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Re: [usb] usb clarifications
Hi Ravi,
Answers are here
for que.1 :
In case of Set Address request we donot have an data stage.
The device address is send in the wValue field of the Setup Data.
for que2:
The device are assigned an unique address.
Whereas every Endpoint is distinguised by the Endpoint Number and
the direction it support and with the device address.
I hope this are clear now.
Regards
R.Rajaganapathy
----- Original Message -----
From: Ravi Kumar <ravikumar_vlsi@yahoo.co.in>
To: <usb@opencores.org>
Sent: Wednesday, June 19, 2002 7:45 PM
Subject: Re: [usb] usb clarifications
> 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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