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Message
From: "kw@nie" <kwanie@p...>
Date: Thu, 3 Jan 2002 10:43:11 +0800
Subject: Re: [usb] CYPRESS EZ-USB, not so EZ just confusing
Hi Justin,
When a USB device is plug in, either D- (low speed), D+ (full speed) or both
(high speed) will be pulled high. This lets the host PC knows that a device
has been attached and what speed to communicate with it. During enumeration
the host will collect the device's information and check if the appropriate
driver has already been installed, otherwise host will search for the driver
and install it (e.g. Windows will look inside C:\WINDOWS\INF for an .inf
that matches). In the event that a suitable driver cannot be found then the
host will require the user to provide the driver.
I haven't personally used the EZ-USB, but I was looking at it for a project
previously. If I recall correctly, EZ-USB is defaulted as 'Firmware Update
Sub-Class' device. When you first plug in the EZ-USB it will report itself
as a 'Firmware Update Sub-Class' device, this should load the class driver
for the 'Firmware Update Sub-Class' and your firmware is downloaded to the
EZ-USB. After downloading it will re-enumaerate and this time round your
firmware is to report the device infomation of your own so that your own
driver can be loaded.
Cheers,
kwanie
----- Original Message -----
From: <pueet@h...>
To: <usb@o...>
Sent: Thursday, January 03, 2002 12:08 AM
Subject: [usb] CYPRESS EZ-USB, not so EZ just confusing
> Hello Everyone, thank you so much for taking a look at this. i just had
> this project dumped on me and now I'm totally confused. we purshased
> some Cypress EZ-USB chips and I'm very new at this stuff. what I need
> to acomplish is to be able to plug in this chip into any USB on any
> computer that has the proper program on it, that we have to write, and
> it will recginize the chip and be ready to run the software. so where I'm
> stumped is the very begining how does the PC know when it is pluged in
> and how does the driver get installed. we also got a Development board
> with the chip on it already and when i first pluged it in with out me
doing
> a thing it was installed. how do i get ours that stands alone to do that.
> I guess MY BIGGEST PROBLEM RIGHT NOW is how do i communicate with
> it? how do i wirte a basic program to tell it to read a port or something
> simple like that? IF there is anyone out there that can help me out i
> would greatly aperciate it. Thank you so much for listening to me
> ramble. Have a great New Year!
> Thanks again,
> Justin
>
>
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