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Re: USB Enumeration problem

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      02-24-2010, 09:14 AM
On Feb 23, 11:54*pm, Joe Chisolm <(E-Mail Removed)> wrote:
> mikecw_1968 wrote:
> > I have a USB device (development board with firmware) that I connect to
> > using Hyperterminal (or Tera Term). *When I power the device, connectit to
> > the PC and bring up Hyperterminal, all is good. *It enumerates and I can
> > connect.

> > At this point, if I cycle power on the device, after it comes up
> > Hyperterminal will not communicate. *I then kill Hyperterminal and bring it
> > back up but the COM port that was enumerated earlier is no longer in the
> > list of valid ports. *

> > At this point, I disconnect Hyperterminal, cycle power on the device then
> > reconnect. *All is well.

> > What am I not understanding about the USB initialization/enumeration
> > sequence?

> > Btw, the PC is running Windows XP.

> > Thanks.

> > --------------------------------------- * * * * * *
> > Posted through

> Is your device using a CDC-ACM stack? *If so, I had the same problem.
> It is not a enumeration problem but a Windows problem. *If you hook the
> device to a Linux box with CDC-ACM support and use minicom, every thing
> will probably work fine. *It has something to do with the way
> windows deals with USB serial.
> --
> Joe Chisolm
> Marble Falls, Tx.

There are some fixes around for this and involves WinXP SP3
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