FreeRTOS--二元信号量--任务间的同步

了解了二元信号量相关的一些概念，可以设计相关程序进行验证，基于STM32Cube生成的代码。

TASK1比TASK2优先级高，验证的初衷是TASK1S首先运行，而TASK2由于无法获取信号量而阻塞，5S之后TASK1释放信号量，TASK2获得信号量解除阻塞可以执行

由于FreeRTOS的新旧版本的API不同，导致现象不同于预期，问题就在xSemaphoreCreateBinary与vSemaphoreCreateBinary的区别

用vSemaphoreCreateBinary创建的二元信号量，初始值为“满”，因为创建的同时释放了信号量

1 #define vSemaphoreCreateBinary( xSemaphore ) 
2     { 
3         ( xSemaphore ) = xQueueGenericCreate( ( unsigned portBASE_TYPE ) 1, semSEMAPHORE_QUEUE_ITEM_LENGTH, queueQUEUE_TYPE_BINARY_SEMAPHORE ); 
4         if( ( xSemaphore ) != NULL ) 
5         { 
6             ( void ) xSemaphoreGive( ( xSemaphore ) ); 
7         } 
8     }

而xSemaphoreCreateBinary创建二元信号量，初始值为“空 ”

 1 osSemaphoreDef(myBinarySem);
 2  myBinarySemHandle = osSemaphoreCreate(osSemaphore(myBinarySem), 1);
 3 
 4   osThreadDef(vTask1, Task1, osPriorityAboveNormal, 0, 128);
 5   vTask1Handle = osThreadCreate(osThread(vTask1), NULL);
 6 
 7   /* definition and creation of vTask2 */
 8   osThreadDef(vTask2, Task2, osPriorityNormal, 0, 128);
 9   vTask2Handle = osThreadCreate(osThread(vTask2), NULL);
10 
11 /* Task1 function */
12 void Task1(void const * argument)
13 {
14 
15   /* USER CODE BEGIN Task1 */
16   static uint32_t cnt = 0;
17   /* Infinite loop */
18   for(;;)
19   {
20       Debug_Printf("Task1 is running,will be in the ready state!
");
21       osDelay(1000);
22       cnt++;
23       if(cnt == 5)
24       {
25           osSemaphoreRelease(myBinarySemHandle);
26           cnt = 0;
27       }
28   }
29   /* USER CODE END Task1 */
30 }
31 
32 /* Task2 function */
33 void Task2(void const * argument)
34 {
35   /* USER CODE BEGIN Task2 */
36   /* Infinite loop */
37   for(;;)
38   {
39       if(osOK == osSemaphoreWait(myBinarySemHandle,osWaitForever))
40               Debug_Printf("Task2 is running!
");
41       //osDelay(50);
42   }
43   /* USER CODE END Task2 */
44 }

当使用vSemaphoreCreateBinary如下打印信息，TASK2一开始并没有阻塞

当使用xSemaphoreCreateBinary如下打印信息,前5S,TAKS2一直被阻塞