On Tue, Nov 23, 2010 at 12:33 PM, Andrew Errington <a.erring...@lancaster.ac.uk> wrote: > Hello everyone, > > I have had some success with PyUSB, but it's all new to me and I am struggling > with something which should be simple. I am using PyUSB v1.0. > > I am trying to write to the GPIO pins on a USB sound interface. I have one of > the extremely common USB sound dongles which contains a 3S SSS1623 chip. > This chip has two GPIO pins, and inputs for buttons (volume up/down, mic. > mute and speaker mute). I have the datasheet for the 3S chip which shows me > the pins for GPIO, but it doesn't tell me the HID commands. > > Another common device is the C-Media CM108 chip, which has four GPIO pins. > The C-Media chip is compatible (but not identical) and I have the datasheet > for this too, with pinouts *and* HID commands. > > So far I have written a simple PyUSB script which identifies the 3S chip, > detaches the HID interface, and loops around continuously reporting the > button states and GPIO states. I used the C-Media HID 'read' documentation > to decode what the 3S chip reports, and it matches. Next I want to write > four bytes to set GPIO0 to ouput, and drive it high or low. I am using the > C-Media 'write' documentation, but it's not working. The documentation might > be incompatible with the 3S chip, or I may have made a stupid mistake. >
Without looking at your codes, I think you will have to use reverse engineering to get things work. pyusb/libusb is just a tool and you will have to figure how the device works. Apparently the two device are not that identical and your tests have already show that they are different. -- Xiaofan ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ pyusb-users mailing list pyusb-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pyusb-users
