stm32f103发PWM遇到问题，求帮助

csyou_kiko

 用一个TIM发相位相差180度、占空比小于50%的两路PWM用于驱动推挽变换器，但是每次复位之后都会有一个脉冲，不知道是怎么来的。如图

这个是软启动时的

还有启动时没有开TIM时的波形

我的配置如下
 
void TIM4_Configuration(void)
{
        TIM_TimeBaseInitTypeDef TIM_TBInitStructure;
        TIM_OCInitTypeDef TIM_OCInitStructure;
        uint16_t PrescalerValue = 0;
        PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
        TIM_TBInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
        TIM_TBInitStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned1;
        TIM_TBInitStructure.TIM_Period = 1200; //10kHz Equal to 20kHz for push-pull
        TIM_TBInitStructure.TIM_Prescaler = PrescalerValue;
        TIM_TBInitStructure.TIM_RepetitionCounter = 1;
        TIM_TimeBaseInit(TIM4, &TIM_TBInitStructure);
        TIM_PrescalerConfig(TIM4, PrescalerValue, TIM_PSCReloadMode_Immediate);       
 
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
          TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
          TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
        TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
        TIM_OCInitStructure.TIM_Pulse = 60;
        TIM_OC3Init(TIM4, &TIM_OCInitStructure);
        TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
 
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
          TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
          TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
        TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
        TIM_OCInitStructure.TIM_Pulse = 1140;
        TIM_OC4Init(TIM4, &TIM_OCInitStructure);
        TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);
 
        TIM_ARRPreloadConfig(TIM4, ENABLE);
        TIM_SetCounter(TIM4, 600);
        TIM_ClearFlag(TIM4, TIM_FLAG_CC3| TIM_FLAG_CC4);
 
        TIM_ITConfig(TIM4, TIM_IT_CC4, ENABLE);
        TIM_Cmd(TIM4, ENABLE);
}
是配置有问题么？怎么才能解决呢？谢谢各位啦！
 

安

看配置没有问题，建议仿真一下配置过程，到底是看看是哪儿引起的脉冲输出。

csyou_kiko

回复第 2 楼 于2013-05-09 00:12:22发表:
看配置没有问题，建议仿真一下配置过程，到底是看看是哪儿引起的脉冲输出。
问题已解决，只要将timer寄存器赋600那句放在配置OC寄存器之前就行了。谢谢您的建议！