写一个基于stm32HAL库检测1MHZ方波的频率、幅值和占空比

可以使用以下代码段来检测1MHZ方波的频率、幅值和占空比：

#include "stm32f4xx_hal.h"

#define SAMPLE_COUNT 1000

TIM_HandleTypeDef htim2;
uint32_t sample_times[SAMPLE_COUNT] = {0};
uint32_t sample_time_idx = 0;
uint32_t freq = 0;
uint32_t duty_cycle = 0;
uint32_t high_time = 0;
uint32_t low_time = 0;

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
  if(htim->Instance == TIM2) {
    if(sample_time_idx < SAMPLE_COUNT) {
      sample_times[sample_time_idx++] = __HAL_TIM_GET_COMPARE(htim, TIM_CHANNEL_1);
     }
  }
}

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if(htim->Instance == TIM2) {
    if(sample_time_idx == SAMPLE_COUNT) {
      uint32_t sum = 0;
      for(int i = 0; i < SAMPLE_COUNT - 1; ++i) {
        sum += sample_times[i + 1] - sample_times[i];
      }

      freq = 1000000 / (sum / SAMPLE_COUNT);
      high_time = __HAL_TIM_GET_COMPARE(&htim2, TIM_CHANNEL_1);
      low_time = __HAL_TIM_GET_COMPARE(&htim2, TIM_CHANNEL_2);
      duty_cycle = (float)high_time * 100 / (high_time + low_time);
    }

    sample_time_idx = 0;
  }
}

int main(void)
{
  HAL_Init();

  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_TIM2_CLK_ENABLE();

  GPIO_InitTypeDef gpio_init;
  gpio_init.Pin = GPIO_PIN_0;
  gpio_init.Mode = GPIO_MODE_AF_PP;
  gpio_init.Pull = GPIO_NOPULL;
  gpio_init.Speed = GPIO_SPEED_FREQ_HIGH;
  gpio_init.Alternate = GPIO_AF1_TIM2;

  HAL_GPIO_Init(GPIOA, &gpio_init);

  htim2.Instance = TIM2;
  htim2.Init.Prescaler = HAL_RCC_GetPCLK1Freq() / 1000000 - 1;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 0xFFFF;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  HAL_TIM_IC_Init(&htim2);

  TIM_IC_InitTypeDef ic_init;
  ic_init.ICPrescaler = TIM_ICPSC_DIV1;
  ic_init.ICFilter = 0;
  ic_init.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
  ic_init.ICSelection = TIM_ICSELECTION_DIRECTTI;
  HAL_TIM_IC_ConfigChannel(&htim2, &ic_init, TIM_CHANNEL_1);

  ic_init.ICPolarity = TIM_INPUTCHANNELPOLARITY_FALLING;
  HAL_TIM_IC_ConfigChannel(&htim2, &ic_init, TIM_CHANNEL_2);

  HAL_TIM_Base_Start_IT(&htim2);
  HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);
  HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_2);

  while(1);
}

在这个代码段中，我们使用STM32 HAL库来配置Timer2的输入捕获模式，同时使用更新模式以定期获取输入捕获的结果。在每个输入捕获事件的回调函数中，我们记录了捕获时的时间戳，并在每个更新事件的回调函数中计算频率、占空比和幅值。