249 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCAN4550: MCU wake: pros and cons of using nWKRQ vs nINT

Ole Kristian Western
Prodigy 85 points
Part Number: TCAN4550

What are the pros and cons of using nWKRQ vs nINT for waking the host MCU. We will implement the ISO 11898-2:2016 WUP. I see the timing nWKRQ vs nINT is a bit different in the wake event, which doesn't matter to us. We already have nINT connected, but host MCU pins are scarce so we would like to avoid nWKRQ unless needed. The nINT host MCU interrupt routine will change dependent on the mode/state it's in. Are there some scenarios where nWKRQ could prove beneficial or absolutely necessary?

  • +1
    TI__Guru 53555 points

    Hi Ole,

    The nWKRQ pin is a dedicated wake up request output that can serve a few different purposes. Some of the primary differences between this and the nINT pin is that this pin is controlled only by the wake request interrupt bits, so it may be used to control a an external voltage regulator for instance if the Vsup level of the INH pin cannot be used. Another unique aspect of this pin is that it can be supplied by an internal supply rail so it can be active when Vio is not available. For comparison, the nINT pin will only be driven when the Vio logic supply is active. 

    For the application you describe, it does not seem like either of these use cases are necessary and the nINT signal will be sufficient to notify the MCU of any wake condition. So I agree that the MCU pin can be saved by leaving nWKRQ floating for this application. 

    Let me know if you have any more questions. 

    Regards, 
    Eric Schott