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TUSB2046B: USB Hub does not get recognised

Julian Koeck
Prodigy 10 points
Part Number: TUSB2046B
Other Parts Discussed in Thread: TUSB2036,

Hey everyone!

We are developing a four port USB Hub with the TUSB2046 IC. Our schematic is attached. Additionaly, a 1,5k Pullup Resistor is connected between "USB_UP_D_P" and "VDD_3V3".

The Upstream Port is connected to our SOM running Android 11, Linux kernel 5.10.72.

The Hub does not get recognised. No entrys in the debug log, no entry after running the "lsusb" command.

When swapping the TUSB2046 IC for a TUSB2036 IC and modifying the PCB slightly (tying pins 21 - 24 to ground), the TUSB2036 hub does get recognised instantly and all three ports work like a charm. The 6MHz signal is present on both boards.

Why is the four port hub not working but the three port one is?TUSB2046_Hub.pdf

TUSB2046_Hub.pdf

  • 0
    Prodigy 10 points

    I have tried to evaluate the error further and got following excerpt from the bootlog when using the TUSB2046 IC.

    [   84.583372][  T212] usb 2-1.4: new full-speed USB device number 4 using ci_hdrc
[   84.671379][  T212] usb 2-1.4: device no response, device descriptor read/64, error -32
[   84.867013][  T212] usb 2-1.4: device no response, device descriptor read/64, error -32
[   85.062995][  T212] usb 2-1.4: new full-speed USB device number 5 using ci_hdrc
[   85.146993][  T212] usb 2-1.4: device no response, device descriptor read/64, error -32
[   85.347052][  T212] usb 2-1.4: device no response, device descriptor read/64, error -32
[   85.464025][  T212] usb 2-1-port4: attempt power cycle
[   86.075438][  T212] usb 2-1.4: new full-speed USB device number 6 using ci_hdrc
[   86.499090][  T212] usb 2-1.4: device not accepting address 6, error -32
[   86.583011][  T212] usb 2-1.4: new full-speed USB device number 7 using ci_hdrc
[   87.003011][  T212] usb 2-1.4: device not accepting address 7, error -32
[   87.009939][  T212] usb 2-1-port4: unable to enumerate USB device

  • 0 in reply to Julian Koeck
    TI__Guru 60870 points

    Can you confirm that the thermal pad of the TUSB2046B has a good connection to ground and confirm the reset timing?

    I don't see anything incorrect in the schematic.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 10 points

    Hi JMMN,

    Thanks for your kind reply.

    As we are using the QFP package of the TUSB2046, there is no thermal pad. The two ground pins on the other hand are properly conencted to ground.

    Reset timing can be confirmed as far as a reset was tried, when the board was already up for a few seconds and the reset pin was tied to ground for a few seconds and then released.

    So your assumption would be that our board is faulty and we shall try another board?

    Regards,

    Julian

  • 0 in reply to Julian Koeck
    TI__Guru 60870 points

    Hi Julian,

    I don't see anything in the schematic that would prevent it from working.  Can you check if the upstream DP/DM lines toggle at all?

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 10 points

    Hi JMMN,

    Yes the upstream data lines are toggled, otherwise the log in my original post would not be presented.

    Regards,

    Julian

  • 0 in reply to Julian Koeck
    TI__Guru 60870 points

    Hi Julian,

    Actually, the host just needs to see the pullup on DP to start reporting a full speed device as connected.  I was wondering if the host was sending resets and SOFs or not or if the SUSPEND pin went high.

    Regards,

    JMMN

  • +1 in reply to JMMN
    Prodigy 10 points

    Hi JMMN,

    I assembled a fresh PCB yesterday and the hub now works without any problems. So it really just was a soldering issue.

    Regards,

    Julian