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TUSB4041I: USB Hub not detected by host

Arun Ashok8
Prodigy 85 points
Part Number: TUSB4041I
Other Parts Discussed in Thread: TUSB8041

Hello

I am using two TUSB4041I chips to get 7 downstream USB ports. At this stage, I have just populated one IC and tried to get the host to detect the hub.

However, when I enter lsusb, I don't see the device in the list. With dmesg, I see the error, 'device no response, device descriptor read error/64, error -32

I am not sure what I have missed. Please find attached screen capture of the error and schematic. R12-18 are not populated, R19-20, R23 are not populated. I havent connected up the downstream ports to anything yet. Just trying to the get the host to see Hub controller IC.

I have checked that the voltages are stable and the clock signal also seems to be fine.

Any hints would be appreciated.

Thanks

  • 0
    TI__Guru 60870 points
    Hi Arun,

    Remove R17 unless you are implementing SMBUS. Also the pullups on SDA/SCL are not necessary unless an EEPROM or SMBUS host is used.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Prodigy 85 points

    Hi JMMN

    R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 and R23 are not placed (I am not planning on placing them either except for R11, R12, R13 and R14).

    I accidentally clicked resolved while posting but I still havent got it going.
    Is there anything else I am missing?

    Regards
    Arun

  • 0 in reply to Arun Ashok8
    TI__Guru 60870 points
    Hi Arun,

    Check that the reset is held low after the power rails ramp and that the clock starts. Also, the voltages measured on USB_VBUS and USB _R1 pins would be useful.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Prodigy 85 points

    Hi JMMN

    I can confirm that the reset is low for atleast 5ms before the rail comes up. But the clock is not present. I can see the clock come up momentarily on power up but goes away immediately.

    The voltage on USB_VBUS is around 0.45V and USB_R1 is 0V.

    I have tried adding a 4.7k pullup to the GRSTz pin. In this case, the clock comes up and stays.
    The voltage on USB_VBUS is around 0.45V and USB_R1 is 0.47V.

    Thanks
    Arun

  • 0 in reply to Arun Ashok8
    TI__Guru 60870 points
    The GRSTz has an internal pullup resistor, so typically an external pullup is not needed. It sounds like the hub is coming up and dropping into suspend (why the clock is turning on and then back off). Please confirm the upstream DP/DM connections to the host.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Prodigy 85 points

    Please see the above image. The Blue is the 1.1V rail, Pink is the GRSTz line and Green is the clock line.

    However, the host device now picks up the hub as TUSB8041. The issue was I had the pullup wired incorrectly to 0V instead of 3.3V.

    Not sure what is going on with the clock though. Will try wiring up a downstream device and see how it goes.

    Thanks

    Arun

  • 0 in reply to Arun Ashok8
    TI__Guru 60870 points

    Hi Arun,

    Glad it is up and running.  Let us know if you have any further issues.

    Regards,

    JMMN