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TUSB8041: Port configuration and clock input

Expert 7950 points

Replies: 3

Views: 124

Part Number: TUSB8041

Hello,

 

I have some questions for TUSB8041 configuration.

 

1.

Only one port(PORT1) is connected to external and power control is required for this port.

All other 3 ports(PORT2-4) are connected internally and power control is not required for them.

In this case, does the below configuration make sense?

 

FULLPWRMGMTz/SMBA1/SS_UP = 0

Unused OVERCUR2-4 = 10K ohm external pull-up

Unused PWRCTL2-4/BATEN2-4 = leave open

 

2.

If using a port for only USB2.0, is it OK to leave open for USB_SSTX and USB_SSRX pins?

 

3.

I want to use external clock source for input clock.

But the external clock is 3.3V signal. So I’m considering to use it with a resistor divider.

Does this way work? If it could work, how much ohms is good for this?

 

Regards,

Oba

  • Hello Oba-san,

    1. I would set FULLPWRMGMTz = 1, the other settings are correct.
    2. Yes
    3. This would be determined by the clock source, not the TUSB8041, but typically low value resistors are used 100 ohm / 133 ohm, etc.

    Regards,
    JMMN
  • Expert 7950 points

    In reply to JMMN:

    Hello,

    Thanks for your answer.

    Regarding 1, could you tell me why  FULLPWRMGMTz = 1 is better than 0?

    Regards,
    Satoshi Obata

  • In reply to Oba:

    Hi Oba,

    If any of the ports are not fully power managed (power is always on or not controlled by PWRCTL outputs of the hub), then the hub should be marked as not fully power managed.

    Regards,
    JMMN

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