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Re: [usb] usb clarifications




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
>
>
>
>
>  --- govindsrajan@hotmail.com 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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