My somewhat outdated CCS compiler does delays using NOPs in a loop, not=20
a timer.  Also, the 877 has no internal oscillators.

Since you don't enable interrupts (and they default to 'off'), it seems=20
to me it can only be 2 things:

1)  The debugger is using a LOT of time (seems unlikely)

2)  The oscillator is not really running at 4MHz.

Try running without the debugger (config=3D0F09), because that's easy.
If that doesn't do it, write your own delay

ms_delay(int d)  // Only works with 4MHz clock!!!
{
    for(i=3D0;i<d;i++)
    {
       for(j=3D0;j<100;j++)
       {
          #asm
             nop
             nop
             nop
             nop
             nop
             nop
             nop
             nop
             nop
             nop
       #endasm
       }
    }
}

If that gives you the correct delay, the problem is the delay_ms()=20
routine, otherwise, it is the clock frequency.

Kerry

geetansh arora wrote:
> sorry i missed some details which might be important in solving this
> problem.
>
> I started with my first project but it didn't worked so i decided to go b=
ack
> and blink leds,now the problem is when the delay between on off  was set
> 10ms the leds took 2.3sec(used a stopwatch n delay was approx. 2.3sec).
> At first delay was set to 500ms but it took too much time to blink so del=
ay
> was set to 10ms.
> CCS compiler demo version was used for compiling , 4MHz crystal oscillato=
r
> was used with 22pF capacitors and configuration bits 2F09 were entered in
> PICKIT 2 v2.61 (not used in the code)
>
> #include <16F877A.h>
> #use delay(clock=3D4000000)
> void main()
> {
> while(1)
> {
> output_D(255);
> delay_ms(10);
> output_D(0);
> delay_ms(10);
> }
> }
> please solve my problem guys.
> thank you and sorry again for missing the details in previous post.
>  =20

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.