20200805-PWM呼吸灯-stm32-刘凯

主函数

TIM3_Configuration

void TIM3_Configuration(void)
{
    GPIO_InitTypeDef	GPIO;		//声明一个结构体变量
    TIM_TimeBaseInitTypeDef	TIM_TimeBaseStructure;
    TIM_OCInitTypeDef	TIM_OCInitStructure;
    /*-----------RCC  -------------*/
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);//开启定时器时钟
    /*-----------GPIO -------------*/
    //pwm---led灯  PB5
    GPIO.GPIO_Pin = GPIO_Pin_5; 	//选择PX.5
    GPIO.GPIO_Speed = GPIO_Speed_50MHz;	 //管脚频率为50MHZ
    GPIO.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOB,&GPIO);				 //初始化GPIOB寄存器
    GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE);//重映射
    /*-----------Configures TIM3 -------------*/
    TIM_DeInit(TIM3);
    TIM_TimeBaseStructure.TIM_Prescaler = 0 ; 	//72M
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up ;  	//计数向上
    TIM_TimeBaseStructure.TIM_Period = 0xff;						   //分频值
    TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;						//分割
    TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);

    /* Configures the TIM3 Channel2 in PWM Mode */
    TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Channel = TIM_Channel_2;
    TIM_OCInitStructure.TIM_Pulse = 0x0F;//低电平时间-----------亮灯时间
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;//TIM_OCPolarity_High
    TIM_OC2Init(TIM3, &TIM_OCInitStructure);//开通道2
    //.void TIM_OC2Init()?void TIM_OCInit()?????????????-OpenEdv-?????
    //http://www.openedv.com/posts/list/16055.htm
    //TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);			//使能预装载
    TIM_Cmd(TIM3,ENABLE);
}

TIM2_Configuration

void TIM2_Configuration(u16 ms)
{
    /*-----------定义结构体变量----------------*/
    TIM_TimeBaseInitTypeDef	 TIM_TimeBaseStructure;
    TIM_OCInitTypeDef	     TIM_OCInitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
	
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);//开启定时器时钟

    /*-----------中断优先级----------------*/
	
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);	//选择向量优先级组
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel; //选择中断向量通道为定时器2的通道
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先优先级为0
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;	//亚优先级为0
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;	   //使能中断向量
    NVIC_Init(&NVIC_InitStructure);	//完成初始化
    /*-----------Configures TIM2 -------------*/
    TIM_DeInit(TIM2);
    TIM_InternalClockConfig(TIM2);

    TIM_TimeBaseStructure.TIM_Period = 2*ms;   		  //下个更新事件发生时自动装载的周期值
    TIM_TimeBaseStructure.TIM_Prescaler = 36000;	  //时钟的分频值为35999，则时钟分频36000
    TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;	  //设置时钟分割
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;	//向上计数
    TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;	//输出比较时间模式
//	TIM_OCInitStructure.TIM_Pulse = 0x0; //脉冲值  设置待转入捕获寄存器的脉冲值（定时器模式配置为输出比较模式）
    TIM_OC1Init(TIM2,&TIM_OCInitStructure);

    TIM_Cmd(TIM2,ENABLE);//使能TIM2

    TIM_PrescalerConfig(TIM2,36000,TIM_PSCReloadMode_Immediate);//让定时器预分频值立即装入

    TIM_ClearFlag(TIM2,TIM_FLAG_Update); //清除中断标志

    TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE); //使能定时器中断
}

it.c文件

extern u16 timer;

	void TIM2_IRQHandler(void)
{
	static u8 f=0;
//	timer++;
//	if(timer>=255)timer=0;
		if(f==0)
		{
			timer++;if(timer>=0xff){f=1;timer=0xff;}
		}
		else
		{
			timer--;if(timer<=0){f=0;timer=0;}
		}
	TIM_SetCompare2(TIM3, timer);
	
	TIM_ClearITPendingBit(TIM2, TIM_IT_Update);	 // 清除TIM2的中断源 ;
}