delay using pic timer1

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luvuslim

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I am using pic16f877a timer1 to create 2ms delay. Crystal frequency is 20mhz.
I have loaded the value 55536 in tmr1 register to count 10000 but somehow its not working.
Code: 
void main()
{
TRISB=0;
  PORTB=0;
  GIE_BIT=1;
  PEIE_BIT=1;
  T1CON=0X00;
  TMR1IE_BIT=0;
     TMR1L=0XF0;
TMR1H=0XD8;
      TMR1ON_BIT=1;
  while(1)
  {

if(TMR1IF_BIT==1)
{
TMR1ON_BIT=0;
TMR1H=0XD8;
TMR1L=0XF0;
 RB7_BIT=~RB7_BIT;

      TMR1IF_BIT=0;
       TMR1ON_BIT=1;
} } }
 

you must write your program like that:

void interrupt() {
*/ interruption traitement
}

void main() {
}
_______________________________________________

try this for your program.

*/ -----------------------------
*/ interruption ISR
*/ -----------------------------

void interrupt() {
TMR1ON_BIT=0;
TMR1H=0XD8;
TMR1L=0XF0;
RB7_BIT=~RB7_BIT;
TMR1IF_BIT=0;
TMR1ON_BIT=1;
}

*/ -----------------------------
*/ Main
*/ -----------------------------

void main() {
TRISB=0;
PORTB=0;
GIE_BIT=1;
PEIE_BIT=1;
T1CON=0X00;
TMR1IE_BIT=0;
TMR1L=0XF0;
TMR1H=0XD8;
while(1){
}}
 

My application is to drive a servo motor so i have created 20ms delay using timer0,which is working fine and want to create 1ms-2ms delay using timer1 so here is the code for 2ms delay ,but its not working...so plz help

Code: 
unsigned int count,countt;
unsigned char output;

void interrupt()
{
  if(TMR0IF_BIT==1)
  {

    count+=1;
    TMR0IF_BIT=0;
    
  }
   if(TMR1IF_BIT==1)
  { TMR1ON_BIT=0;
  TMR1IF_BIT=0;
   
  }
  
  }
void Delay()
{
TMR1H=216;//values to generate 2ms delay for 20mhz crystal
TMR1L=240;
TMR1ON_BIT=1;
}
void main()

{


OPTION_REG=0x87;
 T1CON=0X80;
  TMR1IE_BIT=1;
  GIE_BIT=1;
  PEIE_BIT=1;
TMR0IE_BIT=1;
  TMR0=60;

  while(1)
  {


    switch(count )
    {
    case 1:
     
      RC1_BIT=1;
    
     Delay();

 RC1_BIT=0;
     
      TMR0=60;
      count=0;
      break;
}
}
}
 

I am new with PIC. And i'm trying to generate a 1sec delay using timer1 in pic16f877a

I wrote the following program, But the delay is not accurate enough. Could someone please help.


#include<htc.h>
__CONFIG(HS & PWRTEN & LVPDIS & WDTDIS & BORDIS);

void main()
{
int count =0;
TMR1ON = 1;
TMR1CS =0;
T1CKPS0=0;
T1CKPS1=0;
TMR1IF=0;
TMR1H = 0X0B;
TMR1L=0XDC;
TRISB=0X00;
RB1=0;
while(1)
{
while(!TMR1IF)
{}
count++;
if (count==16)
{
RB1=!RB1;
count=0;
}
TMR1H = 0X0B;
TMR1L=0XDC;
TMR1IF=0;
}
}
 

plz comment ur code so that I can understand how u r trying to generate delay..
 

In writing a value to a 16-bit timer, the order of the bytes is important.
Isn't this so for pic16f877a ?
 

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