请问为什么用互斥量的现象是按一下按键，他还是会有抖动，灯还是会闪两次呢？

发布于 2022-10-01 10:59:52 浏览：722 订阅该版

我的需求是，按一下按键灯只闪烁一次，解决轮询读取按键中抖动的问题，理论上线程2获得互斥量期间线程1不是不会识别的吗？为什么还会出现抖动识别问题，按一下灯还是会闪2-3次呢？
如下是我代码：
```c
/* USER CODE BEGIN 0 */
static void thread1_entry(void *parameter)
{
	while(1)
	{
				rt_err_t result;
				result = rt_mutex_take(mutex, RT_WAITING_FOREVER);

if (result == RT_EOK)
			{
						while(1)
						{
	
							if(!HAL_GPIO_ReadPin(GPIOE, GPIO_PIN_4))
							{	
								rt_mutex_release(mutex);
								rt_thread_mdelay(200);
								break;
							}
			//				rt_thread_mdelay(100);
							
						}
					
			}
}

static void thread2_entry(void *parameter)
{
	while(1)
	{
		rt_err_t result;
	result = rt_mutex_take(mutex, RT_WAITING_FOREVER);

if (result == RT_EOK)
			{
				HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_RESET);
								rt_thread_mdelay(500);
							HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_SET);
								rt_thread_mdelay(500);
			//	HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_5);
		
					rt_mutex_release(mutex);
			//	rt_thread_mdelay(400);
			}
		}
	
}

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
	/* 创建互斥锁 */
	rt_err_t result;
	
    mutex = rt_mutex_create("mutex", RT_IPC_FLAG_PRIO);
    if (mutex == RT_NULL)
    {
        rt_kprintf("create dynamic mutex failed.\n");
        return -1;
    }
		
		 result = rt_event_init(&event, "event", RT_IPC_FLAG_PRIO);
    if (result != RT_EOK)
    {
        rt_kprintf("init event failed.\n");
        return -1;
    }

/* Initialize all configured peripherals */
  MX_GPIO_Init();
  /* USER CODE BEGIN 2 */
		/* 创建线程 1，名称是 thread1，入口是 thread1_entry*/
    Key_scanf = rt_thread_create("thread1",
                            thread1_entry, RT_NULL,
                            THREAD_STACK_SIZE,
                            THREAD_PRIORITY, THREAD_TIMESLICE);

/* 如果获得线程控制块，启动这个线程 */
				    if (Key_scanf != RT_NULL)
        rt_thread_startup(Key_scanf);
		
		    Key_handler = rt_thread_create("thread2",
                            thread2_entry, RT_NULL,
                            THREAD_STACK_SIZE,
                            THREAD_PRIORITY, THREAD_TIMESLICE);

/* 如果获得线程控制块，启动这个线程 */
    if (Key_handler != RT_NULL)
        rt_thread_startup(Key_handler);

/* USER CODE END 2 */

/* Infinite loop */
  /* USER CODE BEGIN WHILE */

/* USER CODE END 3 */
}
```
```c
/* USER CODE BEGIN 0 */
static void thread1_entry(void *parameter)
{
	while(1)
	{
				rt_err_t result;
				result = rt_mutex_take(mutex, RT_WAITING_FOREVER);