OPENCORES.ORG

From: Virendra <virendradhavale@y...>

Hi Virendra,
The picture that i see as a USB host is  HOST --> PHY ---> USB BUS.
In this case if the PHY is UTMI, the host has to just keep it in high speed 
mode with a proper
combination of xcvr_select and termselect signal. I actually dont remember, 
but from what i
remember both should be tied to ground.(just incase check with UTMI spec). 
When the host
ties both those signal to ground, the PHY just activates its pulldown 
resistors( 15k to both D+
and D-) thereby bringing down the USB bus to SE0 state.

On seeing xcvr select and termselect activating high speed, the default 
state of the USB bus
for high speed is SE0, therefore the transceiver reflects this default state 
in the line state.

I hope this clarifies your query.

Regards,
Ravi Rajaraman

>From: Virendra <virendradhavale@y...>
>Reply-To: virendradhavale@y...,   "Discussion list about free,open 
>source USB IP core" <usb@o...>
>To: usb opencores <usb@o...>
>Subject: [usb] Driven SE 0
>Date: Mon, 29 Nov 2004 09:42:37 +0000 (GMT)
>
>I would like to know as to how does the USB host drive SE 0 on the bus. I 
>mean the exact events those happen during driven SE 0. I also want to know 
>as to how the UTMI responds to generate SE 0 on its LineState signal.
>
>Regards,
>
>Virendra.
>
>Yahoo! India Matrimony: Find your partner online.
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