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TUSB4020BI: USB device connectivity issue

Jihoon Choi
Prodigy 120 points
Part Number: TUSB4020BI
Other Parts Discussed in Thread: TUSB211A, TUSB216I

Tool/software:

Hi. Experts.

I am currently developing hardware using the Raspberry Pi CM4 and TI USB devices.

The diagram below shows a simplified top-level design of the hardware I am working on.

All USB HUB ICs are configured not to operate the USB power switch control.

The diagram below shows the hardware block diagram and a photo of the devices recognized on Linux.

I am currently facing a few issues with this hardware configuration:

Problems

  1. After initial power-up, all devices below the CP2108 devices (8 units) and the TUSB4020 (Yellow box) in the diagram are recognized by Linux. However, after 30 minutes or a random period, the connection drops, and the devices are either re-recognized or fail to reconnect. Please identify any potential issues in this hardware configuration.

  2. I used the TUSB211A to achieve a longer communication distance, but communication fails beyond 3 meters when using UTP cable. What additional circuits or devices are necessary to ensure communication over a distance of more than 10 meters?

    The solution must be implemented within the PCB, without using repeater or bridge devices in the middle of the line.

Additional Inquiry:

To facilitate smooth hot-plugging, what configuration is required?

The current PCB’s USB communication termination at the RJ45 connector includes PESD5V0V1BA on the power lines, and DLM11SN900HZ2L along with TPD2EUSB30DRTR on the DN and DP lines.

Please provide answers to the above issues and inquiries.

Thank you for taking the time to read the long message.

Have good day.

  • +1
    TI__Guru** 122160 points
    Jihoon Choi said:
    After initial power-up, all devices below the CP2108 devices (8 units) and the TUSB4020 (Yellow box) in the diagram are recognized by Linux. However, after 30 minutes or a random period, the connection drops, and the devices are either re-recognized or fail to reconnect. Please identify any potential issues in this hardware configuratio

    what cable length used for this issue happened, 3m?

    what connection is lost, yellow box?

    Jihoon Choi said:
    I used the TUSB211A to achieve a longer communication distance, but communication fails beyond 3 meters when using UTP cable. What additional circuits or devices are necessary to ensure communication over a distance of more than 10 meters?

    TUSB216I can work with 5m cable, for 10 m, you may need two USB2 redriver.

    A USB hub system  can  work  with  127 devices, but not  sure if  how many devcies CM4 can support, can you  remove one TUSb4041 and test again?

    Best

    brian

  • +1 in reply to Brian Zhou
    Prodigy 120 points

    Q. What cable length used for this issue happened, 3m?

    A : We used UTP cables with lengths of 1m, 1.5m, and 3m.

         During this time, the connections of TUSB4020 (Y-BOX) and CP2108 (Y-BOX) were randomly disconnected.

         However, when using USB cables of 1m and 2m, there were no disconnections for two days.

    Q. What connection is lost, yellow box?

    A : Most of the disconnections occurred with the CP2108 (Y-BOX), while the TUSB4020 (Y-BOX) experienced disconnections at a lower probability.

    TUSB216I can work with 5m cable, for 10 m, you may need two USB2 redriver.

    Q : If we are to use two USB 2.0 redrivers, how should they be implemented in the circuit?

          Could you provide any related application notes or reference circuits?

    Can you  remove one TUSb4041 and test again?

    I can remove one TUSB4041 and run the test.

    But since I'm only using 2 out of the 4 channels of each TUSB4041, removing one of the two TUSB4041s will ultimately allow me to test only 2 channels.

    Thanks.

  • +1 in reply to Jihoon Choi
    TI__Guru** 122160 points

    Hi Jihong:

       It seems the issue is cable  related, let me find out the report with 10 m cable.

    Jihoon Choi said:

    Can you  remove one TUSb4041 and test again?

    I can remove one TUSB4041 and run the test.

       This test is just to check if the issue was caused by bandwidth or not.

    Best

    Brian

  • +1 in reply to Brian Zhou
    TI__Guru** 122160 points

    Any update?

    Best

    Brian