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Re: [usb] usb clarifications
** Proprietary **
hi ravi,
hub should recognise the device attachment and detachment. this will be indicated to the host by the status change endpoint mechanism if it is a hub, if hub acts as root hub then it will be reported in the port control and status register. i suggest you to go through the chapter-->11 refer 11.12 hub controller.
...vikas
>>> [email protected] 06/17/02 09:45PM >>>
hi all,
I understand that usb host polls devices in frequent
intervals for periodic kind of transfers (namely
Isochronous & Interupt Transfer type) , but with what
frequency that it polls the Hub's Status endpoint for
detecting the attachment & Detachement of usb devices.
I beleive the frequency that it polls the Hubs status
Descriptor is relatively higher -- Would u pls clarify
whether i have understood correctly
Regards
Ravikumar
--- senthil nadesan <[email protected]>
wrote: >
> Hello ravi,
> Gothrough the lines within codes,it is taken from
> the usb
> specification 1.1 in the page 231.
>
> "In the downstream direction, hubs operate
> in a broadcast
> mode. When a hub detects an SOP on its
> upstream port, it establishes connectivity to all
> enabled
> downstream ports. If a port is not enabled, it does
> not propagate packet signaling downstream."
>
> With regards
> Senthil
>
>
> On Fri, 14 Jun 2002 Ravi Kumar wrote :
> >hi all,
> >In USB .
> >Consider the OUT transaction ,
> >will the host controller
> >sends the data to all the devices in broadcast or
> >will it select particular hub where the devices is
> >anchored & send the data to that particular hub .
> >
> >Pls reply
> >Regards
> >Ravikumar
> >
> >
> >
> >
> > --- [email protected] wrote: > Hi,
> > >
> > > During an enumeration process, what should be
> the
> > > address value in
> > > the Setup Token. Is it always "zero" or the
> > > address value of the device
> > > which is being sent in "Set Address" command
> in
> > > the data phase?
> > >
> > > SetUp Token (Sync,Pid,Addr,Endp,crc5,Eop) ;
> Addr
> > > = 0 / [1-128] ?
> > > Data (Sync,Pid,Data0,crc16,Eop);
> //
> > > Data0 has the command
> > >
> > > If I change the address of a device, what is
> the
> > > address value in the
> > > Setup Token. Is it zero or the old value?
> > >
> > > A quick reply is appreciated.
> > >
> > > Thanks
> > > Govind
> > > --
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