关于TIM1的外部计数模式测频率的问题，TIM3的ert管脚能正常使用，而TIM1的PA12接入就无法计数，貌似是GPIO口的问题，请大佬指导

葫芦wawa · 发表于 2019-8-10 16:55:28

#include "timer.h"
#include "led.h"
#include "usart.h"

void TIM1_Cap_Init(u16 arr,u16 psc)
{
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
GPIO_InitTypeDef GPIO_InitStructure;

/* TIM1 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

TIM_TimeBaseStructure.TIM_Prescaler = 0x00;
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);  // Time base configuration
TIM_ETRClockMode2Config(TIM1, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0);
TIM_SetCounter(TIM1, 0);
TIM_Cmd(TIM1, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

}
//TIM2作为计数器
void TIM2_Int_Init(u16 arr,u16 psc)
{
TIM_TimeBaseInitTypeDef TIM2_TimeBaseStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
/* TIM2 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  TIM_DeInit(TIM2);
  TIM2_TimeBaseStructure.TIM_Period =2499;
  TIM2_TimeBaseStructure.TIM_Prescaler = 7199;
  TIM2_TimeBaseStructure.TIM_ClockDivision = 0x0;
  TIM2_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM2, &TIM2_TimeBaseStructure); // Time base configuration
  TIM_ClearFlag(TIM2,TIM_FLAG_Update);
  TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE );

  TIM_Cmd(TIM2, ENABLE);
  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
u16 count;
int sum;
float Frequency1;
u32 CAPTURE1;
void TIM2_IRQHandler(void)
{
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) //判断定时器2是否发生更新（溢出）中断
      {
         TIM_ClearITPendingBit(TIM2, TIM_IT_Update);  //清除中断标志位

            CAPTURE1=(u32)TIM_GetCounter(TIM1); //获取计数器的值
      }
                     sum+=CAPTURE1;
                     count++;
                     if(count==4)
                     {
                        Frequency1=sum/4/0.25;
                        sum=0;
                        count=0;
                  printf("频率是： %f",Frequency1);
                  printf ("\r\n");
                     }
                     TIM_SetCounter(TIM1,0);
               LED2=!LED2;

}