刚刚接触F4为啥我使用TIMETR 外部计数测频率一点都不准呢。。测量部分代码如下

dididede · 发表于 2020-5-29 17:52:55

#include "cap.h"
#include "delay.h"
#include "goal.h"
#include "stdio.h"

void time2_init(void)
{

   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
   TIM_TimeBaseInitTypeDef  TimeBaseStructure;
   NVIC_InitTypeDef NVIC_InitStructure;
   TIM_DeInit(TIM2);
TimeBaseStructure.TIM_Period=9999;
   TimeBaseStructure.TIM_Prescaler=8399;
   TimeBaseStructure. TIM_CounterMode=TIM_CounterMode_Up;
   TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
   TIM_TimeBaseInit(TIM2,&TimeBaseStructure);

TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);

// TIM_Cmd(TIM2,ENABLE);

  NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_Init(&NVIC_InitStructure);
TIM_Cmd(TIM2,ENABLE);
}

void time_cap_init(void)
{
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD,ENABLE);
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);

   TIM_TimeBaseInitTypeDef  TimeBaseStructure;
   GPIO_InitTypeDef  GPIO_InitStructure;

   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

GPIO_Init(GPIOD,&GPIO_InitStructure);

   GPIO_PinAFConfig(GPIOD,GPIO_PinSource2,GPIO_AF_TIM3);

   TimeBaseStructure.TIM_Period=0XFFFFFFFF;
   TimeBaseStructure.TIM_Prescaler=0X0;
   TimeBaseStructure. TIM_CounterMode=TIM_CounterMode_Up;
   TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

   TIM_TimeBaseInit(TIM3,&TimeBaseStructure);
   TIM_ETRClockMode2Config(TIM3, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0);

TIM_SetCounter(TIM3,0);
TIM_Cmd(TIM3,ENABLE);
}

void TIM2_IRQHandler(void)
{
      if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
      {
   TIM_ClearITPendingBit (TIM2,TIM_IT_Update);
            fre_input= TIM_GetCounter(TIM3);
            TIM_SetCounter(TIM3,0);

      }
}