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TUSB211: Asking for the TUSB211 device cannot detect issue

SHH
Mastermind 32166 points
Part Number: TUSB211

Hi Team,
Customer designs TUSB211 on the host application
Customer do the experiemnt with and w/o TUSB211.

Could you please provide your comment why the USB2.0 device sometimes fail with TUSB211?

Experiment:
Customer tested without TUSB211 USB Conditioner for 10 cycles :
With TUSB211: pass x6, fail x4 (the test result is below)
Without TUSB211: pass x10, fail x0

Pass scenario, D- high level is normal (3V) and we can see low pulse by HOST perform reset, keyboard is functional


Fail scenario, D- high level is around 1V, keyboard is not functional.
After re-plugging USB cable, then D- will become to normal (3V), then HOST can perform reset and keyboard is functional

Thanks,
SHH

  • 0
    TI__Mastermind 36085 points
    Hello SHH,

    Please confirm whether the keyboard is actually connected @ High speed, The TUSB211 is only active when it detects a HS connection, but most of the keyboards connect using full speed instead.

    Regards,
    Diego.
  • 0 in reply to Diego Cortes
    TI__Mastermind 32166 points

    Hi Diego,

    Customer is going to MP next month. please help for the questions. 

    1.Does that mean TUSB211 cannot support most of keyboard at the market? Could you please let me know where the description "TUSB211 only active when it detects a HS connection" is?

    2. How to confirm the keyboard is only using full speed? customer confirm the keyboard is the low speed device.

    3.the d/s page 7 said it can support LS and FS mode. If TUSb211 is not active, why the USB keyboard will be fail? 






    Thanks,
    SHH

  • 0 in reply to SHH
    TI__Mastermind 32166 points
    Hi Team,
    Would you please help?

    Thanks,
    SHH
  • 0 in reply to SHH
    TI__Mastermind 36085 points

    Hello,

    Here is my answer to your questions: 

    1. The TUSB211 should support any full/low speed device since it is inactive.
    2. You can confirm the device connection speed by using a usb viewer software like the USBtreeViewer. Plesae provide the actual speed connection of the keyboard when the issue occurs.
    3. I would like to see a scope capture of  ENA_HS, VCC and VREG when the issue occurs.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    TI__Mastermind 32166 points

    Hi Diego,

    thanks for reply. I will checked with customer for the ENA_HS, VCC and VREG waveform.

    Please refer to the the waveform we measure.

    CH1 : VCC

    CH2 : RST

    CH3 : D+

    CH4 : D-

    1. fail waveform

    2. pass waveform

    here is the speed information.

    Thanks,

    SHH

  • 0 in reply to SHH
    TI__Mastermind 32166 points

    Hi Diego,

    Please refer to the scope capture.

    The conditioner seems detect High speed mode when the symptom occurred.

    1. fail case

    2. pass waveform

    Thanks,

    SHH

  • 0 in reply to SHH
    TI__Expert 3655 points

    Your observations is correct hs is being detected and low speed will fail.

    Looks like for some Reason the host has hs termination  enabled when VCC and reset are applied to 211. If Host hs termination is enabled for at power up they need to delay 211 reset until host us termination is disabled. Add large cap on 211 reset pin and delay reset to see if the problem goes away.