• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 360 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.

Original question:

TPS23881: Perpetual POE and Fast PoE

TPS23881: Perpetual POE

Lisa Xu
Intellectual 505 points
Part Number: TPS23881

Hi TI Team:

We now use MCU_MSP430F5234IRGZR + PSE Controller_TPS23881A for our POE solution.

Now in our SCH, The Reset signal of TPS23881A connects to MCU_MSP430F5234IRGZR,

and The reset signal of MCU_MSP430F5234IRGZR connects to host,

To do Perpetual POE correctly, we plan to cut the reset signal to avoid interrupt.

What reset signal do you suggest to cut,   MCU to TPS23881A  or Host to MCU?

Best Regards

Lisa

  • 0
    TI__Intellectual 1520 points

    Hi Lisa,

    For perpetual POE to work properly the MCU must not be reset, so it is important to not allow the host to reset the MCU.

    How do you plan on cutting the reset signal? 

    Best Regards,

    Nate Inkster

  • 0 in reply to Nate Inkster
    Intellectual 505 points

    Hi Nate:

    OK,We plan to just disconnect the reset signal from Host to POE MCU,

    In other words, the POE MCU has no external reset signal, POE MCU may restart just by internal watchdog when POE MCU works abnormal.

    Do you have other highlight or consideration when we disconnect the reset signal from host to POE MCU?

    Best Regards

    Lisa

  • +1 in reply to Lisa Xu
    TI__Intellectual 1520 points

    Hi Lisa,

    As you say, if the reset signal is disconnected from the MCU then the ability to perform external reset on MSU is lost, losing the ability to use BSL and JTAG. It would be better to insure that the CPU does not reset the MCU when the CPU powers on and off so that you do not entirely lose the option to externally reset the MCU if needed. The reset pin is active low, so a pull up resistor could be added to keep it high. 

    Best Regards,

    Nate Inkster

  • 0 in reply to Nate Inkster
    Intellectual 505 points

    Hi Nate:

    We will add pull up resistor on the reset pin.

    For BSL and JTAG, We reserved the JTAG Connector for POE MCU. 

    Best Regards

    Lisa