• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 32 subscribers
  • Views 168 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TUSB4020BI-Q1: Over-riding the downstream power control outputs

Chris Brawn
Prodigy 120 points
Part Number: TUSB4020BI-Q1

A device attached to one of our TUSB4020BI-Q1 downstream ports needs to have it's power cycled occasionally.

Is it possible to do this via the TUSB4020BI-Q1 or would we need to add extra logic to the PWRCTL1 signal? (I couldn't see anything in the datasheet about what turns the PWRCTL1 on or off.)

  • 0
    TI__Guru** 122320 points

    you can turn downstream ports on and off with register 08h though host controller

    Regards

    Brian

  • 0 in reply to Brian Zhou
    Prodigy 120 points

    Thanks for that Brian. My datasheet just says "Reserved. Read only." for register 08h.  Any idea where I can find out more please?

  • 0 in reply to Chris Brawn
    TI__Guru** 122320 points

    ok, It looks USB3 and USb2 are different, let me check.

    Regards

    Brian

  • +1 in reply to Brian Zhou
    TI__Guru** 122320 points

    The Device Removable Configuration register at 07h has the customRmbl bit 7 which must be set to overwrite the default TUSB804x values of the removable ports, used ports and USB 2.0 only ports. Bits 3:0 of register 07h set whether a downstream port is defined as removable (devices can be removed from the port) or non-removable (device is permanently connected to the port). This register defaults to 0Fh. The Port Used Register at 08h sets which ports are enabled or disabled. All combinations are supported with the exception of both ports 1 and 3 marked as disabled. This field is read only unless the customRmbl bit in register 07h is set to 1. When the corresponding USB2_ONLY bit is set, the USB2 port will be used and enabled regardless of the bit programmed into this field. This register defaults to 0Fh.