On Wed, Nov 25, 2009 at 3:30 PM, Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx> wrote: > Hi All, > > I have a basic doubt on root hubs. > > I'm working on a media SoC which has 1 USB interface which can > function both as a host and a device (would this qualify for OTG? the > datasheet doesn't mention OTG though) and an on-chip PHY. Here's an > excerpt from the datasheet about the USB host controller: > > "The USB 2.0 Embedded Host Controller is fully compliant with the USB > 2.0 specification and the Enhanced Host Controller Interface (EHCI) > specification revision 1.0. The controller supports high-speed > (480Mbps) transfers. The controller comprehends the high-speed, > full-speed and low-speed data ranges providing compatibility with a > full range of USB devices. The full-speed and low-speed operations are > supported through the EHCI software stack via a transaction > translation layer." > > Now my question is, does the EHCI also function as a root hub? As in > the root hub is incorporated into the host controller? > > If I have to add another USB port to such a device, will it be > possible to connect it to the existing root hub? > > I'm asking this because its mentioned that the host controller also > has an on-chip PHY, and as I understand I'll have to connect my second > port directly onto the USB bus and not to the PHY interface. Is my > understanding correct? Can you point to the data sheet ? > > Thanks, > -mandeep > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
