Thanks a lot, both of you. I am not disappointed in the sense that I got very informative advance. Will seek other solution to my need. Yuyang -----Original Message----- From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] Sent: Thursday, January 24, 2013 2:15 PM To: Du, Yuyang Cc: linux-usb@xxxxxxxxxxxxxxx Subject: Re: USB host port acts like a signal generator On Thu, Jan 24, 2013 at 02:44:44AM +0000, Du, Yuyang wrote: > Hi, > > My intent is really special, I don't know whether I missed something, > but all the articles about writing a USB driver do not address my > need. > > I want to use the USB port on the host as a signal generator to drive > a USB cable (the two data lines) connected to another device's USB > connector. The generator just needs to output 1 or 0 (high or low > signal) as controlled by a user space program. That is impossible to do, sorry. Please read the USB specification (usb.org) if you are curious as to why this is. sorry, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
