执行完? OSIntExit(); 后，再进行任务调度，可是那两个任务都是在等待信号量啊，难道执行完中断函数后会释放一个信号量吗？

a598009273 · 发表于 2014-4-18 17:39:17

[mw_shl_code=c,true]/* ********************************************************************************************************* * * * 火牛开发板uCOSII + STM32V3.4固件函数库+USART1驱动（实例二） * MAIN 文件 * 创建人：LJ128 * 修改时间：2010年12月11日 * * ********************************************************************************************************* */ #include "includes.h" static OS_STK App_TaskStartStk[APP_TASK_START_STK_SIZE]; // TaskStart 任务堆栈 static void App_TaskStart(void* p_arg); // 声明 TaskStart 函数 static OS_STK App_TaskPrintfStk[APP_TASK_PRINTF_STK_SIZE]; // TaskPrintf 任务堆栈 static void App_TaskPrintf(void* p_arg); // 声明 TaskPrintf 函数 void LED1234_ON_OFF(CPU_INT08U Num); // 声明流水灯函数 OS_EVENT *Mutex_USART1; // 定义互斥型事件 /* ********************************************************************************************************* main() ********************************************************************************************************* */ int main(void) { OSInit(); SysClock_Init(); /* 初始化系统外设、 CPU 时钟，仅此而已 */ /* 建立系统的第一个任务 */ OSTaskCreateExt(App_TaskStart, (void *) 0, (OS_STK *) &App_TaskStartStk[APP_TASK_START_STK_SIZE - 1], APP_TASK_START_PRIO, APP_TASK_START_PRIO, (OS_STK *) &App_TaskStartStk[0], APP_TASK_START_STK_SIZE , (void *) 0, OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR ); OSStart(); /* 开始任务调度 */ return (0); } /* ********************************************************************************************************* 系统的第一个任务，负责开OS时钟，建立其他任务 ********************************************************************************************************* */ static void App_TaskStart(void* p_arg) { INT8U err; INT8U i; p_arg = p_arg; /* 初始化 OS 时钟 */ OS_CPU_SysTickInit(); /* 统计任务 */ #if (OS_TASK_STAT_EN > 0) OSStatInit(); #endif Mutex_USART1 = OSMutexCreate(USART1_MUTEX_PRIO, &err); // 建立USART1互斥型信号量 // 建立打印任务 OSTaskCreateExt(App_TaskPrintf, (void *) 0, (OS_STK *) &App_TaskPrintfStk[APP_TASK_PRINTF_STK_SIZE - 1], APP_TASK_PRINTF_PRIO, APP_TASK_PRINTF_PRIO, (OS_STK *) &App_TaskPrintfStk[0], APP_TASK_PRINTF_STK_SIZE , (void *) 0, OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR ); /* 初始化外设 */ BSP_Init(); while (1) { for(i = 0 ; i < 4; i++){ LED1234_ON_OFF(i); OSTimeDlyHMSM(0,0,1,0); // 延时一秒 OSMutexPend(Mutex_USART1, 0, &err); // 等待信号量 USART1_Printf("******任务一输出********\r\n"); OSMutexPost(Mutex_USART1); // 释放信号量 } } } /* ********************************************************************************************************* 打印线程，将串口1接收到的数据打印出来 ********************************************************************************************************* */ static void App_TaskPrintf(void* p_arg) { INT8U err; INT8U temp; p_arg = p_arg; while (1) { OSTaskSuspend(OS_PRIO_SELF); // 先将任务挂起，在串口接收中断中恢复任务 OSMutexPend(Mutex_USART1, 0, &err); // 等待信号量 while(USART1_GetByte(&temp)){ // 如果串口接收到数据打印出来 USART1_SendByte(temp); } OSMutexPost(Mutex_USART1); // 释放信号量 } } /* ********************************************************************************************************* ********************************************************************************************************* * uC/OS-II APP HOOKS ********************************************************************************************************* ********************************************************************************************************* */ #if (OS_APP_HOOKS_EN > 0) /* ********************************************************************************************************* * TASK CREATION HOOK (APPLICATION) * * Description : This function is called when a task is created. * * Argument : ptcb is a pointer to the task control block of the task being created. * * Note : (1) Interrupts are disabled during this call. ********************************************************************************************************* */ void App_TaskCreateHook(OS_TCB* ptcb) { } /* ********************************************************************************************************* * TASK DELETION HOOK (APPLICATION) * * Description : This function is called when a task is deleted. * * Argument : ptcb is a pointer to the task control block of the