TUSB2046B idle, disable power?

Curtis Coffee

If you have 4 devices connected to this hub, and you are only talking to one or two of them, will the others have idle conditions on their USB bus? The reason I ask, is I'd like to take advantage of the idle condition for disabling power to a few of the devices, should we not be talking to them. I know the protocol itself handles this sometimes, but wanted to make sure that I understood that correctly. thank you

over 9 years ago

0 Elias Villegas M. over 9 years ago

TI__Guru* 76130 points

Hello,

No, the USB 2.0 is a broadcast system so even if you are talking only with two of the downstream devices, the other two will be receiving the traffic, they will just detect that the traffic is not directed to them and will discard the data but this traffic will prevent those buses to enter in suspend.

You can use instructions like Clear_Port_Feature(Port Power) to remove the power but you will have to modify the USB driver to do that.

Regards.

0 Curtis Coffee over 9 years ago in reply to Elias Villegas M.

Prodigy 80 points

Thank you. Could you please expand a little on what modifications would be needed to the clear_port_feature driver call to remove power?

0 Elias Villegas M. over 9 years ago in reply to Curtis Coffee

TI__Guru* 76130 points

Sorry,

I don't have bandwidth on the driver.

The driver is property of Microsoft or Linux Community depending on your operating system.

Regards.

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TUSB2046B idle, disable power?