On Wed, 13 Sep 2006, Phil Endecott wrote: > Dear USB Experts, > > Has anyone ever tried to couple a device controller (gadget) and a host > controller on the same processor to make a transparent feed-through USB > channel? If it were possible to do this then you could make a USB > analyser. I understand that both sets of code use the same data > structures, so how hard would it be?
You'd be surprised. > I have an NSLU2 (http://nslu2-linux.org/) which has an XScale USB > device controller (soldering needed to bring it out to a connector) and > an external host controller on its PCI bus. If these could be coupled > within the kernel as I have described then you could have a very > convenient pocket-sized USB debugging tool. > > Any thoughts? Other people have suggested this in the past. Unfortunately it can't be done. A USB bus analyzer needs to receive every packet on the bus, but a USB device controller will receive only packets addressed to itself. There are other technical reasons why this can't be made to work, such as the electrical constraints on voltage, current, and impedance in the USB signal lines. Alan Stern ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
