主函数不停的查询 ADXL345的转换结果，得到x、y和 z三个方向的加速度值（读数值），然后将其转换为与自然系坐标的角度，并将结果在 LCD 模块上显示出来。DS0 来指示程序正在运行，通过按下WK_UP按键，可以进行ADXL345 的自动校准（DS1用于提示正在校准）。(The main function continues to query the transformation results of ADXL345, and obtains the acceleration values (read values) in the three directions of X, y and Z, and then converts them to the angle of the natural system coordinates, and the results are displayed on the LCD module. DS0 indicates that the program is running. By pressing the WK_UP button, ADXL345 can be automatically calibrated (DS1 is used for prompting is being calibrated).)