USB power configurations

Forums Devices OSD335x-SM USB power configurations

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    • #6990
      Mat Mat Mahermemaher
      Participant

        Assuming I allocate both USB0 and USB1 as OTG ports, so they can act as either master or slave, is it possible to still be able to power the device from USB-only power? If so, can you advise how this can be achieved with regards connections to VIN_USB? This is a rather confusing scenario whereby:
        1. during development we want USB0 to act as a slave device for debug/development – sourcing power directly from the USB port.
        2. at runtime, we want USB0 and USB1 as host devices for peripherals – providing power as needed.

        Can’t figure out how to achieve this without jumpers – any ideas?

        Mat

      • #6992
        Neeraj Kumar Reddy DantuNeeraj Dantu
        Moderator

          Memaher,

          USB OTG functionality can be enabled by exposing the USB_ID pin to the USB connector(instead of floating or pulling to GND).

          In addition to USB_ID, special configuration is required to manage the power supply to and from the USB port in different configurations. If the port is functioning as a client port, power must be supplied to USB_VBUS+VIN_USB. If the port is functioning as a host, on board power switches should be enabled to supply power to the USB slave(done via USBx_DRVVBUS). The switching between the power in/out can be done using USB_ID(USB_ID controls USBx_DRVVBUS which can be used as enable signal to power out) and presence of VIN_USB as control signals.  If you are using a powered hub when using the port as a USB host, then no additional power configuration is necessary.

          EDIT: Updating this to add info about USBx_DRVVBUS

          Hope this helps,

          Best,

          Neeraj

           

          • This reply was modified 5 years, 9 months ago by Neeraj Kumar Reddy DantuNeeraj Dantu. Reason: Add info about USBx_DRVVBUS
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