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/* Synchronize, decode and check USB frames */
One time sample is done, it is not readable. In fact USB frames are synchronized (they started with a certain synchronization pattern), encoded (NRZI), and checked (CRC). CRC type depends on frame length. Encoding is done for synchronization optimization.
Then using USB HID manual, you can understand type of frames, and author of them, and remark that the author alternatealternates: USB master (PC) or USB slave (joystick)
You can use some "USB sniffer software" in order to understand more easily some frames contain, but they generally don't give all frame, and full frame.
