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Timer interrupt programming

vead

Nov 27, 2011
473
Joined
Nov 27, 2011
Messages
473
Hello

I have written program to set timer interrupt on 8051 microconroller. I want to set interuupt for 50 ms

Fosc = 11.0592Mhz
tick = 12/11.0592M = 1.085069444us = 1.085us
Interrupt time = 60 ms
60,000*1.085= 55299
65536-55299= 10237 =ox27FD
Code:
#include<reg51.h>
 
sbit LED = P1^0; 
 
int main(void)
{
/* Make all ports zero */
   P0 = 0x00; 
   P1 = 0x00; 
   P2 = 0x00; 
   P3 = 0x00;
 
   TR0 = 0;                 //turn Off Timer 0
   TF0 = 0;                 //Clear the interrupt flag
   TMOD = 0x01;             //Set timer0 in mode 1
   TH0 = 0x27;               //Load the timer value
   TL0 = 0xFD; 
   ET0 = 1;                /* Enable Timer0 interrupts */ 
   EA  = 1;                /* Global interrupt enable */
   TR0 = 1;                //turn ON Timer 0 
 
   while(1)
    {
        
    }
}
 
void timer(void) interrupt 1 
  {
       LED=~LED;               /*toggle LED on interrupt */
       TH0=0x48;                /* initial values loaded to timer */
       TL0=0x01;
  }

I am setting interrupt for 60 ms. does it means interrupt will generate after 60 ms second,

Does it happen, Led blink after every 60 ms and for 60 ms

I am not sure weather my interrupt calculation is correct or wrong?
 
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