2010/7/16 John Harrison <johnharrison...@gmail.com>: > Perhaps I am not reading the right parts of the documentation but I can't > figure out how to write to my device even given your hints about my device > not having endpoints. Frankly I don't even know what an endpoint is. I was > hoping not to have to know. :-) I just need to send some simple strings to > my device and get back some floats.
Getting PyUSB users talking to USB devices without USB knowledge is my ultimate goal, but it is harder to do than it sounds. I have some ideas for common cases which I intend to implement in the future. I don't know much of your device, but I guess you have to use ctrl_transfer to send and receive to/from it. The point is that control transfers are the most complicated type of transfer in the USB standard, because it is a structured transfer. Here is an example from my test firmware: import usb.core import usb.util dev = usb.core.find(idVendor=0xfffe) msg = 'test' bmRequestType = usb.util.build_request_type(usb.util.CTRL_OUT, usb.util.CTRL_TYPE_VENDOR, usb.util.CTRL_RECIPIENT_DEVICE) dev.ctrl_transfer(bmRequestType, CTRL_LOOPBACK_WRITE, 0, 0, msg) CTRL_LOOPBACK_WRITE is a private request that I implemented in the firmware. If I am right about your device, you will need to know from some kind of datesheet what requests your device implement. > > Also how can I issue my own GET_STRING request to get a description of a > serial number, for example? Actually, PyUSB will implement a get_string function in the near future, it is just not implemented right now (but 0.4 version does). You may implement it using ctrl_transfer method, as GET_STRING is nothing else than a kind of standard control request, but I think this is not related to your issue. > > On Fri, Jul 16, 2010 at 8:43 AM, Wander Lairson <wander.lair...@gmail.com> > wrote: >> >> 2010/7/16 John Harrison <johnharrison...@gmail.com>: >> > Running testlibusb-win.exe I see: >> > >> > DLL version: 1.2.0.0 >> > Driver version: 1.2.0.0 >> > >> > bus/device idVendor/idProduct >> > bus-0/\\.\libusb0-0002--0x09db-0x00f9 09DB/00F9 >> > - Manufacturer : Measurement Computing >> > - Product : USB-2001-TC >> > - Serial Number: 014F0F9C >> > wTotalLength: 18 >> > bNumInterfaces: 1 >> > bConfigurationValue: 1 >> > iConfiguration: 0 >> > bmAttributes: 80h >> > MaxPower: 250 >> > bInterfaceNumber: 0 >> > bAlternateSetting: 0 >> > bNumEndpoints: 0 >> > bInterfaceClass: 255 >> > bInterfaceSubClass: 255 >> > bInterfaceProtocol: 0 >> > iInterface: 0 >> > >> > The product and Manufacturer match the device I am trying to communicate >> > with. BTW these values seem different with pyUSB. For example >> > >> > dev = usb.core.find(idVendor=0x09db, idProduct=0x00f9) >> > dev.iSerialNumber >> > >> > returns the value 3. >> >> I guess testlibusb-win issues a GET_STRING request over the value 3 to >> get a description of the serial number. Therefore it is ok. >> Now backing to your original problem, your device doesn't have any >> endpoints, this is because find_descriptor returned None and the >> assertion failed. Maybe your device only talks through endpoint 0 (a >> control endpoint that is kind of built-in). >> >> > >> > -John >> > >> > On Thu, Jul 15, 2010 at 6:02 PM, Xiaofan Chen <xiaof...@gmail.com> >> > wrote: >> >> >> >> On Fri, Jul 16, 2010 at 2:12 AM, Wander Lairson >> >> <wander.lair...@gmail.com> wrote: >> >> > 2010/7/15 John Harrison <johnharrison...@gmail.com>: >> >> >> libusb-win32-bin-1.2.0.0\bin\x86>testlibusb.exe >> >> >> Dev #0: 0000 - 0000 >> >> >> Dev #2: Measurement Computing - USB-2001-TC >> >> >> >> >> >> Dev #2 is the correct name for my device. >> >> > >> >> > Oh, sorry, I mentioned the wrong test app. I don't remember its name >> >> > and I don't have an Windows machine right now, but I mean the test >> >> > application with graphical interface, which dumps all device >> >> > descriptors... >> >> >> >> testlibusb-win.exe >> >> >> >> To John: >> >> >> >> +++++++++++++ >> >> http://sourceforge.net/apps/trac/libusb-win32/wiki >> >> Please describe your problems and your system as precise as possible >> >> (OS, service packs, version of libusb-win32, type of device, output of >> >> "testlibusb-win.exe", etc.). This will make solving problems a lot >> >> easier. >> >> +++++++++++++ >> >> >> >> BTW, if you have not done so, please update to libusb-win32 1.2.0.0. >> >> >> >> -- >> >> Xiaofan http://sourceforge.net/projects/libusb-win32/ >> >> >> >> >> >> >> >> ------------------------------------------------------------------------------ >> >> This SF.net email is sponsored by Sprint >> >> What will you do first with EVO, the first 4G phone? >> >> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first >> >> _______________________________________________ >> >> pyusb-users mailing list >> >> pyusb-users@lists.sourceforge.net >> >> https://lists.sourceforge.net/lists/listinfo/pyusb-users >> > >> > >> > >> > >> > ------------------------------------------------------------------------------ >> > This SF.net email is sponsored by Sprint >> > What will you do first with EVO, the first 4G phone? >> > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first >> > _______________________________________________ >> > pyusb-users mailing list >> > pyusb-users@lists.sourceforge.net >> > https://lists.sourceforge.net/lists/listinfo/pyusb-users >> > >> > >> >> >> >> -- >> Best Regards, >> Wander Lairson Costa >> >> >> ------------------------------------------------------------------------------ >> This SF.net email is sponsored by Sprint >> What will you do first with EVO, the first 4G phone? >> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first >> _______________________________________________ >> pyusb-users mailing list >> pyusb-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/pyusb-users > > > > -- > John > http://alumni.media.mit.edu/~harrison/ > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Sprint > What will you do first with EVO, the first 4G phone? > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > _______________________________________________ > pyusb-users mailing list > pyusb-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/pyusb-users > > -- Best Regards, Wander Lairson Costa ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? 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