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AM3352 USB bus reset

Nomo
Guru 16800 points
Other Parts Discussed in Thread: AM3352

Hello,

I have three questions for the bus reset of USB on AM3352.
Linux kernel version is PSP 04.06.00.08.

1. For PSP 04.06.00.08, is the procedure implemented to be done the bus reset of USB by software?
2. If yes, please let me know the condition to be done the bus reset of USB.
3. How can I know whether the bus reset is occurred?

Best Regards,

Nomoto

  • 0
    TI__Guru**** 393215 points

    Hi,

    I will forward this to the USB experts.

  • 0
    TI__Guru**** 168471 points

    Yusuke Nomoto said:
    1. For PSP 04.06.00.08, is the procedure implemented to be done the bus reset of USB by software?

    Yes.

    Yusuke Nomoto said:
    2. If yes, please let me know the condition to be done the bus reset of USB.

    Many conditions can trigger bus reset, for example, the controller driver to implement USB protocol, the class drivers to handle packet error, or the user space application to implement the software requirement.

    Yusuke Nomoto said:
    3. How can I know whether the bus reset is occurred?

    You could use a scope to capture the signal.

  • 0 in reply to Bin Liu
    Guru 16800 points

    Hello Bin-san,

    Thank you for your reply.

    I have one more question.

    How can I know the bus reset of USB from the log file?

    Best Regards,

    Nomoto

     

  • 0 in reply to Nomo
    TI__Guru**** 168471 points

    Yusuke Nomoto said:
    How can I know the bus reset of USB from the log file?

    The Linux USB drivers do not always print log message when bus reset happens. Why you care about bus reset events?

  • 0 in reply to Bin Liu
    Guru 16800 points

    Hello,

    Thank you for your reply.

    I'm investigating the reason why the USB bus disconnection is occurred.
    On my customer's board, the USB bus disconnection is occurred, regardless the USB device is still physically connected on the USB bus.
    I assume the bus reset invokes the USB bus disconnection.

    Best Regards,

    Nomoto

  • 0 in reply to Nomo
    TI__Guru**** 168471 points
    What is the USB device? high- or full- speed?
    The disconnect happened at the idle state or during USB data transfers?
    Do you have any log showing the problem?