为什么Ucosiii移植完后只在空闲任务中运行？

UCOSIII 移植完后，只在空闲任务中运行，不启动其他任务？ //开始任务
OSTaskCreate((OS_TCB * )&StartTaskTCB, //èÎÎñ¿ØÖÆ¿é
(CPU_CHAR * )"start task", //èÎÎñÃû×Ö
(OS_TASK_PTR )start_task, //èÎÎñoˉêy
(void * )0, //′«μY¸øèÎÎñoˉêyμÄ2Îêy
(OS_PRIO )START_TASK_PRIO, //èÎÎñóÅÏ輶
(CPU_STK * )&START_TASK_STK[0], //èÎÎñ¶ÑÕ»»ùμØÖ·
(CPU_STK_SIZE)START_STK_SIZE/10, //èÎÎñ¶ÑÕ»éî¶èÏTλ
(CPU_STK_SIZE)START_STK_SIZE, //èÎÎñ¶ÑÕ»′óD¡
(OS_MSG_QTY )0, //èÎÎñÄú2¿ÏûÏ￠¶óáDÄü1»½óêÕμÄ×î′óÏûÏ￠êyÄ¿,Îa0ê±½ûÖ1½óêÕÏûÏ￠
(OS_ tiCK )0, //μ±ê1Äüê±¼äƬÂÖ×aê±μÄê±¼äƬ3¤¶è￡¬Îa0ê±ÎaĬèÏ3¤¶è￡¬
(void * )0, //óû§213äμÄ′æ′￠Çø
(OS_OPT )OS_OPT_TASK_STK_CHK|OS_OPT_TASK_STK_CLR, //èÎÎñÑ¡Ïî
(OS_ERR * )&err); //′æ·Å¸Ãoˉêy′íÎóê±μÄ·μ»ØÖμ
OS_CRITICAL_EXIT(); //íË3öáù½çÇø
OSStart(&err); //¿aÆôUCOSIII
while (1);
//蜂鸣器任务
OSTaskCreate((OS_TCB * )&BuzzerTaskTCB,
(CPU_CHAR * )"Buzzer task",
(OS_TASK_PTR )Buzzer_task,
(void * )0,
(OS_PRIO )BUZZER_TASK_PRIO,
(CPU_STK * )&BUZZER_TASK_STK[0],
(CPU_STK_SIZE)BUZZER_STK_SIZE/10,
(CPU_STK_SIZE)BUZZER_STK_SIZE,
(OS_MSG_QTY )0,
(OS_TICK )0,
(void * )0,
(OS_OPT )OS_OPT_TASK_STK_CHK|OS_OPT_TASK_STK_CLR,
(OS_ERR * )&err);

//LED任务
OSTaskCreate((OS_TCB * )&LedTaskTCB,
(CPU_CHAR * )"led task",
(OS_TASK_PTR )Led_task,
(void * )0,
(OS_PRIO )LED_TASK_PRIO,
(CPU_STK * )&LED_TASK_STK[0],
(CPU_STK_SIZE)LED_STK_SIZE/10,
(CPU_STK_SIZE)LED_STK_SIZE,
(OS_MSG_QTY )0,
(OS_TICK )0,
(void * )0,
(OS_OPT )OS_OPT_TASK_STK_CHK|OS_OPT_TASK_STK_CLR,
(OS_ERR * )&err);
请大侠指导，跪谢！