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DM365-USB-VBus

Velmurugan
Intellectual 2220 points

In our video conferencing development project we use 2 DM365. We are planning to use USB bus for communicating between them.
We need a clarification - what to do with USB_VBUS pin in both DM365s. Since we are connecting the USB on-board, we do not require a VBUS supply. In this case
how to connect these pins in both devices. (Plz note that one DM365 will be USB Host and the second will be a USB Device

Vel

  • 0
    TI__Mastermind 41665 points

    My understanding is that USB_VBUS is primarily there to verify that the 5V VBUS rail is actually up at 5V, so that the device can detect an under voltage condition on the USB. However the spec is written such that USB_VBUS is expected to exist, as the USB was not intended to be used outside of a standard USB context like you intend to do, so there is some risk involved in leaving the USB_VBUS line in a non 5V state, in particular I believe there are logical state machines within the USB controller that expect USB_VBUS to be in certain states depending on your operating mode which may get confused if you do not power USB_VBUS properly.

    Before designing a custom PCB without a VBUS rail you may want to try testing this out with some existing hardware like an EVM, cut the VBUS line and modify the driver to ignore the VBUS below threshold interrupt and see if it will still work .