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TUSB2046B: About reset pulse width

Masanori Tachibana
Genius 5350 points
Part Number: TUSB2046B


Hi support team,

I have a question about the reset pulse width of TUSB2046B.
According to the data sheet, the recommended pulse width of reset is from 100 μs to 1 ms.
Is it OK even if the pulse width is more than 1 ms?
Or, what kind of problems will happen if it becomes 1 ms or more?

Best regards,
M. Tachibana

  • 0
    TI__Guru 60870 points
    Hi Tachibana-san,

    The issue with a longer reset for USB full speed devices is that the host will see the external pullup on the DP line and attempt to access the hub. If the hub does not respond because it is still held in reset the host may mark the port as disconnected or in error state and not enumerate the hub when it does come out of reset. This is typically more of a concern in embedded applications where the host and hub are already connected at power on reset.

    www.ti.com/.../slla314.pdf

    Regards,
    JMMN
  • 0 in reply to JMMN
    Genius 5350 points

    Hi JMMN-san,

    I'm sorry for my very late reply.
    I finally understood what you taught.
    Thank you very much for teaching me.

    Best regards,
    M. Tachibana