关于STM32采集频率问题—求助求助

云边有个你 · 发表于 2021-12-5 16:44:52

关于STM32采集频率问题
如题所示，我使用stm32f103rct6，采用外部计数方式采集频率，重要代码如下：

#include "Fre.h"

void RCC_Configuration(void)
{
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
}

void GPIO_Configuration(void)
{
   GPIO_InitTypeDef GPIO_InitStructure;
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void Time_Configuration()
{
   TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
   TIM_TimeBaseStructure.TIM_Prescaler = 0;
   TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
   //TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
   TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
   TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);  // Time base configuration

   TIM_ITRxExternalClockConfig(TIM2,TIM_TS_ETRF);

   TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0);
//    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
   TIM_SetCounter(TIM2, 0);
   TIM_Cmd(TIM2, ENABLE);
}

//定时器定时函数定时250ms
void TIM5_Timer(void)
{
   TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
   NVIC_InitTypeDef NVIC_InitStructure;
   TIM_TimeBaseStructure.TIM_Period =2499;
   TIM_TimeBaseStructure.TIM_Prescaler = (7200-1);
   TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
   TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure); // Time base configuration
   TIM_ClearFlag(TIM5,TIM_FLAG_Update);
   TIM_ITConfig(TIM5,TIM_IT_Update,ENABLE );
   TIM_Cmd(TIM5, ENABLE);

   NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;
   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);
}

//中断服务函数
#if 1
void TIM5_IRQHandler(void)
{
u32 CAPTURE1;
int count;
u32 sum;
volatile  u32 Frequency1;
if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)
      {
         TIM_ClearITPendingBit(TIM5, TIM_IT_Update);
CAPTURE1=(u32)TIM_GetCounter(TIM2);

         //CAPTURE2=(u32)TIM_GetCounter(TIM1);
}
sum+=CAPTURE1;
count++;
if(count==4)
      {
Frequency1=(sum/4/0.25);
sum=0;
count=0;
      }
TIM_SetCounter(TIM2,0);
}
#endif

主函数部分如下：
int main(void)
{
int i;

u32 Frequency1;
      SystemInit();

RCC_Configuration();
GPIO_Configuration();
Time_Configuration();
TIM5_Timer();
// TIM5_IRQHandler();

   uart_init(115200);

while(1)
         {
               printf("Frequency1 is %d HZ.\r\n",Frequency1);
            //  printf("Frequency2 is %d HZ.\r\n",Frequency2);
            //Delayms(10);
         for(i=0;i<1000000;i++)
            {}
      }

}

但是测得信号频率显示如下：

自己找不出出错的原因，求各位大佬赐教，自己急需频率计