AW: [avr-gcc-list] Bug in avr-libc or?

[Andreas Trenkwalder]

Hello,

> What happen was that the variable in the while loop was 
> copied into a register and the while loop did test the 
> register instead of the variable.
> Thereby never detecting any change of the variable done in 
> the interrupt routine.
> 

Try to declare your variable as volatile:
 
volatile uint8_t var;

This indicates that a variable may be changed in a way which is
unpredictable by analysing the normal program flow (such as variable which
may be changed by an interrupt handler). 

Regards, 
Andreas