stm32 按键长按短按组合按键状态机

实现按键的长按、短按和组合按键功能可以通过状态机来实现。下面提供一个简单的示例代码，以两个按键为例，一个为K1，一个为K2。

首先定义状态：

typedef enum {
  KEY_IDLE_STATE,
  KEY_SHORT_PRESS_STATE,
  KEY_LONG_PRESS_STATE,
  KEY_COMB_PRESS_STATE
} KEY_STATE;

然后定义按键结构体：

typedef struct {
  GPIO_TypeDef *port;
  uint16_t pin;
  uint32_t long_press_time;
  uint32_t comb_press_time;
  uint32_t last_time;
  uint8_t comb_flag;
  KEY_STATE state;
} KEY_TypeDef;

其中，`port`和`pin`表示按键所在的GPIO口和引脚，`long_press_time`表示长按的时间阈值，`comb_press_time`表示组合按键的时间阈值，`last_time`表示上次检测按键的时间，`comb_flag`表示组合按键标志，`state`表示当前状态。

接下来定义状态转换函数：

static void key_state_transfer(KEY_TypeDef *key)
{
  uint32_t current_time = HAL_GetTick();
  switch (key->state) {
    case KEY_IDLE_STATE:
      if (HAL_GPIO_ReadPin(key->port, key->pin) == GPIO_PIN_RESET) {
        key->state = KEY_SHORT_PRESS_STATE;
        key->last_time = current_time;
      }
      break;
    case KEY_SHORT_PRESS_STATE:
      if (HAL_GPIO_ReadPin(key->port, key->pin) == GPIO_PIN_SET) {
        key->state = KEY_IDLE_STATE;
        if (current_time - key->last_time < key->long_press_time) {
          // 短按
        } else {
          // 长按
        }
      } else {
        if (current_time - key->last_time >= key->comb_press_time) {
          key->state = KEY_COMB_PRESS_STATE;
          key->comb_flag = 1;
        }
      }
      break;
    case KEY_LONG_PRESS_STATE:
      if (HAL_GPIO_ReadPin(key->port, key->pin) == GPIO_PIN_SET) {
        key->state = KEY_IDLE_STATE;
      }
      break;
    case KEY_COMB_PRESS_STATE:
      if (HAL_GPIO_ReadPin(key->port, key->pin) == GPIO_PIN_SET) {
        key->state = KEY_IDLE_STATE;
        if (key->comb_flag) {
          // 组合按键
        }
        key->comb_flag = 0;
      }
      break;
    default:
      key->state = KEY_IDLE_STATE;
      break;
  }
}

在主函数中循环调用按键状态转换函数即可：

KEY_TypeDef key1 = { GPIOA, GPIO_PIN_0, 1000, 500, 0, 0, KEY_IDLE_STATE };
KEY_TypeDef key2 = { GPIOA, GPIO_PIN_1, 1000, 500, 0, 0, KEY_IDLE_STATE };

while (1) {
  key_state_transfer(&key1);
  key_state_transfer(&key2);
}

上述代码实现了两个按键的长按、短按和组合按键功能，你可以根据实际需要进行修改和扩展。