TUSB4041I-Q1: How to configurate the downstream ports USB_DM_DNX as high impedance state?

Iris Shen

Part Number: TUSB4041I-Q1

Hi team,

How to configurate the downstream ports USB_DM_DNX as high impedance state?

And I'd like to know the initial state of the ports USB_DM_DNX ports since there are no type description of these pins on datasheet.

over 3 years ago

+1 JMMN over 3 years ago

TI__Guru 60870 points

Hi Iris,

The states of the DP/DM pins are defined by the USB 2.0 specification. The state of these pins depends on if the port is upstream facing or downstream facing and what is the connection state of the system.

You can find the USB specifications at www.usb.org

Regards,

JMMN

0 Iris Shen over 3 years ago in reply to JMMN

TI__Expert 4002 points

Hi JMMN,

Sorry, I am still confused. Customer continues to ask how to configurate the IC to make the downstream ports(DP/DM pin) in high impedance state. Can we configurate some registers to achieve this? I find in datasheet that we have "Ioz" high impedance output current, in what conditions can measure this parameter?

Thanks!

0 JMMN over 3 years ago in reply to Iris Shen

TI__Guru 60870 points

The hub cannot force the downstream ports into a high-impedance using a register. What state is the hub in when the customer wants the ports to high-impedance? Connected / unconnected? Which ports? Is USB_VBUS high or low? Is battery charging enabled?

0 Iris Shen over 3 years ago in reply to JMMN

TI__Expert 4002 points

May you explain in what hub state some downstream ports are high-impedance? Then customer can follow your configuration. If IC in reset state whether it is possible?

The reason why they asked this is because if hub can force downstream ports into a high-impedance, it will not influence signal thus they can reduce the second switch. Please refer to the connection diagram as below.