stm32两位秒表程序设计

以下是基于STM32的两位秒表程序设计，其中使用了HAL库。

首先，需要定义两个计数器变量和两个标志位，用于标记是否启动计时器：

uint16_t counter1 = 0;
uint16_t counter2 = 0;

uint8_t start_flag1 = 0;
uint8_t start_flag2 = 0;

然后，在SysTick中断处理函数中，对计数器进行累加，并在达到1秒时将标志位设置为0，表示计时结束：

void SysTick_Handler(void)
{
    counter1++;
    counter2++;
    
    if (counter1 == 1000) {
        counter1 = 0;
        start_flag1 = 0;
    }
    
    if (counter2 == 1000) {
        counter2 = 0;
        start_flag2 = 0;
    }
}

接下来，可以使用按键中断来启动和停止计时器。当按下按键时，将标志位设置为1，表示开始计时；当再次按下按键时，将标志位设置为0，表示停止计时：

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
    if (GPIO_Pin == GPIO_PIN_0) {
        if (start_flag1 == 0) {
            start_flag1 = 1;
            counter1 = 0;
        } else {
            start_flag1 = 0;
        }
    }
    
    if (GPIO_Pin == GPIO_PIN_1) {
        if (start_flag2 == 0) {
            start_flag2 = 1;
            counter2 = 0;
        } else {
            start_flag2 = 0;
        }
    }
}

最后，在主函数中，可以定时输出计数器的值，以显示秒表计时结果：

while (1)
{
    if (start_flag1 == 1) {
        printf("Counter 1: %d\n", counter1);
    }
    
    if (start_flag2 == 1) {
        printf("Counter 2: %d\n", counter2);
    }
    
    HAL_Delay(10);
}

完整的代码如下所示：

#include "stm32f1xx_hal.h"
#include "stdio.h"

uint16_t counter1 = 0;
uint16_t counter2 = 0;

uint8_t start_flag1 = 0;
uint8_t start_flag2 = 0;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();

  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
  HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);

  while (1)
  {
      if (start_flag1 == 1) {
          printf("Counter 1: %d\n", counter1);
      }
      
      if (start_flag2 == 1) {
          printf("Counter 2: %d\n", counter2);
      }
      
      HAL_Delay(10);
  }
}

void SysTick_Handler(void)
{
    counter1++;
    counter2++;
    
    if (counter1 == 1000) {
        counter1 = 0;
        start_flag1 = 0;
    }
    
    if (counter2 == 1000) {
        counter2 = 0;
        start_flag2 = 0;
    }
}

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
    if (GPIO_Pin == GPIO_PIN_0) {
        if (start_flag1 == 0) {
            start_flag1 = 1;
            counter1 = 0;
        } else {
            start_flag1 = 0;
        }
    }
    
    if (GPIO_Pin == GPIO_PIN_1) {
        if (start_flag2 == 0) {
            start_flag2 = 1;
            counter2 = 0;
        } else {
            start_flag2 = 0;
        }
    }
}

static void MX_GPIO_Init(void)
{
  __HAL_RCC_GPIOA_CLK_ENABLE();

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING_FALLING;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  HAL_NVIC_SetPriority(EXTI0_IRQn, 2, 0);
  HAL_NVIC_EnableIRQ(EXTI0_IRQn);

  HAL_NVIC_SetPriority(EXTI1_IRQn, 2, 0);
  HAL_NVIC_EnableIRQ(EXTI1_IRQn);
}

void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}