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timer interrupt

Hi, i want to tune my timer ISR to 20hz , 1/20 sec , i dont know what are the values to be loaded with the timer.

 void timer0_isr (void) interrupt 1 using 1
{
unsigned i;
 TR0 = 0; /* stop timer 0 */
TL0 = ;
TH0 = ;
TR0 = 1;
overflow_count++;
}

Parents

0 Ahmed saleh over 18 years ago in reply to Kalib Rahib

thanks i got the idea
is this correct to make ISR at 15ms ~ 15hz ?


static unsigned long overflow_count = 0;

void timer1_ISR (void) interrupt 3
{
overflow_count++;   /* Increment the overflow count */
}

/*------------------------------------------------
MAIN C function
------------------------------------------------*/
void main (void)
{

Set the Timer1 Run control bit.
--------------------------------------*/
TMOD &= 0xF0; // Clear all T0 bits (T1 left unchanged)
TMOD |= 0x01;
TH1 = 0xC5;
TL1 = 0x68;
ET1 = 1;                      /* Enable Timer 1 Interrupts */
TR1 = 1;                      /* Start Timer 1 Running */
EA = 1;                       /* Global Interrupt


while (1)
  {
  }
}

Reply

0 Ahmed saleh over 18 years ago in reply to Kalib Rahib

thanks i got the idea
is this correct to make ISR at 15ms ~ 15hz ?


static unsigned long overflow_count = 0;

void timer1_ISR (void) interrupt 3
{
overflow_count++;   /* Increment the overflow count */
}

/*------------------------------------------------
MAIN C function
------------------------------------------------*/
void main (void)
{

Set the Timer1 Run control bit.
--------------------------------------*/
TMOD &= 0xF0; // Clear all T0 bits (T1 left unchanged)
TMOD |= 0x01;
TH1 = 0xC5;
TL1 = 0x68;
ET1 = 1;                      /* Enable Timer 1 Interrupts */
TR1 = 1;                      /* Start Timer 1 Running */
EA = 1;                       /* Global Interrupt


while (1)
  {
  }
}

Children

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