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TUSB8041A: TUSB8041A status indication problem

Zhang Peng
Prodigy 45 points
Part Number: TUSB8041A


The project involves designing a multi-port hub using the TUSB8041A, and the following issues have been encountered:

image.png

  1. In the screenshot, I have connected LEDs to HS_SUSPEND, HS_UP, SS_SUSPEND, SS_UP, and configured the register stsOutputEn in the EEPROM to the enabled state. However, when I switch the upstream port connection between HS and SS, the corresponding LEDs fail to indicate correctly.

  2. The manual mentions that these four pins have other multiplexing functions, which require voltage sampling during the reset period. Given this, how can I ensure that the pins are correctly configured during reset? How can I both guarantee the proper indication of these statuses via LEDs and ensure the correct functional configuration? If both cannot be achieved simultaneously, how can I at least ensure the correct display of the LED statuses.

  • 0
    TI__Guru**** 151510 points

    Hi :

       Hub upstream port should be connected  as SS and HS at same time. Did you see TUSB8041A SS and HS from system device manager?

       After reset, these signals indicate the SuperSpeedHS  USB status  of the upstream port .

    Best

    brian

  • 0 in reply to Brian Zhou
    Prodigy 45 points

    Forgive me for not understanding your help.After the PCB is fabricated, the EEPROM is first programmed. Then, the basic functions of the hub are tested. After connecting to the upstream port, a mass storage device is used to test each downstream port individually, and every port functions as expected. However, during the testing of the status indicators: if everything is normal, when connected to a USB 3.0 upstream port, the SS_UP indicator LED should light up, and when connected to a USB 2.0 upstream port, the HS_UP indicator LED should light up. But in reality, one of these two LEDs does not change accordingly with the alteration of the upstream port.

  • 0 in reply to Brian Zhou
    Prodigy 45 points

    Are you suggesting that the reason I'm seeing abnormal status indication after connecting to USB 3.0 is because USB 3.0 includes USB HS?

  • 0 in reply to Zhang Peng
    TI__Mastermind 45251 points

    Hi,

    Yes, a SS upstream connection must also support a HS upstream connection as the HUB must be backwards compatible on the downstream ports. A SS connection on the upstream must still allow for a HS connection on the downstream. 

    In an application called USB Tree Viewer you will be able to see which ports enumerate, and at what speeds they are set to. 

    I'm not sure I follow which LEDs are on, so can you confirm?

    Can you share which status LEDs are on in the following scenarios:

    1) SS connected Upstream

    2) HS connected Upstream

  • 0 in reply to Vishesh Pithadiya
    Prodigy 45 points

    The hardware is not currently in my possession, so I can't run immediate tests. However, could you help clarify the correct states of HS_UP and SS_UP under the following three scenarios:

    (1) The upstream port is connected only to a computer's USB 2.0 port with HS signaling.
    (2) The upstream port is connected to a computer's USB 3.0 port with both HS and SS signaling.
    (3) The upstream port is connected only to a computer's USB 3.0 port with SS signaling.

  • 0 in reply to Zhang Peng
    TI__Mastermind 45251 points

    Hi,

    The outputs should be as follows:
    (1) only HS LED is on

    (2) SS and HS led is on

    (3) Have not tested this, so I am unsure. Should be only SS led on.