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TUSB551: Settings of TUSB551 and the identification of USB3.0

sherry yang
Prodigy 240 points
Part Number: TUSB551
Other Parts Discussed in Thread: TUSB7340

Our customer use TUSB551 and USB3.0 has 2 ports. 

TX is DE pull-up, EQ & OS----suspended, RX----all suspended;

Between the redriver and connector, Port 6 is 1.2inch longer than Port 5 of RX, and 2inch longer of TX; The cable length between the redrive and the controller is about 4inch;

Issue:

boot into system, can identify USB3.0 U disk, once reboot, the U disk lost and the the probability is 100%; 2 U disk can be duplicated

Analysis:

After pulling down the external redriver DE of RX, both port5 and port6 can be recognized normally after restart; However, port6 will not recognize one U disk after restart;

Customer also do other pull-up and pull-down test, the good state is that 2 disks can be recognized by port5 while 1 usb disk cannot be recognized by port6 after restart; 

So, customer want to know the settings of TUSB551 and the identification of USB3.0

  • 0
    TI__Guru 64326 points

    Hi,

    DE is related to TX of TUSB551. What is the total distance between TUSB551 and Port 5? Port 6? Can the customer measure the signal quality from Port 5&6 with any eye diagram? this will help to evaluate the TX direction. There could be some receiver termination issues after reset. Is this a power cycle and not a low power mode reset? During this "reset" is TUSB551 power cycled? 

  • 0 in reply to Malik Barton57
    Prodigy 240 points

    Hi,

    Customer have confirmed that the detecte issue is not related with the trace distance. They reboot the platform, it will be fail to detecte, but if they power off then power on the system, it will be OK!

  • 0 in reply to sherry yang
    TI__Guru 64326 points

    Hi,

    This problem means that here may be some issues on the RX side. Is this a power cycle and not a low power mode reset? During this "reset" is TUSB551 power cycled? Could you describe the application a bit more? Are there two TUSB551 device, one per port? Are they only placed on the TX side or RX side? 

  • 0 in reply to Malik Barton57
    TI__Guru 64326 points

    Is there any more support needed for this issue? If so please reply with any relevant details so that I can further assist you. For now I will be marking this thread as "TI Thinks Resolved". If you have resolved your issue, please post the solution to the original problem/post for others with similar issues.

  • 0 in reply to Malik Barton57
    Prodigy 240 points

    Hi Malik,

    Finally,we found that the GRST signal changed to be low when we reboot the system,and the issue will be occured,

    We found that some register are controled by this GRST signal,like as table 74 in the datasheet,

    We modified the signal GRST maintain always high level when we reboot the system,then the issue will be disappear.

    So,could you help to find out the root cause fo us?thanks!

  • 0 in reply to sherry yang
    TI__Guru*** 144745 points

    GRST signal from USB host?

  • 0 in reply to Brian Zhou
    Prodigy 240 points

    Hi Brian,

    Yes,we used the USB controller TUSB7340IRKMR,the signal GRST is the input pin A15 used,

    If the GRST have a low pulse when we reboot the system,we can duplicate the issue,

    but when we remove the low pulse and the signal as a high level when reboot,the issue could be OK.

    So,we want to know what is the root cause?

  • 0 in reply to sherry yang
    TI__Guru 64326 points

    Hi,

    It is possible that TUSB7340 was not being configured correctly after reboot. Was power removed from TUSB7340 and/or TUSB551 during system reset? Did the USB device stay connected during reset?

  • 0 in reply to Malik Barton57
    TI__Guru 64326 points

    Is there any more support needed for this issue? If so please reply with any relevant details so that I can further assist you. For now I will be marking this thread as "TI Thinks Resolved". If you have resolved your issue, please post the solution to the original problem/post for others with similar issues.