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TUSB8041: Behavior with a USB-SD/MMC controller

Oba
Genius 17355 points
Part Number: TUSB8041

Hello,

 

This question is related to the below my post.

https://e2e.ti.com/support/interface/f/138/p/825259/3053028 

At first, I’m very sorry, the part number was wrong. It was not TUSB4020 but TUSB8041.
While the customer is also contacting to the IC vender for SD/MMC controller IC, they found it could be solved by changing Device Removable Configuration Register of TUSB8041 to “Not Removable” for the port that USB-SD/MMC controller IC is connected.

With this configuration, all Read/Write/Remove functions correctly worked.
But there is still one issue that task tray in windows shows an error, “Unknown USB device (Port Reset Failure)” like the below figure(Sorry, it’s Japanese).

Then I have two questions.

  1. Is there any registers that can affect this issue like Removable/Not Removable configuration?
  2. The customer don’t say this issue is due to TI, but they would like to understand why changing to “Not Removable” could solve this issue and there are still error message on the task tray. Could you please give me something comment?

 

Regards,
Oba

 

  • 0
    TI__Guru 60870 points

    Hello Oba-san,

    Setting a port as removable or non-removable through the registers doesn't change the hub's behavior directly, it will only change what the hub reports to the host in its usb descriptors.  This information may impact how the host accesses the hub and its downstream devices.  Is the connected downstream device a USB 3.0 or USB 2.0 device?  For a quick test, could they check if changing the setting of FULLPWRMGMTz impacts the system behavior?

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Genius 17355 points

    Hello JMMN,

    The downstream device is USB2.0 device. The customer is on vacation this week. I'll ask to test changing FULLPWRMGMTz next week.
    What kind of result could happen by this change?

    Regards,
    Oba

  • 0 in reply to Oba
    TI__Guru 60870 points

    Hi Oba,

    The hub reporting as not having downstream port power switches (FULLPWRMGMTz = 1) changes the "powered off" behavior of the downstream ports for USB 3.0.  For USB 2.0, there is no defined state machine difference based on power switches, but the driver behavior may change.

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Guru 60870 points

    Hi Oba,

    I'm closing this thread for now, just post a response to reopen it when the customer has more input.

    Regards,

    JMMN