编制程序改变0832输出经放大后的方波信号的占空比来控制电机转速。本实验中D/A输出为双极性输出，因此电机可以正反向旋转。-Programmed to change the 0832 output by the amplification of the duty cycle square wave signal to control motor speed. This experiment D/A output for bipolar output, it can be both positive and negative to the rotary motor.