STM32 时钟 、中断、定时器使用

  

函数RCC_APB1PeriphClockCmd() 和RCC_APB2PeriphClockCmd(),RCC_AHBPeriphClockCmd()

第一个参数形式如下RCC_APB2Periph_GPIOA 或者RCC_APB1Periph_TIM3

 

/** @defgroup APB2_peripheral
AFIO GPIOA GPIOB GPIOC ....GPIOG ADC1 ADC2 ADC3 SPI1 UART1 TIM1 TIM8 TIM9~11 TIM15~17

注意：AFIO当事件控制、重映射、外部中断需要使能AFIO时钟。

/** @defgroup APB1_peripheral
TIM2~7 TIM12~14 WWDG USB CAN1 CAN2 PWR DAC SPI2 SPI3 UART2~5 I2C1 I2C2

 

中断优先级分组

一般使用NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);设置一次。

 以PE2为例，使用外部中断。

//初始化代码
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOE,ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_2;//KEY2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉输入
GPIO_Init(GPIOE, &GPIO_InitStructure);//

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);    //使能复用时钟
GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource2);

EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

EXTI_InitStructure.EXTI_Line=EXTI_Line2;    //KEY2
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;    
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;//下降沿触发
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);


NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn;//使能外部中断2通道            
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;                    
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                                
NVIC_Init(&NVIC_InitStructure);

//中断相应函数
void EXTI2_IRQHandler(void)
{
    delay_ms(10);//消抖
    if(KEY2==0)      //按键PE2
    {
        LED0=!LED0;
    }         
    EXTI_ClearITPendingBit(EXTI_Line2);  //清除line2上的中断标志位
}

 

定时器

 使用内部时钟

 

 以TIM3为例子，使用定时器中断。

//arr自动装载值
//psc时钟预分频数
void TIM3_Int_Init(u16 arr,u16 psc)
{
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //使能时钟
    TIM_TimeBaseStructure.TIM_Period = arr; 
    TIM_TimeBaseStructure.TIM_Prescaler =psc; 
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //时钟分割TDTS = Tck_tim
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //向上计数
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //
    TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //允许更新中断
    //中断优先级设置
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //TIM3
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 
    NVIC_Init(&NVIC_InitStructure);  
    TIM_Cmd(TIM3, ENABLE);  //使能TIM3                 
}
//中断服务程序
void TIM3_IRQHandler(void)   //TIM3ÖжÏ
{
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)  //检查Tim3中断发生与否
        {
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update  );  //清除标志
        LED1=!LED1;
        }
}

 在主函数中，比如500ms中断一次

TIM3_Int_Init(4999,7199);//10Kh计数频率，计数5000为500ms