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TUSB2046B: Power on downstream, it sometimes goes to suspend mode

V.Sanz
Prodigy 50 points
Part Number: TUSB2046B

Hi,

i have some issues with TUSB2046BVFR. Its working with 2 downstream ports, perfectly, without problems. The hub enumerates fine on both PCs (windows 7 laptop & windows 10) and i can comunicate with both downstream devices. 

Both downstream devices can be powered on and down. When i power down them (both share  a LM7805) and i power on again, usually it works fine, but, sometimes, the TUSB2046 goes to SUSPND mode.

I dont understand why sometimes it works perfectly and, the next power on (i just switch on/off to test), it doesn't work, i switch it again, and it works again. Why so much fluctuations???

Thanks,

Victor

  • 0
    TI__Mastermind 18655 points
    Hello V.Sanz,

    The DP and DM signals of the downstream ports should be tied to ground with 15K resistors.
    All the OVRCUR/ inputs should have a pull-up resistor.

    Do you have unused ports?
    The DP and DM signals of the unused port should be tied to ground with 15K resistors like the pull-downs used on the active ports.

    Regards
  • 0 in reply to Joel Jimenez0
    Prodigy 50 points
    Hello Joel,

    I have all the DP and DM signals of the downstream ports tied to ground via 15k resistors. (sorry, i forget paste the input part of sch).

    All the OVRCUR are connected together (ganged mode) with a 15k pull-up resistor.

    On upstream i have DP with a 1k5 pull-up. Should i also have a 1k5 pull-up on upstream DM? And both (DP and DM) tied to ground with another 15k resistors?

    Regards
  • 0 in reply to Joel Jimenez0
    Prodigy 50 points
    i have all the pull-up resistors and downstream ports tied to ground
  • 0 in reply to V.Sanz
    TI__Mastermind 18655 points
    Hello V.Sanz.

    Have you tried to reproduce the same behavior but connecting the downstream devices directly to the USB host? Does the issue happen with other USB devices?
    Can you send me the complete schematics in a private massage?

    Regards
  • 0
    Prodigy 50 points

    Last test i did, with this exactly sch

    It has same issues

    Both devices attached to the hub. every one have a different VID/PID

    Now i turn off 1 device

    if i turn on it again, SOMETIMES works ok, sometimes it happens:

    its always the 2 same devices. i just connected one switch in the power of each device.

  • 0 in reply to Joel Jimenez0
    Prodigy 50 points

    Hello Joel

    Yes. With the devices directly to the USB host, when i turn off/on them, they work perfetly 100% of time. the issues only happens with my HUB.

    The exactly schematic is pasted in my last reply

  • 0 in reply to V.Sanz
    TI__Mastermind 18655 points
    Hello V.Sanz,
    Please, load usbview.exe (it is a debug application available for free from Microsoft). Install the utility, select the Unknown Device in the left hand window, select the Options > Config Descriptor, and then Options -> Auto refresh and then hit F5. You should be able to see most descriptors reported by the hub in the right hand window. Please, send captures of these descriptors.
    Regards,
    Joel