程序演示了如何用普通定时期产生3 路相同周期，不同占空比的PWM 波。

TIMXCLK的时钟是36MHz，分频系数是0，所以 TIM3计数的频率是36MHz。-Program demonstrates how to generate three times the ordinary way given the same period, the duty cycle of the PWM wave different. TIMXCLK clock is 36MHz, frequency coefficient is 0, so the frequency is TIM3 count 36MHz.