能够长生pwm方波，内容小巧精致，希望大家共同交流-Pwm square wave to longevity, as a small fine, hope that we share

飞思卡尔的PWM代码，通过改变PWM输出的占空比，可以做出特定频率的方波-Freescale s PWM code by changing the duty cycle of the PWM output, you can make a specific frequency square wave