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TUSB2077A HUB Device not recognized

SATTAR MALOKANI
Intellectual 555 points
Other Parts Discussed in Thread: TUSB2077A

Hi All,

I have designed the hub schematic using TUSB2077A chip, When i attached device to pcit shows as device not recognized and in windows device manager it shows as unknown device. On the schematic isolation chip ADuM4160 is not used on pcb. I searched on the forum all possible method tried almost every thing but did not work. Before making PCB i sent my schematic to Mr. Joel for review.

I am attaching my schematic here please check if something is wrong there that i can not figure out.

Thanks

Sattar Malokani 

  • 0 in reply to SATTAR MALOKANI
    TI__Mastermind 18655 points
    Hello Sattar,
    According to the USB 2.0 spec. the pull-down terminators on downstream facing ports are resistors of 15 kΩ ±5% connected to ground. Use this value instead of 215k.
    I also suggest checking signal integrity in the in the upstream ports and clock input.
    Could you provide some trace captures using a USB protocol analyzer between the host and the first TUSB2077A?
    I'm sending your schematics to another expert in order to find any error.
    Regards,
    Joel
  • 0 in reply to Joel Jimenez0
    Intellectual 555 points

    Hi Joe,

    I changed the resister from 215k to 15k values, and i disconnected the second tusb2077a chip from my pcb. still the device is recognized as unknown device. And I am not connecting any device to the downstream ports. Enumeration is not successful and device is not recognized. 

    And during start-up I can see the Crystal signal (6Mhz clock signal) for very short period, after that clock signal disappear and suspend pin shows 3.3v, and message appear on windows as " Device not recognized". please help solve problem,

    regards.

  • 0 in reply to Joel Jimenez0
    Intellectual 555 points
    Hi Joel,
    I changed the reset circuit resistor from 15k to 20k now the device is enumerated. And I also connected one device to down stream that is also recognized. But there still exist one big problem. Some times device is recognized and most of the time device is not recognized. In PCB i am only using first TUSB2077A chip second one i have disconnected.
    My OS is windows 7 & 64bit.

    And interesting this is that when I connect my PCB device through already purchased USB Hub 2.0 then all time it is recognized.
    And when I directly connect to my PC USB port then sometimes it enumerates and most time do not. Please help me figure out the problem; I really do not understand what is going on. My schematic is already attached in my first post.

    Thanks

    Regards

    Sattar Malokani
  • 0 in reply to SATTAR MALOKANI
    TI__Mastermind 18655 points

    Hello Sattar, 

    I think it could be a reset issue. Please, try using a 15kOhm resistor and a 1uF capacitor.

    Regards

  • 0 in reply to Joel Jimenez0
    Prodigy 160 points
    Hi,
    Saw your schematics. Try using 10k ohm & 0.1uF for reset pin of 1st usb Hub (U5). The 2nd USB hub only starts enumerating only after the 1st gets enumerated. The 1st USB hub (U5) enumeration is completed only after 300ms and only then the 2nd's enumeration starts. so please change the RC values for 2nd USB Controller (U6) so that it could wait until U5 is enumerated. Also try to update the Driver (online) for 1st USB Hub.
  • 0 in reply to POORNAKUMAR A M
    Intellectual 555 points
    Hi Poorna Kumar,

    Thank you for reviewing my schematic, the reset circuitry to both hub (U5 and U6) is common, would you please make clear what you mean by change second RC value of. There is only one RC value that is used on both.

    Now I will try 10kohm and 0.1uf and will let you know. And interesting thing is that when i connect usb hub to external hub both are recognized U5 and U6. When connecting directly to PC port both did not recognized.

    thanks,

    Sattar Malokani
  • 0 in reply to SATTAR MALOKANI
    Intellectual 555 points
    Hi poornam,

    I tried your recommendation 10kohm and 0.1uf but it did not enumerate, RC is only one for both and physically tied in pcb and is difficult to separate. If you have any suggestion please give me. With already purchased hub it is recognized,

    @ TI please look at my problem, I have oscilloscope with only two channels so it is difficult to capture all signals.

    thanks.

    sattar malokani
  • 0 in reply to SATTAR MALOKANI
    Prodigy 160 points
    Hi,

    when the Hub is connected to the PC, the 1st controller (U5) gets enumerated (total time to complete enumeration: 300 ms) during this time the 2nd hub (U6) remains OFF. The reset must happen within 1.2 ms after Vcc of HUB Controller reaches its 90%. Only after U5 is Enumerated & initialized, U6 will start initializing. So there must be 2 seperate RC circuit, 1 for U5 (with 10 to 15 K ohm and 0.1 uF) and 2nd RC circuit for U6 to reset after U5 (300ms+X) x is unknown to me. Please look at the timing in the datasheet.
  • 0 in reply to POORNAKUMAR A M
    Intellectual 555 points
    Hi,

    now i completely remove second hub (U6), and want to enumerate first hub (u5) with your configuration 10kohm and 0.1uf capacitor. every time it shows up device not recognized, and now i connected with already purchased hub and it is recognized. I have tried many configuration of reset (RC) but it did not solved problem, I still can not understand where the problem is.

    If you have other suggestion please give, in your schematic is it working fine, may i have your schematic please (sattar.malokani@gmail.com)

    thanks
  • 0 in reply to SATTAR MALOKANI
    Prodigy 160 points

    Hi,
    Have you tried to update your driver online? and can you try using 27pF (suggested in datasheet) / 33pF caps in the oscillator circuit!. Also check if your PCB Layout follows USB design guidelines found in 'USB.org'.

    According to what you say your Hub gets detected, but not completely. So this might only be issue related to #timings.

  • 0 in reply to POORNAKUMAR A M
    Intellectual 555 points
    Hi,

    Thanks for your immediate reply, as I understand this is generic hub and do not need driver and I am using windows 10 home edition. Now I'm out of office will try these capacitor tomorrow. Hub gets detected when I connect my pcb with already purchased hub 2.0, when I connect peripheral devices to my pcb they all are detected and recognized.

    Only problem now I'm getting is that it did not recognize when I connect my device to pc usb port. but some time it enumerate but when enumeration is successful then downstream devices recognized.

    Thanks
  • 0 in reply to SATTAR MALOKANI
    Prodigy 160 points
    Hi,
    I'm actually using the same hub with self powered 7 port configuration. but am stuck with a next level problem i.e., No downstream port's getting detected. I am not sure of the cause of the problem. Also I have all the connections similar to that of your Circuit but I have not implement USB isolater. The PCB Layout (To follow USB design guidelines) might be a problem in your case too that's what I heard from an expert here.
  • 0 in reply to SATTAR MALOKANI
    TI__Mastermind 18655 points
    Hello Sattar,
    Could you provide your update schematics, I want to know what you have changed on it. Also, have you tried connecting the hub to a different USB host or a different PC?
    Regards,
    Joel