task being deleted. * * Note : (1) Interrupts are disabled during this call. ********************************************************************************************************* */ void App_TaskDelHook(OS_TCB* ptcb) { (void) ptcb; } /* ********************************************************************************************************* * IDLE TASK HOOK (APPLICATION) * * Description : This function is called by OSTaskIdleHook(), which is called by the idle task. This hook * has been added to allow you to do such things as STOP the CPU to conserve power. * * Argument : none. * * Note : (1) Interrupts are enabled during this call. ********************************************************************************************************* */ #if OS_VERSION >= 251 void App_TaskIdleHook(void) { } #endif /* ********************************************************************************************************* * STATISTIC TASK HOOK (APPLICATION) * * Description : This function is called by OSTaskStatHook(), which is called every second by uC/OS-II's * statistics task. This allows your application to add functionality to the statistics task. * * Argument : none. ********************************************************************************************************* */ void App_TaskStatHook(void) { } /* ********************************************************************************************************* * TASK SWITCH HOOK (APPLICATION) * * Description : This function is called when a task switch is performed. This allows you to perform other * operations during a context switch. * * Argument : none. * * Note : 1 Interrupts are disabled during this call. * * 2 It is assumed that the global pointer 'OSTCBHighRdy' points to the TCB of the task that * will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCur' points to the * task being switched out (i.e. the preempted task). ********************************************************************************************************* */ #if OS_TASK_SW_HOOK_EN > 0 void App_TaskSwHook(void) { } #endif /* ********************************************************************************************************* * OS_TCBInit() HOOK (APPLICATION) * * Description : This function is called by OSTCBInitHook(), which is called by OS_TCBInit() after setting * up most of the TCB. * * Argument : ptcb is a pointer to the TCB of the task being created. * * Note : (1) Interrupts may or may not be ENABLED during this call. ********************************************************************************************************* */ #if OS_VERSION >= 204 void App_TCBInitHook(OS_TCB* ptcb) { (void) ptcb; } #endif #endif /****************************************** * * LED 流水灯 * ****************************************/ void LED1234_ON_OFF(CPU_INT08U Num) { switch (Num) { case 0: GPIO_SetBits(GPIOD, GPIO_Pin_8); GPIO_ResetBits(GPIOD, GPIO_Pin_9); GPIO_ResetBits(GPIOD, GPIO_Pin_10); GPIO_ResetBits(GPIOD, GPIO_Pin_11); break; case 1: GPIO_ResetBits(GPIOD, GPIO_Pin_8); GPIO_SetBits(GPIOD, GPIO_Pin_9); GPIO_ResetBits(GPIOD, GPIO_Pin_10); GPIO_ResetBits(GPIOD, GPIO_Pin_11); break; case 2: GPIO_ResetBits(GPIOD, GPIO_Pin_8); GPIO_ResetBits(GPIOD, GPIO_Pin_9); GPIO_SetBits(GPIOD, GPIO_Pin_10); GPIO_ResetBits(GPIOD, GPIO_Pin_11); break; case 3: GPIO_ResetBits(GPIOD, GPIO_Pin_8); GPIO_ResetBits(GPIOD, GPIO_Pin_9); GPIO_ResetBits(GPIOD, GPIO_Pin_10); GPIO_SetBits(GPIOD, GPIO_Pin_11); break; default: break; } } [/mw_shl_code]

[mw_shl_code=c,true]static void App_TaskPrintf(void* p_arg) [/mw_shl_code] static void App_TaskStart(void* p_arg) 我的理解是先执行任务static void App_TaskStart(void* p_arg)，然后碰到延时一秒转而去执行static void App_TaskPrintf(void* p_arg)这个任务，执行到任务挂起时，去执行TaskStart开始任务，此时碰到OSMutexPend(Mutex_USART1, 0, &err);等待信号量，此时两个任务都不执行，等待串口中断来临，当串口中断来了时
void USART1_IRQHandler(void)
{
OS_CPU_SR cpu_sr;

OS_ENTER_CRITICAL(); //保存全局中断标志,关总中断/* Tell uC/OS-II that we are starting an ISR*/
OSIntNesting++;
OS_EXIT_CRITICAL(); //恢复全局中断标志

if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET){ // 如果是串口接收中断
USART1_RXLoop(USART_ReceiveData(USART1)); // 将数据放入环形队列
OSTaskResume(APP_TASK_PRINTF_PRIO);
}

OSIntExit();
}
这是串口中断函数，执行完 OSIntExit(); 后，再进行任务调度，可是那两个任务都是在等待信号量啊，难道执行完中断函数后会释放一个信号量吗？