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Original question:

TUSB8041: USB 3.0 12 port HUB daisy chain vs cascade confuguration

TUSB8043: How to daisy chain USB hubs

Ben Palmer
Prodigy 150 points
Part Number: TUSB8043
Other Parts Discussed in Thread: PCM2903C

I am looking at the TUSB8043 Hub and am wanting to daisy chain them so I can have 12 (or more if possible) on one device. This post here seems to say it is possible:

https://e2e.ti.com/support/interface/f/138/t/660115?TUSB8041-USB-3-0-12-port-HUB-daisy-chain-vs-cascade-confuguration

1) Is there a basic schematic for how this is done? Did Jeremy have any success? What pins are connected between the USB hubs?

2) Jeremy asks if there is a way to identify the ports. Jorge replied that software would have to identify the ports. With the TUSB8043 and the HID, can you give each port a unique name? I am specifically wanting to have 12 USB ports connected to USB Audio Codecs. I then want to name each port a different name for the Codec. Is this possible?

Thank you for your help!

Ben

  • 0
    TI__Guru 60865 points

    Hi Ben,

    1. USB hubs are tiered, not daisy chained.  So you would connect the upstream port of a TUSB8043/A to a USB host (TIER 1), and then each of the downstream ports of the TUSB8043/A hub could then be connected to another hub (TIER 2) and so on.  The USB specification supports up to 5 tiers of hubs in an application.  You definitely need the USB DP/DM lines and USB SS lines (remember to connect TX to RX, not TX-TX/ RX-RX) connected.  Port power control can be implemented or not depending on the application.  USB_VBUS of each hub should only be on when the upstream port is active.

    2. From the hub silicon standpoint, you can't "label" the ports of the hub.  It may be possible to develop a higher level application that names Port x of Hub on Tier Y a certain thing, but we don't have that ability at the device level.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 150 points

    Thank you for the quick response!

    It seemed like this Hub had the ability to have a custom descriptor. Is that just for the hub itself, and not per port descriptions?

    What if I used a Codec with a programmable descriptor, such as the PCM2903C? Could that possibly work?

    Thanks!

  • 0 in reply to Ben Palmer
    TI__Guru 60865 points

    Hi Ben,

    USB hub descriptors are not always loaded by the operating system in a useful way.  For example, the custom hub descriptors are reported but you can't necessarily see them in Device Manager or similar tools without digging deep into the menus and there are no port descriptors.  I'm not sure on the Codec descriptors, you may need to post that on their forum to confirm.

    Regards,

    JMMN