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DM3730 USB PORTSC_i->PED field

RY9983
Guru 10570 points
Other Parts Discussed in Thread: DM3730


Hello.
I have a confirmation about operation of PORTSC_i->PED field.
There is description that PED field can not be enable a port by writing to this field in TRM. (sprugn4r: P3370)

My question is:
  - Can I enable this field manually by host? and how can I enable it?
   (some of usb transaction can enable it?)

Best regards, RY

  • 0
    TI__Guru 65405 points

    Hi RY,

    As it is written in the TRM (sprugn4r: page 3370) the software cannot enable a port by writing a 1 to this field. The host controller only sets this to 1 when the reset sequence determines that the attached device is a high-speed device but the ports can be disabled by either a fault condition (disconnect event or other fault condition) or by host software.

    Therefore you cannot enable the PED field manually.

    BR

    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    Guru 10570 points

    Tsvetolin-san,
    I am sorry for my late reply.
    Thank you so much for your answer.

    But, my query is not cleared yet. May I have once more question?

    a) DM3730 USB controller needs external USB PHY.
    When PED field is enabled, USB controller actually reads PHY register to detect if high-speed device is attached.
    Is my considering right?

    b) Can you disclose the USB IP core vendor of DM3730 ?
    I would like to search more detail.

    Best regards, RY

  • 0 in reply to RY9983
    Guru 10570 points

    Tsvetolin-san,
    Thank you for your support.

    Just confirmation.
    You do NOT have any informations about previous my question ??

    Best regards, RY

  • 0 in reply to RY9983
    Guru 10570 points

    Tsvetolin-san,
    Just I am interested in whether I can expect some informations or not.
    What do you think?
    Best regards, RY

  • 0 in reply to RY9983
    TI__Guru 65405 points

    Hi RY,

    Sorry for the delay. About your questions:

    a) Yes, low speed device is detected by its D- pull up initially and full/high speed is
    detected by pull up on D+. Hish speed device is distinguished from full speed device by the high speed
    chrisps on device reset.
    This is done by the PHY and read by the host via the ULPI.

    b) This information is confidential under NDA.

    BR

    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    Guru 10570 points

    Tsvetolin-san,

    Thanks for your information!!

    Best regards, RY