Re: [usb] usb clarifications

[Ravi Kumar <ravikumar_vlsi@yahoo.co.in>]

hi all
I have a clarification on usb.
Would some tell me 

1)what is the packet structure 
for assigning an address to the device.

is the command is 
set_addres 
followed by a data phase for  the address to be
assigned to device.


2)
do we assign a unique address to an endpoint of the
device or what ?


regards
Ravikumar


 --- Vikas T Rao  <vikasraot@myw.ltindia.com> wrote: >
** 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
> 
> 
> >>> ravikumar_vlsi@yahoo.co.in 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
> <senthilnadesan@rediffmail.com>
> 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
> > >
> > >
> > >
> > >
> > >  --- 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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