On Fri, 13 Oct 2006, Rao, Shalini Gangadhara wrote: > Hi Greg, > > When my custom made board acting as a Mass storage device is connected > to a Host directly it was not working. But when the same board was > connected to the host via a bus powered hub, it was working fine. > > When I took the trace of the data going on the bus, I could see that > Host sends setup packet. This is followed by the request. After > receiving this request on the device, the device acks the host. I could > see this ack from the CATC trace. After this there was no IN token from > the host to receive the response from the device for the > get_device_descriptor request. > > As there was no IN token from the Host I presume that the IN token has
You must mean the ACK token. > not reached the Host due to which it is not sending the next IN token. I > doubt that the signal level is not enough for the host to accept the > ack. But the same ack is recognized by HUB and the CATC analyzer. > > Is my understanding correct? What might be the probable cause of the > issue? Possible cause: The 480 MHz clock driving the signals on your device's USB interface isn't set to quite the right frequency. Consequently the host's EHCI controller doesn't receive the bits correctly. The powered hub and the CATC analyzer are more forgiving, and the hub reclocks the bits so that the host is able to receive them. 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 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
