AM3352: VBUS power switch control when using with TUSB320

Hi Oba,

Is the AM335x USB port in host-only mode or dual-role mode?

Hello,

This project itself will use only host mode. But they are also looking at DRP mode for the future.
So could you please tell me both cases, only host mode and DRP mode?

Regards,
Oba

Hi  Oba,

The host-only mode is simple, since the AM335x USB controller doesn't need to talk to TUSB320 for the mode. You only need to ground the AM335x USB_ID pin, connect USB_VBUS pin to the VBUS line. You have 3 options for VBUS power control:

1) use AM335x USB_DRVVBUS pin;
2) directly tie VBUS to 5V power rail (always on, no control);
3) let TUSB320 control the switch (I am not sure how, since I only support AM335x but am not familiar with TUSB320).

For DRP mode, AM335x USB controller has to talk to USB320 for the operational mode. But I am not sure how it should be. I think Paul will talk to the experts who support TUSB320 to understand how to design it.

Hello,

Thanks for your comment.
I believe that VBUS has to be supplied to the connector only after checking Rp/Rd status of CC pins.
So I think 1) and 2) are not acceptable and I think 3) is the best solution. I want to confirm this. 

And I'm not familiar with AM335x USB peripheral. So I'm not sure whether USB_DRVVBUS can be just connected.
Is It OK?

Regards,
Oba