• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 83 subscribers
  • Views 411 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.

TMS320F28388D: TMS320F28388D

David Fuertes
Prodigy 55 points
Part Number: TMS320F28388D
Other Parts Discussed in Thread: TMDSCNCD28388D

Dear TI expert,

We want to use the TMS320F28388D with two different configurations: one using both Ethercat links and the other using only one Ethernet link. Both configurations will have different firmware versions.

To save space and components in our board (is a very space coinstraint application), we are thinking about connecting the Ethernet lines to the same PHY module as Ethercat link1, effectively short-circuiting the ENET and ESC1 lines in our board. When working with Ethercat, the Ethernet peripheral would be disabled in the MCU and, when working with Ethernet, the Ethercat peripheral would be disabled in the MCU.

Do you see any inconvenient in short-circuiting the ESC1 and ENET signals and sharing the same PHY module? The PHY module we intend to use is DP83822HFRHBR. In which state do you recommend to configure the disabled pins?

Thank you very much for your answer.

  • 0
    TI__Mastermind 42195 points

    David,

    I would have a small concern about stubs, but for the most part I think it would be fine. You will need to verify, but honestly I suspect you won't have any issues. If possible it may be good to add 0ohm resistors to disconnect the stubs from the unused circuit. Of course if you really only want them to differ by firmware that wouldn't be an option for you design.

    The unused GPIOs should be configured as inputs, this will act as a tristate. 

    I would also recommend that you use an external 25MHz crystal or oscillator to clock the PHY.

    I too briefly considered doing something like this when designing the TMDSCNCD28388D controlCARD, ultimately I decided that too many signals were different and I could support all three with the board space I had. Nonetheless this is an interesting application, and I would love to hear more details about your system if you can share them!

    Regards,
    Cody 

  • 0 in reply to Cody Watkins
    Prodigy 55 points

    Cody,

    Thank you for answer. We will follow your recommendations regarding the resistors and external crystal. About the application, if you want we can discuss it privately.

    Regards,

    David