stm32f072定时器1通道1 PWM配置，端口无波形输出

PWM配置如下：
/*************************************************

Function:    TIM1_Init()

Description:    pwm2输出

*************************************************/
void TIM1_Init_PWM2(uint16_t arr,uint16_t psc)
{
   
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
   
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOE,ENABLE);  
   
      
//PE9
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOE, &GPIO_InitStructure);
   
    GPIO_PinAFConfig(GPIOE, GPIO_PinSource9, GPIO_AF_2);   //TIM1channel
   
   
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);    //定时器TIM1时钟使能
    //TIM_DeInit(TIM1);
   //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
     TIM_TimeBaseStructure.TIM_Period=arr;     
    //设置用来作为TIMx时钟频率出书的预分频值
     TIM_TimeBaseStructure.TIM_Prescaler =psc;              
    //设置时钟分割
     TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    //设置计数模式   
     TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
     
     TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
     //初始化参数
     TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);               

    //TIM1的channel  
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
    TIM_OCInitStructure.TIM_Pulse = 0x90;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
    TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);  

    //TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);  
    //TIM_ARRPreloadConfig(TIM1,ENABLE);
    TIM_Cmd(TIM1, ENABLE);  //使能TIM1
    TIM_CtrlPWMOutputs(TIM1, ENABLE);

}
PWM配置后，PE9输出无波形