Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you may not be able to execute some actions.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
插上蜂鸣器会滋滋响是什么原因
如果是有源蜂鸣器，控制IO电平高或者底。 如果是无源蜂鸣器，控制IO输出PWM。