• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 348 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.

TUSB8040A eval board for USB Full Speed 1.1

Matthew Bobowski
Prodigy 20 points
Other Parts Discussed in Thread: TUSB8040A

We purchased two TUSB8040A evaluation boards purely for Microsoft WHQL testing.  For the USB topology test, I need to set one of the boards into full speed operation per USB 1.1.  I've read over the User's Guide, but don't seem to find it.  According to the documentation:  "In general, the speed of the upstream connection of the TUSB8040AEVM limits the downstream connections to that speed (SS, HS, and FS) or lower."  OK, that would get me SS (3.0) and HS (2.0) from my test system's controller ports.  How can I tell the board that it needs to drop down to full speed (1.1)?

  • 0
    TI__Guru 60865 points

    Hi Matthew,

    USB Hubs are slave devices, they automatically connect at the speed of the upstream connection.  There is no way to force them to full speed unless you put a full speed hub in the path between the host controller and the TUSB8040A.  Typically, keyboards or keypads with exposed USB ports incorporate full speed USB hubs.

    Regards,

    J Nirchi

  • 0 in reply to JMMN
    Prodigy 20 points

    That answers my question.  However, it would be really nice if an evaluation board could downgrade the USB from 3 -> 2 -> 1.x with a DIP switch.  I understand your explanation, and it does further the documentation.  However, from a different viewpoint, it is slightly misleading in the product overview (the eval hub board is SS, HS, FS, LS capable yes, but not overridable).  And, it is virtually impossible to buy a USB 1.x hub unless TI offers one, or you know of one still available.  Yes, the older keyboards do seem to provide the USB 1.x interface if they have an internal hub and expose an external port.  Thanks again, and you know I'm just trying to get through the Microsoft Windows driver certification (WHQL).

  • 0 in reply to Matthew Bobowski
    TI__Guru 60865 points

    Admittedly, speed select would be a nice test feature, however, USB spec requires that devices connect at the highest speed possible that they claim to support in their USB descriptors. The only exception is USB 3.0 hubs like the TUSB8040A that connect at both SS and HS when possible.

    TI does sell FS hubs (TUSB20xx devices), but since you are really only interested in WHQL testing it would be a lot more cost effective to buy a Targus Keypad.  They incorporate FS hubs and they are used at a lot of the USB test houses for this purpose.  You can find them online for under $20.

  • 0
    Guru 243980 points

    Check the Device Manager on your host PC. If you have UHCI ("Universal") or OHCI ("Open") USB Host Controllers (all chipsets except recent Intel ones do), then you can disable or uninstall the EHCI ("Enhanced") controller(s) to force that port(s) to full speed.