这几天闲来无事弄磁悬浮，顺便学习下PWM的控制，为以后的SPWM学习铺路。碰见如下问题TIM1_CH1 的幅值 是3.3V  而我镜像配置的TIM1_CH2只有0.3V
我看见贴吧好像有人碰到这个问题，但是没有正确答案，希望能够正确的解决，帮助到有需求的人。

PWM2 PWM1

前面是TIM1_CH2的波形，后面是TIM1_CH1的波形

代码如下

static void TIM1_PWM_2load_Init(uint16_t arr,uint16_t  psc)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    TIM_OCInitTypeDef    TIM_OCInitStructure;

     RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO|RCC_APB2Periph_TIM1,ENABLE);

    GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_8|GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.Speed = GPIO_Speed_50MHZ;
    GPIO_Iint(GPIOA，&GPIO_InitStructure);

    TIM_TimeBaseStructure.TIM_Period = arr;
    TIM_TimeBaseStructure.TIM_Prescaler =psc;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TImeBaseInit(TIM1,&TIM_TimeBaseStructure);

   TIM_OCInitStructure.TIM_OCMode =TIM_OCMode_PWM2;
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
   TIM_OC1Init(TIM1,&TIM_OCInitStructure);
   TIM_OC2Init(TIM1,&TIM_OCInitStructure);

    TIM_CtrlPWMOutputs(TIM1,ENABLE);

    TIM_OC1PreloadConfig(TIM1,TIM_OCPreload_Enable);
    TIM_OC2PreloadConfig(TIM1,TIM_OCPreload_Enable);

    TIM_ARRPreloadConfig(TIM1,ENABLE);
    TIM_Cmd(TIM1,ENABLE)

}

void PWM_Init(void)
{
    TIM1_PWM_2load_Init(899,0);
}

void PWM_Breath(void)
{
    static uint8_t flag=0;
    static  uint16_t  pwmval =800;
    Delay_ms(10);
    if(0 == flag)
   ｛
       Delay_ms(20);
       pwmval --;
    }
    else
   {
     pwmval +=20;
   }
   if(pwmval>879)
   {
     flag =  1;
   }
    if(pwmval<749)
    {
    flag = 0;
   }  
  TIM_SetCompare1(TIM1,pwmval);
  TIM_SetCompare2(TIM2,899-pwmval);
}



int main ( void)
{
   Peripheral_Configuration();
   PWM_Init();
   while(1)
  ｛
        PWM_Breath();
   ｝
   return 0;
}