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Original question:

Linux/AM5728: USB2 test patterns through Hub

Linux/TUSB4041I: TUSB4041I hub in MSM8996 platform

user6066439
Prodigy 10 points
Part Number: TUSB4041I

Tool/software: Linux

Hi, Ti:

We used the tusb4041i hub as the msm8996 usb2.0 host's slave device. Now we  had tested the hub's downstream port's eye pattern,

but  the left canthus is not open enough, it cause the test result is fail. We had replaced the USB_R1 resistor from 9.53kΩ to 8.25 kΩ,

but the effect had not been improved.

What's the reason of this  problem? Which parameters fo the eye pattern we should adjust?

Can I tuning it by  modifying the boost value of the eye pattern register? I haven't the eye pattern

register's datasheet of tusb4041i hub, can you give me one? 

  • 0
    TI__Guru 64326 points

    Hi,

    Can you describe your application and share the eye diagram? You may be in need of a USB 2 redriver depending on the transmission media used on the downstream port. The USB_R1 resistor is what should be used to adjust the drive strength for the USB 2.0.

  • 0 in reply to Malik Barton57
    TI__Guru 64326 points

    Hi,

    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.