• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 97 subscribers
  • Views 501 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.

USB0_ID pin handling have been changed to floating on OMAPL138.

RY9983
Guru 10570 points
Other Parts Discussed in Thread: OMAPL138

Hello,

I am using OMAPL138 USB0 as device only mode.
When I was designed target board, the user guide(SPRUfm9d) had been described that USB0_ID should pull-up to DVDD33 rail with an external 10K ohm resistor.
But, I have noticed the description is changed in current TRM(SPRUh77a).

SPRUh77a
(P1593) 35.2.2 Signal Descriptions
USB0_ID : For OTG mode or device only mode of operation, do NOT connect the USB0_ID pin, that is, leave the pin floating.

Since I have already produced equipments, could you give me some advices?

 - We must change USB0_ID pin as floating?
  (Now, our equipment have been operate properly.)

 - Can you disclose why the handling has been changed?

Best regards,
RY

  • 0
    TI__Guru* 84075 points

    Hi RY

    The USB_ID  pin is a passive analog signal that should not be connected an external source.  The PHY sources current out of this pin and monitors the voltage to make a resistance measurement.

    We regret that this was previously documented incorrectly in the USB guide. Based on design inputs, it is ok to leave your current design as is , with the pull up. However for any new board design , we strongly recommend that you follow the updated guidelines.

    Regards

    Mukul

  • 0 in reply to Mukul Bhatnagar
    Guru 10570 points

    Hello, Mukul.

    Thank you so much for your answer.
    It is helpful for me very much.

    Best regards,
    RY