OPENCORES.ORG

From: "Marc Reinig" <mreinig@p...>

According to the point :* The host can terminate a setup request before you have sent all that it
asked for.  It will do this by sending status or a new Setup.

Can i ask how should i treat the request in the setup stage if the host terminate it without entering status stage. For example , the host send me a setup commanding "Set_Address" or "Set_Configuration" , but then the host send me another setup token requesting another command instead of sending me a IN token for a Status stage. Should i still set myself a new address or new configured value in this case ? or should i treat the request terminated and doing nothing ?

Also , if the host send me a reset after i have got a new address , should my device start from the beginning and listen to address 0 again ?

Thank you very much for your listening .

Regards,
TOM

>From: "Marc Reinig" <mreinig@p...>
>Reply-To: "Discussion list about free,open source USB IP core" <usb@o...>
>To: "Discussion list about free,open source USB IP core" <usb@o...>
>Subject: RE: [usb] some question abotu USB
>Date: Fri, 5 Mar 2004 06:10:09 -0800
>
>There is no defined sequence for a host to enumerate a device.  It varies
>from OS to OS and release to release.  The key to success is to do whatever
>the host asks and make sure your response complies with the spec.  Do not
>rely on any particular sequence.
>
>Things to watch for:
>
>* The host will often ask for more than you have got.  Reply only with what
>you have, never more.
>
>* The host can terminate a setup request before you have sent all that it
>asked for.  It will do this by sending status or a new Setup.
>
>* The host will often ask for less than you have.  Make sure you only send
>what it asks for.
>
>* After the host sends a Set Address, make sure you are listening on the new
>address.  But, don't do this until after the end of the status phase.  This
>is the only Setup where you don't complete the request until after status.
>All other you complete the request and then enter the status phase.
>
>Marc Reinig
>System Solutions
>Windows Driver and Embedded Product Consulting
>
> > -----Original Message-----
> > From: KO TOM [mailto:tomko81@h...]
> > Sent: Thursday, March 04, 2004 6:26 PM
> > To: mreinig@p...; tomko81@h...
> > Subject: RE: [usb] some question abotu USB
> >
> >
> > Dear Marc,
> >
> > Thx for your reply, however , i do confused about the process of
> > enumeration of USB device.
> >
> > I have read some books and documentation talking about the
> > enumeration process, the steps are:
> >
> > 1. host - > reset
> > 2. host  -> request for device descriptors by default address 0
> > 3. device  -> responding with first 8 bytes of device descriptor
> > 4. host -> reset
> > 5. host -> set new address for device
> > 6. host -> request for device descriptors with new address
> > 7. device  -> responding with all 18 bytes of device descriptor
> > 8.host -> get configuration from device
> > 9.host -> set configuration to device
> >
> > Is the above steps correct for USB enumeration?  Is that OS will
> > appear a "find new hardware" window after the above steps ? Any
> > more reset step i have missed above?
> >
> > What I am confused is step 2 the first time host ask for descriptor:
> > Will the host actually ask for 8 bytes of descriptor( the host
> > should send out 80 06 00 01 00 00 08 00) or the host is actually
> > asking for 18 bytes ( the host should send out 80 06 00 01 00 00
> > 12 00) but we just return it with first 8 bytes?
> > If we are returning 8 bytes descriptor, what should be the value
> > of  first byte of descriptor we return? 12H or 08H?
> >
> > In my mind, i guess the default max packet size should be 8
> > before the host get our descriptor, so device can only send data
> > packet with 8 bytes in step 2 but can return the whole descriptor
> > ( 18 bytes) in a single packet in step 7.
> > Am my guess right ?
> >
> >
> > Also , USB1.1 and USB 2.0 are using the same hardware interface ,
> > when the device is plugged into the usb bus, how can the host
> > know it is running at 1.1 speed or 2.0 speed? (i mean slow, full
> > and high speed in usb).
> >
> >
> > Sorry for asking so much question, I am looking forward to
> > hearing from you.
> >
> >
> > Regards,
> > TOM
> >
> >
> > >From: "Marc Reinig" <mreinig@p...>
> > >Reply-To: "Discussion list about free,open source USB IP core"
> > <usb@o...>
> > >To: "Discussion list about free,open source USB IP core"
> > <usb@o...>
> > >Subject: RE: [usb] some question abotu USB
> > >Date: Thu, 4 Mar 2004 07:32:19 -0800
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > [mailto:usb-bounces@o...]On Behalf Of KO TOM
> > > > Subject: [usb] some question abotu USB
> > >
> > > > 1.  Is that only endpoint 0 can be a inout endpoint ?
> > >
> > >An endpoint is the concatenation of the endpoint number and it's
> > direction.
> > >So, there can be two endpoints associated with a given endpoint
> > number (an
> > >In endpoint and an out endpoint).  When an endpoint is defined
> > as an IN/OUT
> > >endpoint, it is really a pair of endpoints that share a common endpoint
> > >number.  So, it is kind of a misnomer.  However, since in common
> > practice,
> > >there is only one IN/OUT endpoint and that is the control
> > endpoint, we just
> > >call it endpoint 0, when technically we should call it the
> > IN/OUT endpoint
> > >pair of control endpoint number 0.
> > >
> > >So, no, any endpoint number can be an IN/OUT endpoint.  However, I have
> > >never seen any device with more than one control endpoint.
> > >
> > > > 2.  If some of the endpoint , like endpoint 2, is using control
> > > > transfer . Can it be an inout endpoint ?
> > >
> > >It could, but why would you do this?
> > >
> > > > 3. Due to the tree architecture of USB, is that my device can
> > > > recieve any packet on the usb bus ? I mean can my device (address
> > > > 3)receive the packets sending to other device (address 2) ? Is
> > > > that all packets are boardcasting?
> > >
> > >You will see all packets from the host, and none from other devices.
>
>
>_______________________________________________
>http://www.opencores.org/mailman/listinfo/usb

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