During initialization, µC/OS-III creates a minimum of two (2) internal tasks (OS_IdleTask() and OS_TickTask()) and, three (3) optional tasks (OS_StatTask(), OS_TmrTask() and OS_IntQTask()). The optional tasks are created based on the value of compile-time #defines found in os_cfg.h.
OS_CFG_STAT_TASK_EN enables OS_StatTask()
OS_CFG_TMR_EN enables OS_TmrTask()
OS_CFG_ISR_POST_DEFERRED_EN enables OS_IntQTask()