stm32f10x输入捕获测占空比

输入捕获是一种通过定时器来测量外部信号的技术。在STM32F10x中，输入捕获可以用于测量外部信号的占空比。以下是一些相关的代码：

1. 设置定时器为输入捕获模式：

TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
TIM_TimeBaseInitStruct.TIM_Prescaler = 0;
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_Period = 65535;
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseInitStruct);

TIM_ICInitTypeDef TIM_ICInitStruct;
TIM_ICInitStruct.TIM_Channel = TIM_Channel_1;
TIM_ICInitStruct.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStruct.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStruct.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStruct.TIM_ICFilter = 0x0;
TIM_ICInit(TIM3, &TIM_ICInitStruct);

2. 启动定时器：

TIM_Cmd(TIM3, ENABLE);

3. 在中断函数中读取捕获值并计算占空比：

void TIM3_IRQHandler(void)
{
    if(TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)
    {
        static uint16_t lastValue = 0;
        uint16_t currentValue = TIM_GetCapture1(TIM3);
        uint16_t period = currentValue - lastValue;
        lastValue = currentValue;
        uint16_t pulseWidth = TIM_GetCapture2(TIM3);
        uint16_t dutyCycle = (pulseWidth * 100) / period;
        TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);
    }
}

在上面的代码中，我们使用了TIM3定时器的通道1来捕获外部信号的边沿，然后在中断函数中计算占空比。lastValue变量用于存储上一次捕获的值，currentValue变量用于存储当前捕获的值，period变量用于计算信号的周期，pulseWidth变量用于计算信号的脉宽，dutyCycle变量用于存储占空比。