timer

代码说明：

  使用定时器TIM3输出四路的SPWM波，其中一二路、三四路波形一致，一二路与三四路波形相差180°(Timer TIM3 is used to output four SPWM waveforms, of which one, two, three and four waveforms are identical, and one, two and three and four waveforms are 180 degrees different.)

文件列表：

timer.c, 7415 , 2019-07-20