In the ARTX, since the isr_evt_set can not be use in the __fiq function, I use the __swi function set the task instead. for exampal: void IsrSetFunction (void) __swi (8) { isr_evt_set (0x0001, tskMyTask); } void FIQ_Handler (void) __fiq { IsrSetFunction(); EXTINT = 0x00000002; // Clear the peripheral interrupt flag } But this way will do? You know, the ARTX using the swi to do something. 'Software interrupts 0-7 are used by the Advanced Real-Time Kernel (ARARM) and may not be used in your application.' So if I use the swi to set a task, this will occur some problem in ARTX?