在一般MCU都没有自带PWM模块，必须通过定时器产生。虽然能够实现这个PWM，但是需要以浪费宝贵的定时器为前提。本例采用ＳＴＣ12C些列单片机的两路PWM模块产生两路PWM，占空比从0 --99 -In general, do not bring their own low-end MCU PWM module, must be the timer. Although able to achieve this PWM, but need to waste valuable timer as a