Date: Fri, 28 Jun 2002 07:51:36 +0000
From: "neil barnes" <[EMAIL PROTECTED]>
Subject: Re: [LIB] L50 & USB?


>Date: Fri, 28 Jun 2002 02:26:51 -0500
>From: John Musielewicz <[EMAIL PROTECTED]>
>Subject: Re: [LIB] L50 & USB?
>
>On Thu, 27 Jun 2002 22:50:24 -0700, you wrote:
>
> >Date: Fri, 28 Jun 2002 05:44:58 +0000
> >From: "neil barnes" <[EMAIL PROTECTED]>

> >I suspect the timing requirements for USB are not meetable.
>
>Are you saying  the minimum data speeds are hardwired and it only
>sends and recieves at those speeds and the usb controller  will stop
>and give you an error if its not transmitting fast enough? That would
>be a problem and make usb a really inflexible method of a data
>interface. If all a person wanted was a usb-like interface with the
>same pinout, so it can be used with any usb equipped laptop, and
>wanted to use it as something like a programming interface speeds
>become much less revelant. Plus since many micro controllers use 8 and
>16 bits  busses it couldn't be used with those. I guess serial will
>live on.

Tell you the truth, I haven't investigated in detail. There are three speeds 
defined for USB2 - 1.5, 12, and 480Mb/s - only one of which is capable of 
being handled by 16-bit pcmcia if the data is coming continuously. I guess 
if the device isn't capable of handling all the modes - e.g. high speed 
isosynchronous continuous data - then it doesn't qualify as USB. Hence, no 
logo, hence no parts.

If you have a couple of hours to kill, the full specification is online at 
www.usb.org

Neil


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