Lpc2000

How do i calculate the time?
I have the example you can see herunder.

In the interrupt routine the TOMR0 is set to 149999 because it 
should be 10mSec.

But how do i calculate the number? if i need a another time.

-------------------------------------------------------------------

void tc0 (void) __irq  
{
  T0MR0 = 149999;                // 10mSec = 150.000-1 counts
  T0IR        = 1;               // Clear interrupt flag
  VICVectAddr = 0;               // Acknowledge Interrupt

	if ((IO1SET & 0xff000000) == 0xFF000000)
		IO1CLR = 0xFF000000;
	else
		IO1SET = 0xFF000000;	
}

/* Setup the Timer Counter 0 Interrupt */
void init_timer (void) 
{
  T0MR0 = 149999;                   // 10mSec = 150.000-1 counts

  T0MCR = 3;                        // Interrupt and Reset on MR0
  T0TCR = 1;                        // Timer0 Enable
  VICVectAddr0 = (unsigned long)tc0;// set interrupt vector in 0
  VICVectCntl0 = 0x20 | 4;          // use it for Timer 0 Interrupt
  VICIntEnable = 0x00000010;        // Enable Timer0 Interrupt
}

int main (void)  
{
	unsigned int i;
	IO1DIR = 0xFFff0000;
	init_timer();
	while(1) 
	{
		IO1SET = 0x00FFffff;	
		for (i = 0 ; i < 1000000 ; i++ ){}		
		IO1CLR = 0x00FFffff;	
		for (i = 0 ; i < 1000000 ; i++ ){}		
	};
	return 0;
}

The formula is:
   
  peripheral_frequency=oscillator_frequency*pll_multiplier(if pll is enabled)/vpb_dividor
   
  So if your oscillator_frequency is 12MHz, pll_multiplier is 5 and vpb_dividor is 4, the peripheral_frequency would be 15MHz. So for 10msec, the count would be:
   
  Count = peripheral_frequency * time_required
           =   15,000,000 * .01
           =   150,000
   
  So the count to be loaded in T0MR0 is 150000.

teddyroskvist <thr@...> wrote:
  How do i calculate the time?
I have the example you can see herunder.

In the interrupt routine the TOMR0 is set to 149999 because it 
should be 10mSec.

But how do i calculate the number? if i need a another time.

-------------------------------------------------------------------

void tc0 (void) __irq  
{
  T0MR0 = 149999;                // 10mSec = 150.000-1 counts
  T0IR        = 1;               // Clear interrupt flag
  VICVectAddr = 0;               // Acknowledge Interrupt

      if ((IO1SET & 0xff000000) == 0xFF000000)
            IO1CLR = 0xFF000000;
      else
            IO1SET = 0xFF000000;      
}

/* Setup the Timer Counter 0 Interrupt */
void init_timer (void) 
{
  T0MR0 = 149999;                   // 10mSec = 150.000-1 counts

  T0MCR = 3;                        // Interrupt and Reset on MR0
  T0TCR = 1;                        // Timer0 Enable
  VICVectAddr0 = (unsigned long)tc0;// set interrupt vector in 0
  VICVectCntl0 = 0x20 | 4;          // use it for Timer 0 Interrupt
  VICIntEnable = 0x00000010;        // Enable Timer0 Interrupt
}

int main (void)  
{
      unsigned int i;
      IO1DIR = 0xFFff0000;
      init_timer();
      while(1) 
      {
            IO1SET = 0x00FFffff;      
            for (i = 0 ; i < 1000000 ; i++ ){}            
            IO1CLR = 0x00FFffff;      
            for (i = 0 ; i < 1000000 ; i++ ){}            
      };
      return 0;
}





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[Non-text portions of this message have been removed]

Perfect.

Thank you.

--- In lpc2000@yahoogroups.com, Jack Key <jockey1111111@...> wrote:
>
> The formula is:
>    
>   peripheral_frequency=oscillator_frequency*pll_multiplier(if pll 
is enabled)/vpb_dividor
>    
>   So if your oscillator_frequency is 12MHz, pll_multiplier is 5 
and vpb_dividor is 4, the peripheral_frequency would be 15MHz. So 
for 10msec, the count would be:
>    
>   Count = peripheral_frequency * time_required
>            =   15,000,000 * .01
>            =   150,000
>    
>   So the count to be loaded in T0MR0 is 150000.
> 
> teddyroskvist <thr@...> wrote:
>   How do i calculate the time?
> I have the example you can see herunder.
> 
> In the interrupt routine the TOMR0 is set to 149999 because it 
> should be 10mSec.
> 
> But how do i calculate the number? if i need a another time.
> 
> -------------------------------------------------------------------
> 
> void tc0 (void) __irq  
> {
>   T0MR0 = 149999;                // 10mSec = 150.000-1 counts
>   T0IR        = 1;               // Clear interrupt flag
>   VICVectAddr = 0;               // Acknowledge Interrupt
> 
>       if ((IO1SET & 0xff000000) == 0xFF000000)
>             IO1CLR = 0xFF000000;
>       else
>             IO1SET = 0xFF000000;      
> }
> 
> /* Setup the Timer Counter 0 Interrupt */
> void init_timer (void) 
> {
>   T0MR0 = 149999;                   // 10mSec = 150.000-1 counts
> 
>   T0MCR = 3;                        // Interrupt and Reset on MR0
>   T0TCR = 1;                        // Timer0 Enable
>   VICVectAddr0 = (unsigned long)tc0;// set interrupt vector in 0
>   VICVectCntl0 = 0x20 | 4;          // use it for Timer 0 Interrupt
>   VICIntEnable = 0x00000010;        // Enable Timer0 Interrupt
> }
> 
> int main (void)  
> {
>       unsigned int i;
>       IO1DIR = 0xFFff0000;
>       init_timer();
>       while(1) 
>       {
>             IO1SET = 0x00FFffff;      
>             for (i = 0 ; i < 1000000 ; i++ ){}            
>             IO1CLR = 0x00FFffff;      
>             for (i = 0 ; i < 1000000 ; i++ ){}            
>       };
>       return 0;
> }
> 
> 
> 
> 
> 
>   SPONSORED LINKS 
>         Microcontrollers   Microprocessor   Intel 
microprocessors     Pic microcontrollers 
>     
> ---------------------------------
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> 
>     
>     Visit your group "lpc2000" on the web.
>     
>     To unsubscribe from this group, send an email to:
>  lpc2000-unsubscribe@yahoogroups.com
>     
>     Your use of Yahoo! Groups is subject to the Yahoo! Terms of 
Service. 

> 
>     
> ---------------------------------
>   
> 
> 
> 
> 		
> ---------------------------------
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> 
> [Non-text portions of this message have been removed]
>