Hy, i am trying to create a 250 microsecond task, just toggleing a  gpio pin from a port with out32 instructions.
The problem is with jitter, when I measure the jitter even a a 1milisecond impulse signal, its huge (average 500 micro-
seconds and the max is sometimes larger than the signal itself). i must be doing something wrong.
I set the clock period to 1 milisecond, set the priority to about 60 (larger than all of the user processes), but still 
the jitter is big, to big for a real time application, remember a want a 250 microsecond task. I even tried setting up a
 timer with a repetition interval of 250 microseconds using the same pretext as above but i had no good results.(same 
jitter) 
I would also like to add that i am using a AT91SAM9260-ek board for my target, and i`m using qnx neutrino 4.
How can i lower that jitter to a normal level, is there some kind of way to make a real-time below or even 1 milisecond 
without jitter?