On Fri, 27 Jul 2007, Gabriel Maganis wrote:

> Hello Alan,
>    I guess I'm trying to bypass the code that makes it so it can't
> possibly work. I'm trying not to say what it is I'm trying to do in
> general I guess :). But I really would just like to be able to send
> that packet. Would you know if the code I might look at is in usbcore
> or should I look at the HCD code? I've tried grepping around quite a
> bit but I'm not sure what it is really I should look for.

It isn't code at all -- it won't work because of the hardware!

The low-speed keyboard's USB interface hardware is looking for signals 
at 1.5 MHz.  If the computer starts sending full-speed data, it will be 
modulated at 12 MHz.  Furthermore, at low-speed a 0 is indicated by a 
high voltage on the D- line whereas at full-speed a 0 is indicated by a 
high voltage on the D+ line.  (Or maybe I have them reversed, but one 
is definitely the opposite of the other.)

The keyboard's hardware can't possible cope with that.

Alan Stern


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel

Reply via email to