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fermionboson
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period
PostPosted: Fri Dec 14, 2007 10:01 am     Reply with quote
Hello, body:
I use timer2 as the interruption, but the actual period is more than the theoretic period.
For example, Fosc=8MHZ
The periode de Timer2=1/(8Mhz/4/2)=1us, but i have got about 44us, could anyone tell me why and how to avoid this problem?
Thx!

Code:
#include<18f458.h>
#device ICD=TRUE
#use delay (clock=8000000)
#fuses HS, NOWDT, NOPROTECT
#int_timer2
void IT_handler(void) {
     
    static int x=0;
   if (x==0) {
       output_bit(PIN_D4,1);
        x=1;
   } else {
       output_bit(PIN_D4,0);
        x=0;
   }
}
void main(void)
{
   
    setup_timer_2(T2_DIV_BY_1,1,1);
    set_timer2(0);
    enable_interrupts (GLOBAL);
    enable_interrupts(INT_TIMER2);
   
    while(TRUE);
   
}
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Dec 14, 2007 11:14 am     Reply with quote
See Ttlemah's explanation in this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=32787
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