Timer0

#include <16F887.h>         

#USE DELAY(clock=400000000)
               
#FUSES INTRC,NOWDT,NOPUT,NOMCLR,NOPROTECT,NOCPD,NOBROWNOUT,NOIESO,NOFCMEN,NOLVP

#byte porta=0x07
#byte portb=0x06
#byte portd=0x08

void main()
{
   
   int val;

   set_tris_a(0xff); //porta all input
   set_tris_b(0xff); //portb all input
   set_tris_d(0x00); //portd all output

   setup_adc_ports(no_analogs);
   
   val=1;
   
   portd=0;
   
   for(;;){
      delay_us(500);
      val++;
      portd=val;
   }
}