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Re: [usb] usb clarifications



** Proprietary **

ya....what Govind said is right. the packets are not broadcasted.

i suppose the resume signal is the only one which can be broadcasted inorder to wake up all the devices from their suspend state.

>>> govindsrajan@hotmail.com 06/15/02 05:28AM >>>
Hi Ravi,

    The host always sends data to a particular device address or an 
    endpoint in the device. The address and endpoint are sent in the 
    token phase which is prior to the data phase.  

    I don't think there is any broadcast mechanism in USB since host
    always talks to a specific address or an endpoint. Can anyone clarify
    on this?

    Thanks
    Govind


----- Original Message ----- 
From: Ravi Kumar <ravikumar_vlsi@y... > 
To: usb@o...  
Date: Fri, 14 Jun 2002 12:42:15 +0100 (BST) 
Subject: [usb] usb clarifications 

> 
> 
> 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@h...  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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