stm32F429外部時鐘模式頻率測量極限

之前用F1進行測試發現極限性能是二十兆左右，最近用F429測試極限測量頻率為68M左右！
原理很簡單就是用一個定時器做閥門，每隔一段時間進入一次中斷開啟測量，另一個定時器配置為外部時鐘源模式2，每來一個脈沖就進行計數加一，這樣還不夠，要將每次溢出的次數也做記錄，才能將極限測量值提高，當然我水平有限，只能到這些了，有更好辦法的也可以分享下~

以下是定時器部分核心代碼：
/**
  ******************************************************************************
  * File Name          : TIM.c
  * Description        : This file provides code for the configuration
  *                      of the TIM instances.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "tim.h"

/* USER CODE BEGIN 0 */
uint16_t num=0;
uint8_t i=0;
uint32_t frequency=0;
uint32_t cnt=0;
/* USER CODE END 0 */

TIM_HandleTypeDef htim1;
TIM_HandleTypeDef htim8;

/* TIM1 init function */
void MX_TIM1_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 0;
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 0xFFFF;
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.RepetitionCounter = 0;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_ETRMODE2;
  sClockSourceConfig.ClockPolarity = TIM_CLOCKPOLARITY_NONINVERTED;
  sClockSourceConfig.ClockPrescaler = TIM_CLOCKPRESCALER_DIV1;
  sClockSourceConfig.ClockFilter = 0;
  if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }

}
/* TIM8 init function */
void MX_TIM8_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  htim8.Instance = TIM8;
  htim8.Init.Prescaler = 1799;
  htim8.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim8.Init.Period = 4999;
  htim8.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim8.Init.RepetitionCounter = 0;
  htim8.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim8) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim8, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim8, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }

}

void HAL_TIM_Base_MspInit(TIM_HandleTypeDef* tim_baseHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(tim_baseHandle->Instance==TIM1)
  {
  /* USER CODE BEGIN TIM1_MspInit 0 */

  /* USER CODE END TIM1_MspInit 0 */
    /* TIM1 clock enable */
    __HAL_RCC_TIM1_CLK_ENABLE();

    __HAL_RCC_GPIOE_CLK_ENABLE();
    /**TIM1 GPIO Configuration   
    PE7     ------> TIM1_ETR
    */
    GPIO_InitStruct.Pin = GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
    HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

    /* TIM1 interrupt Init */
    HAL_NVIC_SetPriority(TIM1_UP_TIM10_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM1_UP_TIM10_IRQn);
  /* USER CODE BEGIN TIM1_MspInit 1 */

  /* USER CODE END TIM1_MspInit 1 */
  }
  else if(tim_baseHandle->Instance==TIM8)
  {
  /* USER CODE BEGIN TIM8_MspInit 0 */

  /* USER CODE END TIM8_MspInit 0 */
    /* TIM8 clock enable */
    __HAL_RCC_TIM8_CLK_ENABLE();

    /* TIM8 interrupt Init */
    HAL_NVIC_SetPriority(TIM8_UP_TIM13_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM8_UP_TIM13_IRQn);
  /* USER CODE BEGIN TIM8_MspInit 1 */

  /* USER CODE END TIM8_MspInit 1 */
  }
}

void HAL_TIM_Base_MspDeInit(TIM_HandleTypeDef* tim_baseHandle)
{

  if(tim_baseHandle->Instance==TIM1)
  {
  /* USER CODE BEGIN TIM1_MspDeInit 0 */

  /* USER CODE END TIM1_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_TIM1_CLK_DISABLE();

    /**TIM1 GPIO Configuration   
    PE7     ------> TIM1_ETR
    */
    HAL_GPIO_DeInit(GPIOE, GPIO_PIN_7);

    /* TIM1 interrupt Deinit */
    HAL_NVIC_DisableIRQ(TIM1_UP_TIM10_IRQn);
  /* USER CODE BEGIN TIM1_MspDeInit 1 */

  /* USER CODE END TIM1_MspDeInit 1 */
  }
  else if(tim_baseHandle->Instance==TIM8)
  {
  /* USER CODE BEGIN TIM8_MspDeInit 0 */

  /* USER CODE END TIM8_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_TIM8_CLK_DISABLE();

    /* TIM8 interrupt Deinit */
    HAL_NVIC_DisableIRQ(TIM8_UP_TIM13_IRQn);
  /* USER CODE BEGIN TIM8_MspDeInit 1 */

  /* USER CODE END TIM8_MspDeInit 1 */
  }
}

/* USER CODE BEGIN 1 */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{

  if(htim->Instance==TIM1)
   {
       num++;
   }

   if(htim->Instance==TIM8)
   {   

       if(i<19)
       {
          cnt+=__HAL_TIM_GET_COUNTER(&htim1);
         __HAL_TIM_SET_COUNTER(&htim1,0);
         i++;
       }

       else
       {
         cnt+= __HAL_TIM_GET_COUNTER(&htim1);
         __HAL_TIM_SET_COUNTER(&htim1,0);



          frequency=cnt+num*65536;
           num=0;
         printf("定時器2:%ld\n",frequency);
          i=0;
          cnt=0;
       }  
   }


}
/* USER CODE END 1 */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

arduino下有人試過嗎？

我用stm32f103使用外部時鐘模式2一直不成功   能不能提供一下工程文件  麻煩你發到我的
找到了一個別人的例程是這樣的   但是不明白這一句是干嘛用的TIM_OCInitStructure.TIM_Pulse =10;修改的是CCR寄存器
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
        TIM_TimeBaseStructure.TIM_Prescaler =1-1;
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;                                                        
        TIM_TimeBaseStructure.TIM_Period = 109-1;
        TIM_TimeBaseStructure.TIM_ClockDivision = 0;
        TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
        TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
        
        TIM_SelectInputTrigger(TIM2,TIM_TS_ETRF);
        TIM_ETRClockMode2Config(TIM2,TIM_ExtTRGPSC_OFF,TIM_ExtTRGPolarity_NonInverted,0x02);//外部時鐘引腳,模式2
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;
        TIM_OCInitStructure.TIM_Pulse =10;
        TIM_OC1Init(TIM2,&TIM_OCInitStructure);
        TIM_ITConfig(TIM2,TIM_IT_CC1|TIM_IT_Update,ENABLE);
        TIM_ClearFlag(TIM2,TIM_FLAG_Update);
        TIM_ARRPreloadConfig(TIM2,ENABLE);
        TIM2->CNT = 0;
        TIM_Cmd(TIM2,DISABLE);//初始化之后是關閉的
//                TIM_Cmd(TIM2, ENABLE);