Re: [avr-gcc-list] Problem with timer0 overflow interrupt in c language..

[Clemens Koller]

Sach schrieb:
> Hi friends,
> I m programming with WinAVR for ATMega32 8-bit RISC from atmel.
> I have tried to write timer overflow interrupt and LED toggle everytime when
> timer0 overflows. In this code i have not got the output result. So please
> help me with this issue. Here the code that i have written is given below:
>
>
> #include <avr\io.h>
> #include <avr\interrupt.h>
>
> void main(void)
> {
>         SP    = 0x085F;
>         TCCR0 = (1<<CS02)|(1<<CS00);
>         TIFR = 1<<TOV0;
>         TIMSK = 1<<TOIE0;
>         DDRB = 0xFF;
>         sei();
>         while(1);
> }
>
>
> ISR (TIMER0_OVF_vect)
> {       
>         cli();
>         PORTB = ~PORTB; // Toggle pins on Port B
> }

Tried to remove the cli(); ?
You won't get any interrupts after cli();

And try one of so many examples out there.
Here is another one from some code of mine:
(not compile tested...):

#include <...>

int timer0;

void timer0_init(void)
{
        timer0 = 0;
        /* timer0 prescaler = clk/1042 -> 11059200Hz / 1024 = 10800Hz per 
increment */
        /* overflow every 256 ticks = 42.1875Hz = 23.7037ms an interrupt */
        TCCR0B |= _BV(CS00) | _BV(CS02);
        TCNT0 = 0;
        TIMSK0 |= _BV(TOIE0);
        /* and take care that the timers are not in power down mode */
}

ISR(TIMER0_OVF_vect)
{
        /* don't use cli(); here */
        timer0++; /* or toggle your LED */
}

int main(void ) {
        PORTB = 0xff;   /* i.e. all to output */
        timer0_init();
        sei();
        /* do something else here */
}



Well... good luck...

Regards,
--
Clemens Koller
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