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TUSB2046I: Problem of plugging after unplugging

Dice-K
Mastermind 7194 points
Part Number: TUSB2046I
Other Parts Discussed in Thread: TUSB4041I,

Hello.

If I plug the USB Device of Port-2 after unplugging it, the HOST of Port-1 is judged as low speed.


Is this behavior correct?

I want to use it at high speed mode.

Please let me know the simple countermeasure method.

Regards,
Dice-K

  • 0
    TI__Guru 64326 points

    Dice-K,

    TUSB2046I is a full speed hub not a high speed hub. TUSB4041I is a high speed hub which may be more suitable for your application. 

  • 0 in reply to Malik Barton57
    Mastermind 7194 points
    Hello Malik,
    Thank you for your reply.

    I'm sorry, my posting was a typo.

    I want to use it at full speed mode.

    Please let me know the simple countermeasure method.

    Best regards,
    Dice-K
  • 0 in reply to Dice-K
    TI__Guru 64326 points

    Dice-K,

    In you figure is port 1 the upstream port of TUSB2046I?

  • 0 in reply to Malik Barton57
    Mastermind 7194 points

    Hi Malik,
    Thank you for your reply.

    Yes, that's right.
    The Port-1 is a upstream port.

    Is this related to the problem?

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Guru 64326 points
    Dice-K,

    The USB host on the upstream sets the "speed" of the bus according to the capabilities of the USB device in most cases. What USB device are you using? Is this device a full speed compatible device? There are many reasons this could be happening dealing with schematic and layout issues. Can you post the schematic and layout for this design?
  • 0 in reply to Malik Barton57
    Mastermind 7194 points

    Hi Malik,
    Thank you for your reply.

    I post the schematic and layout for this design.

    Please let me know problems.

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Guru 64326 points

    Dice-K,

    What is the device you are using for this test? Also can you probe DP and DM to see if upon connection of downstream device DM or DP is pulled up?

  • 0 in reply to Malik Barton57
    Mastermind 7194 points
    Hello Malik,
    Thank you for your support.

    > What is the device you are using for this test?
    HOST : Renesas RX-seires Microcomputer
    USB Device : It is not a memory but a device that mounts a microcomputer and communicates.
    Since our company has not developed, we do not know the contents.

    > Also can you probe DP and DM to see if upon connection of downstream device DM or DP is pulled up?
    The DP of the downstream device is pulled up.

    Best regards,
    Dice-K
  • 0 in reply to Dice-K
    TI__Guru 64326 points
    Dice-K,

    Just to confirm are you seeing the Host, the HUB, or the Device drop into low speed mode? Also how are you determining that it is dropping into low speed mode?
  • 0 in reply to Malik Barton57
    Mastermind 7194 points

    Hi Malik,
    Thank you for your reply many times.

    My customer's information is as follows.

    I do not know if it actually drops into low speed mode.

    It judges by software.

    By plugging in and out of the device connection side (DP1,DM1), it is confirmed that the PORT_LOW_SPEED bit is set for the status acquired by GetPortStatus on the Port-1 (DP0,DM0).

    It is the question whether this is abnormal or not.

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Guru 60870 points

    Can you post the entire port status returned?  The port_low_speed bit may be set due to an error or disconnect condition.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Mastermind 7194 points

    Hi JMMN,
    Thank you for your support.

    I attach the acquired log.

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Guru 60870 points
    Hi Dice-K,

    The USB host is not changing from full speed to low speed. The port status that is changing is on Port 1 - the Ethernet gadget is connecting at full speed, then disconnecting and reconnecting at full speed. I don't see any device being connected at Port 2? Can you confirm what is being connected / disconnected in the log?

    Thanks,
    JMMN