>From: "Maulik Mankad" <[EMAIL PROTECTED]> Date: Thu, 22 Jun 2006 >13:43:32 -0700 > > >Hi Alan and David, > >First of all let me thank both of you for replying to my mail. > >This is what the datasheet of Intel's IXP465 say for the Embedded TT. > >"IXP465 USB host supports directly connected full and low speed devices >without requiring a companion controller by including the capabilities of a >USB 2.0 high-speed hub transaction >translator. Although there is no separate Transaction Translator block in >the system, the transaction translator function normally associated with a >high-speed hub has been implemented within the DMA and Protocol engine >blocks. The embedded transaction translator function is an extension to >EHCI >interface, but makes use of the standard data structures and operational >models that exist in the EHCI specification to support full and low speed >devices." > >(1) Can there be a problem in the DMA engine, which is not transmitting my >descriptor requests to the device? I do not have any programmable register >to start the DMA or to initialize it. > >Alan- >============ >About Bus trace. >============ >I use the Ellisys USB analyzer (hardware) to capture the USB packets on the >bus. The analyzer shows the following packets. >-> Reset >-> High Speed Detection Handshake (Timeout) [The device properly generates >the High Speed Chirp but no response from host, as the host does not >support >High Speed] >-> SOF packets. >-> Suspended State > >At this point as per the bus enumeration sequence I should get the Device >Descriptor request on the bus. The USB analyzer does not capture this >request. Moreover I have traced the Linux core code for the USB and it >seems >that the request gets timed out and then aborted and removed from the >queue. >This is why I believe its not captured by the analyzer. >
Are you sure that whatever device you have connected has a pullup resistor on D+ (for full speed device), after the chirp. It looks like the device thinks it is high speed, while the host is in full speed? The device is seen originally or the host would not reset the bus. Then the host starts SOFs and looks like it no longer sees the pullup and then quits talking to an empty bus before it even gets to enumeration. Things to try: another device another cable no analyzer in the circuit. Good luck, Steve 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-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
