STM32PWM输入捕获模式源码

void TIM5_Configuration(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_ICInitTypeDef TIM_ICInitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE); //时钟配置

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;

//GPIO配置

GPIO_InitStructure.GPIO_Mode =

GPIO_Mode_IN_FLOATING;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_TimeBaseStructure.TIM_Period = 60000; //周期0～FFFF

TIM_TimeBaseStructure.TIM_Prescaler = 22; //时钟分频，分频数为5+1即6分频

TIM_TimeBaseStructure.TIM_ClockDivision = 0; //时钟分割TIM_TimeBaseStructure.TIM_CounterMode =

TIM_CounterMode_Up;//模式

TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);//基本初始化

NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;

//NVIC配置

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;

//通道选择

TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿触发

TIM_ICInitStructure.TIM_ICSelection =

TIM_ICSelection_DirectTI; //管脚与寄存器对应关系TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //输入预分频。意思是控制在多少个输入周期做一次捕获，如果//输入的信号频率没有变，测得的周期也不会变。比如选择4分频，则每四个输入周期才做一次捕获，这样在输入信号变化不频繁的情况下，

//可以减少软件被不断中断的次数。

TIM_ICInitStructure.TIM_ICFilter = 0x0;

//滤波设置，经历几个周期跳变认定波形稳定0x0～0xF

TIM_PWMIConfig(TIM5, &TIM_ICInitStructure);

//根据参数配置TIM外设信息

TIM_SelectInputTrigger(TIM5, TIM_TS_TI2FP2);

//选择IC2为始终触发源

TIM_SelectSlaveMode(TIM5, TIM_SlaveMode_Reset);//TIM从模式：触发信号的上升沿重新初始化计数器和触发寄存器的更新事件

TIM_SelectMasterSlaveMode(TIM5,

TIM_MasterSlaveMode_Enable); //启动定时器的被动触发

TIM_Cmd(TIM5, ENABLE);

//启动TIM2

TIM_ITConfig(TIM5, TIM_IT_CC2, ENABLE); //打开中断

}

//中断处理函数

void TIM5_IRQHandler(void)

{

TIM_ClearITPendingBit(TIM5, TIM_IT_CC2);

//清楚TIM的中断待处理位

IC2Value = TIM_GetCapture2(TIM5);

//读取IC2捕获寄存器的值，即为PWM周期的计数值

if (IC2Value != 0)

{

DutyCycle = (TIM_GetCapture1(TIM5) * 100) / IC2Value; //读取IC1捕获寄存器的值，并计算占空比

// led0pwmval3=led0pwmval4=DutyCycle;

// Frequency = 72000000 / IC2Value;

//计算PWM频率。

}

else

{

DutyCycle = 0;

//Frequency = 0; }

}