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usbreq.py — a USB library for humans

usbreq is a WIP simple helper Python module for quick scripts and tests with USB devices. It is not intended for stable programs.

Usage

The core of this library is the USBDevice class, which wraps PyUSB's usb.core.Device class, and adds additional shortcut methods (currently only two):

  • USBDevice.control_request(self, *, direction, req_type, recipient, request, value, index, length, data)
    • direction, req_type, recipient, and request are accepted as strings (in any case), integers, or instances of usbreq's relevant enums (e.g. req_type=usbreq.USBRequestType.STANDARD).
    • The fields of bmRequestType (direction, req_type, and recipient) when given as integers are accepted either bitshifted or not.
    • For accepting request as a string, currently all standard requests of all recipients are implemented, but class requests are not yet.
    • data cannot be specified for IN requests
    • length is optional and inferred from data for OUT requests, or set to maximum (0xFF) for IN requests.
      • If specified for OUT requests, only the specified amount of data will be sent to the device.
  • USBDevice.get_descriptor(self, *, type, index, langid=None, length, find_intended=False)
    • type is accepted as a string (in any case), an int, or an instance of usbreq.USBDescriptorType.
    • index is optional and defaults to 0.
    • langid only makes sense if type="string", and is optional there as well (defaults to 0)
    • length is passed through directly to USBDevice.control_request()
    • find_intended=True asks this method to "cheat" for you and find a descriptor that is not directly requestable in USB, by parsing data for you. For example: get_descriptor(type="endpoint", index=1, find_intended=True) will first request the device's configuration descriptor, and then parse its subordinate descriptors to find the the second (zero-indexed) descriptor where bDescriptorType is 0x05.

Documentation

Usage examples pending, but API documentation is live on RTD.