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Unscheduled Scheduler Stoppage

Posted by John W. on May 16, 2006

After my target runs for awhile - I get a stoppage:

My call stack looks like this:


In main:

// shouldn't get past this point unless a task calls vTaskEndScheduler()

// Note - I have a breakpoint on this first NOOP but it doesn't stop there

while (1) {
// I have a breakpoint on the 2nd NOOP (just above) and the debugger stops here.

// turn Debug LED's on:
asm("bis.b #0x80,&0x1d");
asm("bis.b #0x01,&0x1d");

I run the Idle Hook as well - this (crash) doesn't always happen either - but I assume all of my targets will eventually fail.

What are some reasons this can happen? I know this may seem a bit nebulous - but the Scheduler is exiting (even though the vTaskEndScheduler() function) - isn't being called.

It seems that somehow the return address from the
vTaskStartScheduler(); call is getting popped into the PC and executed - or at least an address+2 or something.

From my linker map file:

Relative segment, address: 3082 - 3085 (0x4 bytes), align: 1
Segment part 5. Intra module refs: pvPortMalloc
===== =======
xEnd 3082

I'm using heap_2.c as my memory manager:

/* xEnd is used to mark the end of the list of free blocks. */

I'm also saying that the IdleTask & Hook should yield - it seems this problem may be occurring during that.

Thanks In Advance,
John W.

RE: Unscheduled Scheduler Stoppage

Posted by Nobody/Anonymous on May 16, 2006
I understand not the sentense "I'm also saying that the IdleTask & Hook should yield". The idle task must always be in a ready state and not blocked so just yield must be ok. Sorry to state obvious but sometimes it can help. Otherwise is the idle task stack causing a problem under some interrupt conditions?

RE: Unscheduled Scheduler Stoppage

Posted by John W. on May 16, 2006
Idle task doesn't block - correct.

I think the Idle Task Stack may be causing a problem under some interrupt conditions - yes.


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