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  • TI Thinks Resolved

TUSB2077A: TUSB2077A show only PORTDIS

Prodigy 150 points

Replies: 26

Views: 141

Part Number: TUSB2077A

I have the first development on TUSB2077A. I designed  the circuit from datasheet Rev. F on page 16.

when I connect the hub to my host PC, my PC can't detect the usb hub.

On the hub, it show only PORTDIS light on. I have checked UP_DM and UP_DP they are connected to the chip pin with 28 ohm and DP0PUR connected to UP_DP  with 1.5 ohm.

Now I don't know what to check next?

Please tell me what I must to check next.

Thanks.

  • Hello Bawornsit,

    What is the state of the UP_DM / UP_DP lines?  Can you confirm that voltage levels and clock to the hub.  Please provide the schematic if possible.

    Regards,

    JMMN

  • In reply to JMMN:

    This is external power reduced to 5V.

    This is LDO regulator connected from +5V USB upstream power

    I connected +5V_BUSIN0 from USB_upstream power  and +5V_BUS from 5V regulator  together and provided to Power distribution switch (TPS2044).

    There are a diode on the +5V_UPBUS to prevent reverse power from 5V regulator that shown on the next picture.

  • In reply to Bawornsit Changto:

    Hi,

    I can't tell from the schemaitcs, but please confirm that DP at the hub is always connected to DP, at the connector and DM at the hub to DM at the connector as well.  The downstream facing ports need 15K pulldowns, 1.5K is too strong.  The pulldowns should be on the hub side of the 27 ohm series resistor.  Also, I would try running the hub without the EEPROM to start.

    Regards,

    JMMN

  • In reply to JMMN:

    DP and DM upstream are connected to chip pin as well with 27.2 Ohm and DP0PUR is connected as well with 1.5K Ohm.

    For downstream ports, this is my fault. however, I will change to 15K later.

  • In reply to Bawornsit Changto:

    Can you check the line states of upstream DP and DM?  What does the host report?  What operating system are you running on the host?

    Regards,

    JMMN

  • In reply to JMMN:

    My host is running on windows 10. I see. sometimes, it show device error or not recognized. Mostly, not recognized. I tested the cable connectivity is going well.

  • In reply to JMMN:

    Only PORTDIS is turning on. this mean the chip works properly? but, it can't connect to my PC only.

    The issue is not clear to understand for me.

  • In reply to Bawornsit Changto:

    Can you install usbview.exe or USB device tree viewer and share the report?

  • In reply to JMMN:

    This is a report after I connect the hub to my PC. I have compared to before connecting. They are the same.

  • In reply to Bawornsit Changto:

    Please check the line states of the upstream DP and DM, and confirm if the clock is running.

    Regards,

    JMMN

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