USB downstream devices

[rfiller73]

Hello Octavo —

How are the USB downstream devices connected to X5B or X4 connectors get powered up? There is no circuitry designed-in on the schematic that enables power to downstream devices. Is it done via OS? If it is, what is the exact method of communication with USB hub to configure appropriate registers? I2C, UART, ?

Please advice.

Thanks for support.

Roman

 

[Neeraj Dantu]

Roman,

U15(TPS2051) provides power to the USB devices. You can see that the output of this chip connects to the VBUS lines of each of the USB ports. This power switch is enabled by USB1_DRVVBUS signal of the USB1 peripheral controlled by the OS.

Please let us know if you have more questions.

Best,

Neeraj

[Author]

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