code: def read_pins
        p = FFI::MemoryPointer.new(:uchar, 1)
        check_result(Ftdi.ftdi_read_pins(ctx, p))
        p.read_uchar
      end
docs: Directly read pin state, circumventing the read buffer. Useful for bitbang mode.
   @return [Fixnum] Pins state
   @raise [StatusCodeError] libftdi reports error.
   @see #set_bitmode