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TUSB8041A: ? Hub - Multi USB 2.0 --> USB3.x

Nicholas Carley
Genius 9045 points
Part Number: TUSB8041A

Do we have any USB 3.X hubs that will aggregate traffic from multiple USB 2.0 devices downstream, and send it upstream using USB 3.X?

  • 0
    TI__Guru 60870 points

    Hi Nicholas,

    No, TI does not have a hub that can do this and it is pretty far outside the USB specification so that may require a custom solution.

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Genius 9045 points

    HI JMMN,

    Thank you for the clarification. As a follow up on using the a USB hub:

    Since the USB 2.0 subsystem and USB 3.0 subsystem are two separate functional blocks (see image), can a 2 port USB 3.0 Hub support 2x USB2.0 + 2x USB 3.0 devices at the same time? The further specify, do the D+/D- lines and the SuperSpeed lines on the upstream cable operate sequentially or parallel when communicating to the host?

    Thanks,
    Nick

  • 0 in reply to Nicholas Carley
    TI__Guru 60870 points

    Hi Nick,

    Yes, the USB 3.0 and USB 2.0 bus are separate and run concurrently.  You can have 2 USB 3.0 devices connected and 2 USB 2.0 devices connected at the same time.  USB 2.0 devices will not impact the throughput of the USB 3.0 bus and the USB 3.0 devices will not impact the throughput of the USB 2.0 bus.

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Genius 9045 points

    Hi JMMN,

    Thank you! Based on the information above– it seems like I would only need a “two port” USB3.x hub in order to configure for 2x USB 2.0 devices and 1x 3.0 device, is that correct? Are you sure we can split the D+/D- lanes from the SS lanes like this? My thoughts on the 2-port configuration below:

    Do you have a recommendation for a 2-port USB hub?

  • 0 in reply to Nicholas Carley
    TI__Guru 60870 points

    The hub can support simultaneous USB 3.0 and USB 2.0 connections on a single port and does so when connecting tiers of USB 3.x hubs.  Electrically routing a single port to separate USB 3.0 and USB 2.0 devices would work, however, there are some issues.  One is that the port power control is shared between the buses on a single port.  Two is that USB 3.x compliance requires that all USB 3.x device be able to drop to USB 2.0.  Three is that TI cannot guarantee that USB drivers will support this.  The last one is the big issue, the host is not expecting two different devices on the same port of the hub that don't have a matching BOS descriptor and we can't be sure of the operation.

    Regards,

    JMMN