posted January 13, 2002 08:50            

Salvo v2.2.1 and earlier.

Description of Problem

If a task waits an event less frequently than the event is signaled, then the task will never yield to the scheduler, and no other tasks can run.

For example, if a task waits a semaphore that is signaled at a very high rate (e.g. from within an ISR), the task will only yield back to the scheduler when the semaphore has "fallen back to zero."

Suggested Workaround

Add a call to OS_Yield() immediately after OS_WaitXyz(), like this:

code:

---

for (;;) {
  OS_WaitSem(SEM_NAME, label1);
  OS_Yield(label2);
  …
}

---

Fixed In