实例：消息队列简单应用 - 曲径通幽论坛

#include "includes.h"

#define N_MESSAGES       128

#define TASK_STK_SIZE                 512

  OS_STK    StartTaskStk[TASK_STK_SIZE];
  OS_STK        MyTaskStk[TASK_STK_SIZE];
  OS_STK        YouTaskStk[TASK_STK_SIZE];

  INT16S key;
  INT8U   err;
  INT8U   y = 0;
  OS_EVENT *Str_Q;

  char *ss;
  char *s100;
  char *s;
  char *s500;

  void *MsgGrp[N_MESSAGES];     /*消息数组,消息数组存放着各消息的指针*/

void StartTask(void *data);
void MyTask(void *data);
void YouTask(void *data);

void main (void)
{

PC_DispClrScr(DISP_FGND_WHITE + DISP_BGND_BLACK);
OSInit();
PC_DOSSaveReturn();
PC_VectSet(uCOS, OSCtxSw);

Str_Q = OSQCreate( &MsgGrp[0], N_MESSAGES ); /*建立消息队列,参数为消息指针数组的首址

                                                                                                 和数组长度*/

OSTaskCreate(StartTask, (void *)0, &StartTaskStk[TASK_STK_SIZE - 1], 0);
OSStart();

}

void StartTask(void *pdata)
{
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif

pdata = pdata;                                         /* Prevent compiler warning                 */

OS_ENTER_CRITICAL();
PC_VectSet(0x08, OSTickISR);                           /* Install uC/OS-II's clock tick ISR        */
PC_SetTickRate(OS_TICKS_PER_SEC);                      /* Reprogram tick rate                      */
OS_EXIT_CRITICAL();

OSStatInit();                                          /* Initialize uC/OS-II's statistics         */

OSTaskCreate(MyTask,(void *)0, &MyTaskStk[TASK_STK_SIZE - 1], 3);

OSTaskCreate(YouTask,(void *)0, &YouTaskStk[TASK_STK_SIZE - 1], 4);

s = "how many times this str can receive?";

for(;;)
{
if( OSTimeGet()>100 && OSTimeGet()<500 )
{
   s100 = "The value of OSTime is between 100 and 500";

   OSQPostFront( Str_Q, s100 );            /*后进先出的方式安插消息*/

   s = "which task received this str?";

   OSQPostFront( Str_Q, s );                  /*后进先出的方式安插消息*/

}

if( OSTimeGet()>5000 && OSTimeGet()<5500 )
{
   s500 = "The value of OSTime is between 5000 and 5500";

   OSQPostFront( Str_Q,s500 );            /*后进先出的方式安插消息*/
}

if( PC_GetKey(&key) == TRUE )
{
   if( key == 0x1B )
   {
    PC_DOSReturn();
    }

}
     OSTimeDlyHMSM(0,0,1,0);
  }

}
void MyTask (void *pdata)
{
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif

pdata = pdata;

for (;;)
   {
   ss = OSQPend(Str_Q,0,&err);            /*请求消息*/

   PC_DispStr(10,++y,ss,DISP_BGND_BLACK + DISP_FGND_WHITE);

   OSTimeDlyHMSM(0,0,1,0);

   }

}

void YouTask(void *pdata)
{
#if OS_CRITICAL_METHOD == 3
OS_CPU_SR cpu_sr;
#endif

pdata = pdata;

for (;;)
   {
   ss = OSQPend(Str_Q,0,&err);                   /*请求消息*/

    PC_DispStr(10,10,ss,DISP_BGND_BLACK + DISP_FGND_WHITE);

   OSTimeDlyHMSM(0,0,1,0);
}

}