调节舵机使之转动5个角度 0 45 90 135 180 PWM信号周期为20ms。程序流程是：开机时舵机角度自动转为0度，按下 P3.7则转到45度，以后就根据两个按键的按下而转动。控制高电平的持续时间即可控制舵机停止制动的角度，0.5ms-0度 1-45 1.5-90 2-135 2.5-180 。-Adjust the steering gear so that rotation angle of 5 0 45 90 135 180 PWM signal period is 20ms. The program flow is: the power steering gear angle automatically be converted to 0 degrees, press the P3.7 go to 45 degrees, after the rotation according to the press of two buttons. Control the duration of the high you can control the angle of the steering gear to stop braking, 0.5ms-0 1-45 1.5-90 2-135 2.5-180.