stm32+pwm+呼吸灯

以下是基于STM32的PWM呼吸灯实现方法：

1. 首先需要在STM32上配置TIM1的CH1通道为PWM输出模式，并设置PWM的周期和占空比。

2. 然后需要通过按键中断来控制PWM占空比的增加和减少。具体实现方法如下：

   // 定义按键的GPIO引脚和中断优先级
   #define KEY0_GPIO_PIN GPIO_PIN_0
   #define KEY0_GPIO_PORT GPIOA
   #define KEY0_EXTI_IRQn EXTI0_IRQn
   #define KEY0_IRQ_PRIORITY 2
   
   #define KEY1_GPIO_PIN GPIO_PIN_13
   #define KEY1_GPIO_PORT GPIOC
   #define KEY1_EXTI_IRQn EXTI15_10_IRQn
   #define KEY1_IRQ_PRIORITY 2
   
   // 定义PWM的周期和占空比
   #define PWM_PERIOD 1000
   #define PWM_MIN_DUTY_CYCLE 0
   #define PWM_MAX_DUTY_CYCLE 900
   
   // 定义PWM的当前占空比
   uint16_t pwm_duty_cycle = 0;
   
   // 定义按键的状态和计数器
   uint8_t key0_state = 0;
   uint8_t key1_state = 0;
   uint16_t key0_counter = 0;
   uint16_t key1_counter = 0;
   
   // 定义PWM输出的GPIO引脚
   #define PWM_GPIO_PIN GPIO_PIN_8
   #define PWM_GPIO_PORT GPIOA
   
   // 初始化PWM输出的GPIO引脚
   HAL_GPIO_Init(PWM_GPIO_PORT, &(GPIO_InitTypeDef){
       .Pin = PWM_GPIO_PIN,
       .Mode = GPIO_MODE_AF_PP,
       .Pull = GPIO_NOPULL,
       .Speed = GPIO_SPEED_FREQ_HIGH,
       .Alternate = GPIO_AF1_TIM1
   });
   
   // 初始化TIM1的CH1通道为PWM输出模式
   HAL_TIM_PWM_Init(&(TIM_HandleTypeDef){
       .Instance = TIM1
   });
   HAL_TIM_PWM_ConfigChannel(&(TIM_HandleTypeDef){
       .Instance = TIM1
   }, &(TIM_OC_InitTypeDef){
       .OCMode = TIM_OCMODE_PWM1,
       .Pulse = pwm_duty_cycle,
       .OCPolarity = TIM_OCPOLARITY_HIGH
   }, TIM_CHANNEL_1);
   
   // 初始化按键的GPIO引脚和中断
   HAL_GPIO_Init(KEY0_GPIO_PORT, &(GPIO_InitTypeDef){
       .Pin = KEY0_GPIO_PIN,
       .Mode = GPIO_MODE_IT_FALLING,
       .Pull = GPIO_PULLUP,
       .Speed = GPIO_SPEED_FREQ_HIGH
   });
   HAL_NVIC_SetPriority(KEY0_EXTI_IRQn, KEY0_IRQ_PRIORITY, 0);
   HAL_NVIC_EnableIRQ(KEY0_EXTI_IRQn);
   
   HAL_GPIO_Init(KEY1_GPIO_PORT, &(GPIO_InitTypeDef){
       .Pin = KEY1_GPIO_PIN,
       .Mode = GPIO_MODE_IT_FALLING,
       .Pull = GPIO_PULLUP,
       .Speed = GPIO_SPEED_FREQ_HIGH
   });
   HAL_NVIC_SetPriority(KEY1_EXTI_IRQn, KEY1_IRQ_PRIORITY, 0);
   HAL_NVIC_EnableIRQ(KEY1_EXTI_IRQn);
   
   // 在while循环中不断更新PWM占空比
   while (1) {
       // 更新PWM占空比
       __HAL_TIM_SET_COMPARE(&(TIM_HandleTypeDef){
           .Instance = TIM1
       }, TIM_CHANNEL_1, pwm_duty_cycle);
   
       // 控制LED2的闪烁
       HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_0);
       HAL_Delay(500);
   }
   
   // KEY0的中断处理函数
   void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
       if (GPIO_Pin == KEY0_GPIO_PIN) {
           // 检测按键状态
           if (HAL_GPIO_ReadPin(KEY0_GPIO_PORT, KEY0_GPIO_PIN) == GPIO_PIN_RESET) {
               key0_counter++;
               if (key0_counter >= 1000) {
                   key0_state = 1;
                   key0_counter = 0;
               }
           } else {
               key0_counter = 0;
               if (key0_state == 1) {
                   // 增加PWM占空比
                   pwm_duty_cycle += 100;
                   if (pwm_duty_cycle > PWM_MAX_DUTY_CYCLE) {
                       pwm_duty_cycle = PWM_MAX_DUTY_CYCLE;
                   }
                   key0_state = 0;
               }
           }
       }
   }
   
   // KEY1的中断处理函数
   void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
       if (GPIO_Pin == KEY1_GPIO_PIN) {
           // 检测按键状态
           if (HAL_GPIO_ReadPin(KEY1_GPIO_PORT, KEY1_GPIO_PIN) == GPIO_PIN_RESET) {
               key1_counter++;
               if (key1_counter >= 1000) {
                   key1_state = 1;
                   key1_counter = 0;
               }
           } else {
               key1_counter = 0;
               if (key1_state == 1) {
                   // 减少PWM占空比
                   pwm_duty_cycle -= 100;
                   if (pwm_duty_cycle < PWM_MIN_DUTY_CYCLE) {
                       pwm_duty_cycle = PWM_MIN_DUTY_CYCLE;
                   }
                   key1_state = 0;
               }
           }
       }
   }

3. 最后需要控制LED1的亮度呼吸灯效果。具体实现方法如下：

   // 在while循环中不断更新PWM占空比
   while (1) {
       // 更新PWM占空比
       __HAL_TIM_SET_COMPARE(&(TIM_HandleTypeDef){
           .Instance = TIM1
       }, TIM_CHANNEL_1, pwm_duty_cycle);
   
       // 控制LED1的呼吸灯效果
       for (int i = 0; i < 100; i++) {
           __HAL_TIM_SET_COMPARE(&(TIM_HandleTypeDef){
               .Instance = TIM1
           }, TIM_CHANNEL_1, i * 9);
           HAL_Delay(10);
       }
       for (int i = 100; i >= 0; i--) {
           __HAL_TIM_SET_COMPARE(&(TIM_HandleTypeDef){
               .Instance = TIM1
           }, TIM_CHANNEL_1, i * 9);
           HAL_Delay(10);
       }
   }