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AM5728: usb1_xx pins for USB2.0 and USB3.0

Guru 10235 points
Part Number: AM5728

Hello, TI Experts,

 

Our customer sent us questions about USB of AM5728.

They would like to use usb1_xx pins for USB2.0 and USB3.0.

 

Question:

1: usb1_xx pins automatically changed from USB3.0 to USB2.0, if USB3.0 connection fails.

     Is this understanding correct?

2: Could you tell us USB2.0 and USB3.0 initialize sequence?

       - Initialize sequence is "USB2.0 -> USB3.0" or

       - Initialize sequence is "USB3.0 -> USB2.0" or

       - Both USB2.0 and USB3.0 are initialized at the same time.

       Which is correct?

 

Best regards,

  • Hello Matusan,
    1) USB2.0 and USB3.0 use separate and parallel signal pins. As such, the pins do not change functionality regardless of connection type.
    2) USB3.0 uses far-end terminations to determine if a link partner exists or not. If a USB3 link partner is found, it will be enumerated first. If this enumeration fails, the link will fall back to USB2. If no USB3 link partner is found, the controller will then look for (and enumerate if found) any USB2 device.

    I hope this helps.
  • Hi,

    Thank you very much for your kindness.
    I really appreciate your help.
    I will send the answer to the customer.

    We would appreciate if you tell us the answer/comment about initialize sequence of customers question as below?
           - Initialize sequence is "USB2.0 -> USB3.0" or
           - Initialize sequence is "USB3.0 -> USB2.0" or
           - Both USB2.0 and USB3.0 are initialized at the same time.
           Which is correct?

    Best regards,
  • Matusan,

    My previous response answers this question. If you need me to choose from the 3 you've listed, #2 is closest to being correct.

  • Hi,

    Thank you very much for your kindness.
    I really appreciate your help.
    I will send the answer to the customer.

    Best regards,