通过debug查看相应的寄存器已经改变，但是示波器看波形是满占空比，下面是初始化代码
void TIM14_PWM_Init(unsigned int arr,unsigned int psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14,ENABLE); //TIM14时钟使能
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //使能PORTA时钟
GPIO_PinAFConfig(GPIOA,GPIO_PinSource7,GPIO_AF_TIM14); //GPIOA7复用为定时器14
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //GPIOA7
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA7
TIM_TimeBaseStructure.TIM_Prescaler=psc; //定时器分频
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseStructure.TIM_Period=arr; //自动重装载值
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_TimeBaseInit(TIM14,&TIM_TimeBaseStructure);//初始化定时器14
//初始化TIM14 Channel1 PWM模式
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性:TIM输出比较极性低
TIM_OC1Init(TIM14, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM1 4OC1
TIM_OC1PreloadConfig(TIM14, TIM_OCPreload_Enable); //使能TIM14在CCR1上的预装载寄存器
TIM_ARRPreloadConfig(TIM14,ENABLE);//ARPE使能
TIM_Cmd(TIM14, ENABLE); //使能TIM14 |
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