AVR-Chat

I used the following code for GCC on a 16-MHz Mega-8. It seems to work
fine for me. I also used the same code on an 8-MHz Mega-16, but setting
TCNT0 to 131 (125000 counts/sec and 256 - 125 = 131)

gTickCount gets incremented once every millisecond.

volatile uns16 gTickCount = 0;

/***********************************************************************
****/
/**
*  Timer 0 interrupt handler
*/

SIGNAL(SIG_OVERFLOW0)        /* signal handler for tcnt0 overflow
interrupt */
{
    gTickCount++;

    // We want our timer tick to interrupt once a millisecond.
    // If we use 16 MHz/64 then we get 250000 counts/second. So setting
    // things up to overflow after 250 will give us 1000
overflows/second
    //
    // 256 - 250 = 6

    TCNT0 = 6;

} // Timer 0 Overflow

/***********************************************************************
****/
/**
*  InitTimer
*/

void InitTimer( void )
{
    TCCR0 = ( 0 << CS02 ) | ( 1 << CS01 ) | ( 1 << CS00 ); // Divide by
64
    TCNT0 = 0;

    // Enable Timer 0 interrupt

    timer_enable_int( BV( TOIE0 ));

    sei();

} // InitTimer

> -----Original Message-----
> From: Larry Barello [mailto:yahoo@barello.net] 
> Sent: Monday, March 22, 2004 1:35 PM
> To: AVR-Chat@yahoogroups.com
> Subject: RE: [AVR-Chat] Delay
> 
> 
> What compiler?  What CPU clock speed?  What CPU clock speed 
> does the compiler think you are using?
> 
> -----Original Message-----
> From: ereihani
> 
> 
> HI!
> For making delays I use delay_ms().
> But this doesn't work be cause when I use delay_ms(1000) for 
> 1 s delay i get about 8s delay. I used Timer 0 but it did't 
> work too! I first made 250us.Then in a for loop for 4 times i 
> made 1ms then 1s. But I had the same problem! Please guide me.
> Regards:
> Ehsan Reihani
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>