Usb Standard interfaces?

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Pete Eddy

Usb Standard interfaces?

Post by Pete Eddy » Wed Apr 24, 2002 3:33 pm

Ok every body and his brother is making a "USB enabled" device today.
Are there any standards for talking to a particular class of device? For
example if you wanted to experiement with using a USB webcam or Digital
camera in a QNX app is there a common interface used by the industry or do
you have to write vendor specific code for each device? What about the
other billion different USB devices?

Pete Eddy

Phil Olynyk

Re: Usb Standard interfaces?

Post by Phil Olynyk » Sat Apr 27, 2002 2:19 am

Hi Pete -
If you go www.usb.org and poke about, you will find documentation for
many different classes of device, from printers to audio to bulk, not to
mention the Human Interface Device class - and even a specification of
how class specifications should be written....including the relevant
#defines for each class.
If you go out and buy almost any device, bring it home and plug it in
to your RTP computer, and then run usb -vvv, the odds are pretty good
that you will find the class is "Vendor defined" - even if the device
really does follow the proper class specification otherwise!
I have had some luck in using the Linux drivers as documentation
sources, although now I know more about the Linux usb stack than I
really wanted to know....

Phil Olynyk
OBT Software Corp


Pete Eddy wrote:
Ok every body and his brother is making a "USB enabled" device today.
Are there any standards for talking to a particular class of device? For
example if you wanted to experiement with using a USB webcam or Digital
camera in a QNX app is there a common interface used by the industry or do
you have to write vendor specific code for each device? What about the
other billion different USB devices?

Pete Eddy

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