Tutorial: USB Control Transfers with LUFA

[Christoph Redecker]

Hi folks,

I've written a tutorial about USB control transfers with LUFA, based on
a recent thread [1] and with some help from Dean. Here it is:

http://www.avrbeginners.net/new/tutorials/usb-control-transfers-with-lufa/

If you like to, please give me feedback on content, typos, grammar -
anything that needs correction!

Regards

Christoph

[1]
http://groups.google.com/group/lufa-support/browse_thread/thread/310876351f413206/

[Christoph Redecker]

Hi list,

I updated the control transfers tutorial, which can be found here:

http://www.avrbeginners.net/new/tutorials/usb-control-transfers-with-lufa/

Cheers

Christoph

[Dean Camera]

Christoph,

I put a link to it in the LUFA documentation (see http://fourwalledcubicle.com/files/temp/LUFA-Doc-NEXT/Documentation/html/_page__resources.html#Sec_UnofficialResources for a preview) which will be available in the next release, due soon. I also just put it in my Twitter feed, in case anyone there is interested in it that isn't already subscribed to the support list.

Great work!

- Dean

[Christoph Redecker]

Oh that's cool! Thank you for both the link and the tweet.

Christoph

> <http://www.avrbeginners.net/new/tutorials/usb-control-transfers-with-lufa/>
>
>
> Cheers
>
> Christoph
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[Christoph Redecker]

I got off-list feedback regarding request filtering. I'm filtering the
request type for class-specific requests using the REQTYPE_CLASS mask in
the tutorial.

The suggestion is to use REQTYPE_VENDOR in order to make it possible to
use a standard class and enhance it with custom control transfers. That
way it could be possible to implement a CDC device with (sticking to the
tutorial example) an integrated servo controller *if* the OS doesn't
prevent us from doing such a thing.

Is there any "best practice" regarding this?

Regards

Christoph

[Chris McClelland]

I was under the impression that a device that is claimed by a class
driver (mass-storage, CDC, HID etc) cannot also be claimed by a vendor
driver.


On May 20, 9:31 pm, Christoph Redecker <redec...@avrbeginners.net>
wrote:

[Donald Delmar Davis]

I have done this with osx and libusb. Linux requires you to unload the driver or write a modified driver.

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[Christoph Redecker]

USB devices with device class 0xFF or interface class 0xFF are called
"vendor specific" by the USB specification. There is no class
specification for homegrown devices (how could there be one, anyway), so
that's +1 for using vendor specific requests.

I think I'll change that next time I udpate the tutorial.

Regards

Christoph