RE: [avr-gcc-list] for loop problem

[Jeff McBride]

Why is the for loop and delay necessary at all? For something like this,
I would usually just use:

while(Timeout_Flag =! 0xFF && Element_Pulse_Flag != 0xFF);
// now do whatever needs to be done when flags get set

Am I missing something??

Jeff

On Fri, 17 Jan 2003, Adrian Cottle wrote:

> I have tryed changing the flag rto static volatile and volatile. this seems 
> to have corrected the UART loop problem but not the other loop problem
> 
> while(Timeout_Flag != 0xFF && Element_Pulse_Flag != 0xFF)
>   {
>       int i;
>       for(i=0;i<10;i++)
>       {
>       //msdelay(1);
>       }
> 
>   }
> 
> this still needs the delay in to work
> 
> any idea?
> 
> thanks
> 
> adrian
> 
> 
> Adrian,
> 
> > I have the function below (well part of it) and it waits in a loop until
> > the UART flag is flagged.  If i put a 100ms delay in or do something like 
> > send a byte to the uart it works fine, but as soon as i leave a empty for 
> > loop it crashed and needs resettting.
> ...
> > int Pulse_Handler(void)
> > {
> > int i;
> > uart_send_byte(33);
> >   while(UART_Flag == 0)
> >   {
> >     msdelay(1);
> >  //uart_send_byte(46);
> >   }
> >   UART_Flag = 0 ;                           
> >   uart_send_byte(85);
> 
> You need to define UART_Flag as volatile. If you look at the generated code 
> you can see that without volatile it checks only once for UART_Flag and 
> runs than into an endless loop. With the volatile you can see that the 
> compare is included into the loop.
> 
> Volkmar
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