Tom Schouten wrote: > dh = dev.open() This opens the device.
> dh.claimInterface(0) # -> usb.USBError: could not claim interface 0: Device > or resource busy This tries to claim the interface which is already claimed by usb-serial. > dh.controlMsg(1,1,[0,0,0,0]) This performs a control request over the default endpoint, which doesn't belong to any interface at all. >>> It seems plausible a USB device can only be opened once, >> >> That's not the case however. > > I see. I'm confusing device and interface. Yes. > So basically, I would add another interface to the USB firmware, > which then can be claimed by a different process. You can do control requests without having claimed any interface. If you add an interface then it might actually work on Windows too, but I'm not sure. //Peter
