#include "stm32f10x.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_tim.h"

// 呼吸灯亮度变化步进值
#define STEP_VALUE 5
// 呼吸灯周期时间（毫秒）
#define BREATH_PERIOD 2000

// PWM占空比变量
static uint16_t pwm_duty = 0;
// 亮度变化方向：1表示变亮，0表示变暗
static uint8_t bright_direction = 1;

// 初始化GPIO
void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    // 使能GPIOA时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    // 配置PA0为推挽输出
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

// 初始化定时器2用于PWM
void TIM2_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    // 使能TIM2时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    // 定时器基本配置
    TIM_TimeBaseStructure.TIM_Period = 999;        // PWM频率为72MHz/(999+1)=72kHz
    TIM_TimeBaseStructure.TIM_Prescaler = 0;      // 不分频
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;  // 时钟分频因子
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  // 向上计数
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    // 启动定时器
    TIM_Cmd(TIM2, ENABLE);
}

// 初始化定时器3用于呼吸灯控制
void TIM3_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    // 使能TIM3时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

    // 定时器基本配置，每2ms触发一次中断
    TIM_TimeBaseStructure.TIM_Period = 1999;      // 72MHz/2000=36kHz
    TIM_TimeBaseStructure.TIM_Prescaler = 2000;   // 分频2000
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    // 使能定时器更新中断
    TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);

    // 配置NVIC
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // 启动定时器
    TIM_Cmd(TIM3, ENABLE);
}

// 定时器3中断服务函数
void TIM3_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
    {
        // 清除中断标志
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);

        // 根据方向调整PWM占空比
        if (bright_direction)
        {
            pwm_duty += STEP_VALUE;
            if (pwm_duty >= 1000)
            {
                pwm_duty = 1000;
                bright_direction = 0;  // 开始变暗
            }
        }
        else
        {
            pwm_duty -= STEP_VALUE;
            if (pwm_duty <= 0)
            {
                pwm_duty = 0;
                bright_direction = 1;  // 开始变亮
            }
        }

        // 更新PWM输出
        GPIO_WriteBit(GPIOA, GPIO_Pin_0, (pwm_duty > 500) ? Bit_SET : Bit_RESET);
    }
}

int main(void)
{
    // 系统初始化
    SystemInit();

    // 初始化GPIO
    GPIO_Configuration();

    // 初始化定时器
    TIM2_Configuration();
    TIM3_Configuration();

    while (1)
    {
        // 主循环为空，所有工作在中断中完成
    }
}