stm32测量频率电路

可以使用STM32的定时器模块来测量频率，具体步骤如下：

1. 将要测量的信号输入到STM32的GPIO口上。

2. 配置STM32的定时器模块为输入捕获模式，并设置捕获信号的输入端口。

3. 开始定时器计数，并在输入捕获事件发生时，读取捕获寄存器的值，得到捕获信号的脉宽。

4. 根据脉宽计算出频率。

下面是一个简单的示例代码：

#include "stm32f10x.h"

#define TIMx                    TIM2
#define TIMx_CLK                RCC_APB1Periph_TIM2
#define TIMx_IRQn               TIM2_IRQn
#define TIMx_IRQHandler         TIM2_IRQHandler

#define GPIO_PIN_INPUT          GPIO_Pin_0
#define GPIO_PORT_INPUT         GPIOA
#define GPIOx_CLK_INPUT         RCC_APB2Periph_GPIOA
#define GPIOx_SOURCE_INPUT      GPIO_PinSource0

volatile uint32_t g_capture = 0;
volatile uint32_t g_frequency = 0;

void TIMx_IRQHandler(void)
{
    if (TIM_GetITStatus(TIMx, TIM_IT_CC1) != RESET)
    {
        TIM_ClearITPendingBit(TIMx, TIM_IT_CC1);
        g_capture = TIM_GetCapture1(TIMx);
        TIM_SetCounter(TIMx, 0);
    }
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(GPIOx_CLK_INPUT, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_PIN_INPUT;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
    GPIO_Init(GPIO_PORT_INPUT, &GPIO_InitStructure);

    GPIO_PinRemapConfig(GPIO_Remap_TIM2, ENABLE);
}

void TIM_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_ICInitTypeDef TIM_ICInitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(TIMx_CLK, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIMx, &TIM_TimeBaseStructure);

    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICFilter = 0x0;
    TIM_ICInit(TIMx, &TIM_ICInitStructure);

    TIM_ITConfig(TIMx, TIM_IT_CC1, ENABLE);

    NVIC_InitStructure.NVIC_IRQChannel = TIMx_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_Cmd(TIMx, ENABLE);
}

int main(void)
{
    GPIO_Configuration();
    TIM_Configuration();

    while (1)
    {
        g_frequency = 1000000 / g_capture; // 假设输入的是1MHz方波
    }
}

在上述代码中，我们使用了TIM2的通道1来捕获输入信号，并在捕获事件发生时，读取捕获寄存器的值。根据假设输入的是1MHz方波的条件，我们可以通过捕获寄存器的值计算出频率。