Why event flag related functions does not work correctly outside of tasks in keil rtx? - rtos

Question

As you know event flags are very useful (e.g. let task running),but unfortunately their control functions (os_evt_clr/set/wait) does not work outside of tasks bodies correctly(e.g. in interrupt handling functions). For alternative i used a variable ,I initialized it in Interrupt handler when needed ,then used it on another task to running a os_evt_set() function for let MCU entering a task.
bool Instance_Variable;
Interrupt_Handler()
{
if(xxxx)
Instance_Variable=1
}
//--------------------------
Secondary_Task()
{
//This is frequently run task
if(Instance_Variable==1)
{
os_evt_set (0x0001, Primary_Task_ID);
Instance_Variable=0;
}
}
//--------------------------
Primary_Task()
{
Result = os_evt_wait_or (0x0001, 0xFFFF);
//Task's body
os_evt_clr (0x0001, Primary_Task_ID);
}
Any better approach?WBR.

Answer 1

You can't use function prefixed with os_ inside ISR. Usage hints from RTX documentation:
Functions that begin with os_ can be called from a task, but not from an interrupt service routine.
Functions that begin with isr_ can be called from an IRQ interrupt service routine but not from a task.
This code will work:
Interrupt_Handler() {
if(xxxx) {
isr_evt_set (0x0001, Primary_Task_ID);
}
}
//--------------------------
Primary_Task() {
Result = os_evt_wait_or (0x0001, 0xFFFF);
//Task's body
os_evt_clr (0x0001, Primary_Task_ID);
}