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TUSB8041A: TUSB8041: Asking for how to report the TUSB8041 upstream report the OC event to CPU

SHH
Mastermind 32186 points
Part Number: TUSB8041A
Other Parts Discussed in Thread: TUSB8041

Hi Team,

We have question from the CPU side for the AMD platform. to enable the OC function with USB PROTOCAL instead of using OC pin to CPU. And that makes each USB port has its own on/off action.
please helpf ro the questions.
  1. When OC triggered, who cut off the USB LINK, by HOST or by 8041?
  2. Can the OC event automatically resume after triggered? (through USB PROTOCAL)
  3. Can you give us the successful case to trigger OC and resume automatically. With which platform, which Window version?

Thanks,

SHH

  • 0
    TI__Expert 7395 points

    Hello Scott,

    1.- When an overcurrent event is detected on a downstream port (by a power switch or other mechanism monitoring Vbus), that should be reported to the TUSB8041A by asserting the corresponding OVERCURx terminal low. In consequence, the TUSB8041A will automatically set the corresponding PWRCTLx terminal (in accordance to the polarity configured through the PWRCTL_POL terminal) to indicate the power switch to shut down VBus from the downstream port. Additionally, the TUSB8041A will set an internal flag indicating an overcurrent event occurred, and when the USB Host controller requests the PORT STATUS to the TUSB8041A, the data will notify the fault condition to the host. 
     
    2.- The host controller driver can send a command to the TUSB8041A to re-enable the downstream port once the overcurrent flag is being cleared from the reported PORT STATUS

    3.- As part of the USB Compliance testing, it is a common practice to generate a short circuit between VBus and GND on the downstream port connector to trigger the overcurrent event. Windows 10 is used.

    Regards,
    Jorge.

  • 0 in reply to Jorge Llamas (SWAT)
    TI__Mastermind 32186 points

    Hi Jorge,

    Do you have idea know if this OC behavior is supported by the following OS? ( We are server team and use server OS)

    customer says that their project deson’t work well with some OS

    1. 2012 R2

    2. 2016

    3. Linux Red Hat

    SOC CPU vendor think it’s more possible there is something wrong in OS. Obviously Linux and 2016 behavior is different.

    But SOC vendor don’t have tool to show it. Do you have a tool to check it or it’s known issue in your side?

    SOC vendor will do more on the TUSB8041 HUB. Please provide your comment if you see the similar request before

    thanks,

    SHH

  • 0 in reply to SHH
    TI__Expert 7395 points

    Hello Scott,

    The TUSB8041A will automatically turn port power off as long as overcurrent input is held low.  If the USB power switch stops asserting the overcurrent, the hub will re-enable the port power if the host has not already logically turned off the port power.

    • Typically Windows platforms require the hub to be re-enumerated or power cycled before the drivers will re-enable power to the downstream ports.

    • Some Linux builds may not actually configure the interrupt endpoint of the hub that reports overcurrent or they may ignore the bits if they do read them

    Regards,

    Jorge