STM32F407倒计时秒表设计的程序

以下是一个简单的倒计时和秒表程序的代码示例，仅供参考：

#include "stm32f4xx.h"

#define LED_GPIO_PORT GPIOA
#define LED_GPIO_PIN GPIO_Pin_5

void Delay(__IO uint32_t nCount);

void LED_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = LED_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(LED_GPIO_PORT, &GPIO_InitStructure);
}

void TIM2_Config(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 999; //1ms
    TIM_TimeBaseStructure.TIM_Prescaler = 8399; //84MHz/8400=10kHz
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM2, ENABLE);
}

void TIM2_IRQHandler(void)
{
    static uint16_t ms_count = 0;
    static uint16_t s_count = 0;
    static uint16_t min_count = 0;
    static uint16_t sec_count = 60;
    static uint8_t mode = 0; //0:倒计时 1:秒表

    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
    {
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
        ms_count++;

        if (ms_count >= 10)
        {
            ms_count = 0;

            if (mode == 0)
            {
                if (sec_count == 0)
                {
                    if (min_count == 0)
                    {
                        GPIO_SetBits(LED_GPIO_PORT, LED_GPIO_PIN);
                    }
                    else
                    {
                        min_count--;
                        sec_count = 59;
                    }
                }
                else
                {
                    sec_count--;
                }
            }
            else
            {
                s_count++;
                if (s_count >= 60)
                {
                    s_count = 0;
                    min_count++;
                }
            }
        }
    }
}

int main(void)
{
    LED_Init();
    TIM2_Config();

    while (1)
    {
        if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0) == RESET)
        {
            Delay(50);
            if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0) == RESET)
            {
                GPIO_ResetBits(LED_GPIO_PORT, LED_GPIO_PIN);
                sec_count = 5;
                min_count = 0;
                mode = 0;
            }
        }

        if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_1) == RESET)
        {
            Delay(50);
            if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_1) == RESET)
            {
                mode = 1;
                s_count = 0;
                min_count = 0;
                sec_count = 0;
            }
        }
    }
}

void Delay(__IO uint32_t nCount)
{
    while (nCount--);
}

此代码示例使用TIM2作为计时器，1ms中断一次。在中断服务程序中，分别处理倒计时和秒表功能。在main函数中，使用GPIO口检测按键状态，来控制计时器的启动、停止和复位操作。注意，此代码仅为示例，实际使用时需要根据具体需求进行修改。