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Does TUSB8040 supports super speed only?

Pan Hu1
Prodigy 40 points
Other Parts Discussed in Thread: TUSB8040

Hi,

I made a TUSB8040 board and routed the super speed signal pins only (both the upstream and downstream links).

Now the board could not be recognized by the computer, and the "SS" and "HS_SUSPENDED" LEDs were lit.

Do I have to route both the super speed and high speed pins? Any help is appreciated.

Thanks,

Pan

  • 0
    TI__Guru* 76130 points

    Hello,

    Your host is probably requesting something through USB2, can you share your schematics for review?

    Regards.

  • 0 in reply to Elias Villegas M.
    Prodigy 40 points

    Hi Elias,

    Thank you for your help.  Please see the attachment for my schematic.

    However, I think it does not make sense the host requires something via USB 2.0. Also, it is not mentioned in the datasheet. 

    I have tried with a PCIE to USB 3.0 adapter using ASM1042 and a  USB3 hub using VLI811. But none of the worked.

    //Edited 3/1/2013

    -Pan

  • 0 in reply to Pan Hu1
    TI__Guru 60870 points

    Hi Pan,

    It is a USB 3.0 requirement that USB 3.0 hubs run at both USB 3.0 and USB 2.0 speed concurrently.  Please note that only the TX pairs require the 0.1 uF caps, they should not be installed on the RX pairs.

    Regards,

    Julie

  • 0 in reply to JMMN
    Prodigy 40 points

    Hi JMMN,

    Thank you. Seems that I have to connect the USB 2.0 signal with flying wires. I will update the experiment results later.

    I understand that only TX pairs requires the 0.1uF caps but I also added 0.1uF caps on the RX pairs to improve the compatibility.  Actually I soldered  0R resistors on the RX pairs. :)

    Thanks,

    -Pan

  • 0 in reply to Pan Hu1
    Prodigy 40 points

    Hi Julie and Elias,

    Thank you for your help. Now it is working!

    According to my test, USB2.0 is needed in TUSB8040, both for the upstream and downstream links.

    -Pan