#include <16F84A.h>                      // Pic Model 16F84A

#fuses XT,NOWDT,NOPROTECT,PUT

#use delay(clock=4000000)        // Crystal Oscillator Frequency

#define phase1 0x04
#define phase2 0x10
#define phase3 0x08
#define phase4 0x20

#define portB 0x06

int cont=0;

#INT_EXT
void INT_EXT_isr ()
{
   if(!input(PIN_B1))
   {
      cont ++;
      if(cont == 4) {
         cont=0;
      }
   }
   else
   {
      if(cont==0)
      {
         cont = 4;
      }
      cont--;
   }
   
   switch(cont) {
      case 0 : 
      #asm
      movlw phase1
      movwf portB
      #endasm
      break;
      case 1 : 
      #asm
      movlw phase2
      movwf portB
      #endasm
      break;
      case 2 : 
      #asm
      movlw phase3
      movwf portB
      #endasm
      break;
      case 3 : 
      #asm
      movlw phase4
      movwf portB
      #endasm
      break;
   }
   delay_us(100);
}

//about 250ms 114 = 1sec
#define HIGH_START 28
byte seconds, high_count;

#INT_RTCC

clock_isr() {
   if(--high_count==0) {
    #asm
      movlw 0x00
      movwf portB
     #endasm 
      high_count=HIGH_START; 
   } 
}


void main(void)
{
   set_tris_b(0x03);
   enable_interrupts(GLOBAL);
   enable_interrupts(INT_EXT); 
   
   set_rtcc(0);
   setup_counters(RTCC_INTERNAL, RTCC_DIV_128); 
   enable_interrupts(INT_RTCC); 
   high_count=HIGH_START;


   ext_int_edge(L_TO_H);
   //set all phases to 0 by default
   #asm
      movlw 0x00
      movwf portB
   #endasm   
   while(1);
}