基于stm32定时器做秒表

1. 硬件准备

（1）STM32芯片，推荐使用STM32F103系列。

（2）LED灯，用于显示秒表计时结果。

（3）按键，用于启动、停止和复位秒表。

2. 软件设计

（1）初始化定时器

使用STM32的定时器功能，可以快速地实现秒表计时。在初始化时，需要设置定时器的时钟源、分频系数、计数模式、自动重载值等参数。

（2）计时

在定时器中断服务函数中，每次中断后将计数值加1，然后将计数值转换成秒表显示格式，并输出到LED灯上。

（3）按键控制

使用GPIO中断，当按键按下时触发中断，然后根据按键的不同操作，控制秒表的启动、停止和复位。

3. 代码实现

以下是基于STM32F103的秒表代码实现，其中TIM2为定时器2，PA0、PA1、PA2分别为控制秒表的启动、停止和复位的按键，PB12为LED灯控制引脚。

#include "stm32f10x.h"

uint16_t count = 0;
uint8_t sec, min, hour;

void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
    {
        count++;
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}

void EXTI0_IRQHandler(void)
{
    if (EXTI_GetITStatus(EXTI_Line0) != RESET)
    {
        TIM_Cmd(TIM2, ENABLE);
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

void EXTI1_IRQHandler(void)
{
    if (EXTI_GetITStatus(EXTI_Line1) != RESET)
    {
        TIM_Cmd(TIM2, DISABLE);
        EXTI_ClearITPendingBit(EXTI_Line1);
    }
}

void EXTI2_IRQHandler(void)
{
    if (EXTI_GetITStatus(EXTI_Line2) != RESET)
    {
        TIM_Cmd(TIM2, DISABLE);
        count = 0;
        EXTI_ClearITPendingBit(EXTI_Line2);
    }
}

void TIM2_Config(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
    NVIC_InitTypeDef NVIC_InitStruct;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseInitStruct.TIM_Prescaler = 7199;
    TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStruct.TIM_Period = 999;
    TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);

    TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

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

    TIM_Cmd(TIM2, DISABLE);
}

void GPIO_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    EXTI_InitTypeDef EXTI_InitStruct;
    NVIC_InitTypeDef NVIC_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    EXTI_InitStruct.EXTI_Line = EXTI_Line0 | EXTI_Line1 | EXTI_Line2;
    EXTI_InitStruct.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStruct.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStruct.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStruct);

    NVIC_InitStruct.NVIC_IRQChannel = EXTI0_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    NVIC_InitStruct.NVIC_IRQChannel = EXTI1_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    NVIC_InitStruct.NVIC_IRQChannel = EXTI2_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 2;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStruct);
}

void LED_Display(void)
{
    sec = count % 60;
    min = count / 60 % 60;
    hour = count / 3600 % 24;

    GPIO_WriteBit(GPIOB, GPIO_Pin_12, (BitAction)(count % 2));
}

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

    while (1)
    {
        LED_Display();
    }
}