PWM产生杂波，请问是什么原因？

homo · 发表于 2015-6-5 13:11:41

利用定时器2配置双通道输出，分别为PA0和PA1，配置代码如下，发现PA0输出正常，PA1，有很多杂波，请问一下是什么原因？
void TIM2_PWM_Init(u32 arr,u32 psc)
{

GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_TIM2);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_TIM2);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA,&GPIO_InitStructure);

TIM_TimeBaseStructure.TIM_Prescaler=psc;
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period=arr;
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);

//??????TIM2 Channel1 PWM????
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;

TIM_OC1Init(TIM2, &TIM_OCInitStructure);
TIM_OC2Init(TIM2, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);
TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM2,ENABLE);

TIM_Cmd(TIM2, ENABLE);

}
逻辑分析仪输出的结果如下：