Stuart Stevenson wrote: >Gentlemen, > Realizing I will be corrected if I am wrong I will state this anyway. > I believe we are mixing two different issues in this thread. > >ONE, > The use of the USB interface in the real time control path > >TWO, > The use of the USB interface in the HMI path > > Good point. There may be some confusion going on there, but RT command/control isn't the only problem with USB.
>>From what I read the USB interface is not developed to the point of >usability in the real time deterministic control protocol. > >>From my personal experience the USB interface can be used for data >transfer, keyboard and mouse communications, joypad communications. >The USB interface can probably be used for any other 'user space' >'non-real time' communications. > > Except that some people have reported "bumps" or unexpected realtime delays when they plug in USB storage devices. I don't think we've collected enough data points to be able to identify whether it's one specific type of flash, only some manufacturer, a USB controller type, or a problem endemic to USB regardless of all the other variables. Personally, I suspect that the plugging event kicks off re-enumeration of the USB bus, which wants to happen more or less atomically, but I don't have any evidence to prove it :) - Steve ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
