Thanks all for your inputs. I'll look at the options available. -mandeep On Thu, Nov 26, 2009 at 12:19 PM, Salvatore Lionetti <salvatorelionetti@xxxxxxxx> wrote: > Hi, > > in my understanding, the statement: > > "The full-speed and low-speed operations are supported through the EHCI software stack via a transaction translation layer." > > mean that as many other usb controller, no hardware ttl is provided. So i see two possibilities: > > - Use the ttl in software (as datasheet say), perhaps already provided with some kind of libraries by your vendor or > - Use an usb hub, so with an hw ttl. > > Have a good day > > --- Mer 25/11/09, Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx> ha scritto: > >> Da: Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx> >> Oggetto: basic doubt on root hubs (on an embedded SoC) >> A: "linux-usb" <linux-usb@xxxxxxxxxxxxxxx> >> Data: Mercoledì 25 novembre 2009, 08:30 >> 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? >> >> 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
