Hello! I investigated the setup again at last weekend.
Somebody on linux-usb Mailinglist explaind the "failed with status 500000" message. And so i decided to check the waveforms on D+ and D-. I've discovered that there is a complete impedance missmatch between the ds2490 and the usb-port of this laptop. In the datasheet from dallas there are 30pF capacitors recomended on D+ and D-. But on the Notebook side there are at least 300pf expected. So i have added capacitors to my circuit at D+ and D- and everything works well now. The +5V Power Supply on the Notebook (and all other USB hosts reachable) is turned on as soon as the notebook is powered up. > USB Power is usually switched, besides from non-standard ports on certain > desktop mainboards. The capacitors are *not* loaded as soon as you plug in > the device in that case. > > As soon the host controller detects the device speed resistor -- the 1.5k > resistor between D+ and +5V if you built your adapter as the DS2490 data > sheet suggests -- it reports that incident to the driver and the USB host > controller driver turns on power for that port (or not, if no driver is > loaded). Wouldn't this be a chicken and egg problem? The 1.5k resistor couldn't be detected if the +5V power isn't turned on. And the +5V power wouldn't be turnd on if the 1.5k resistor isn't detected..... > saving issues. E.g. a laptop could turn off all USB devices but an external > USB keyboard or card reader during STR state. Yes, but i think this is done by putting the devices into power saving mode and not by turning off the +5V USB supply. It's done in the same manner with the ds2490. Kind regards, Klaus ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
