Ok, I understand that (I do know what are interrupts for and why they are disabled in time critical sections). I do not understand why delayMicroseconds acts differently depending on interrupts being disabled or enabled. Declaration of delayMicrosections for SAM is quite simple (from wiring.c):
void delayMicroseconds( uint32_t us )
{
uint32_t start = micros();
while ((micros() - start) < us)
;
}
It did not change since 1.5.1r2.
Do you have an idea, what the solution could be?
Leo
PS if I can contribute in any way, let me know.