#define  led1    portb.f1
#define  led2    portb.f2
#define  led3    portb.f3
////////////////////////////
int i,x;
////////////////////////////
void interrupt(){
x+=1200;
if(x>3600)x=0;
if(x==1200)led1=1;
if(x==2400)led2=1;
if(x==3600)led3=1;
delay_ms(250);
intcon.f1=0;
                 }
/////////////////////////////
void main() {
portb=0;
trisb=1;
intcon=144;
option_reg=63;
while(1){x=0;
         delay_ms(250);
         for(i=0;i<x;i++)
             delay_ms(250);
         led1=0;
         led2=0;
         led3=0;
         }
             }
//////////////////////////////

/*****************************************************************
PIC16f628A
Externally CRYSTAL 4000.000HZ
timer0

*******************************************************************/
unsigned short  Counter , minute, led=0 ;

//Timer0
//Prescaler 1:256; TMR0 Preload = 60; Actual Interrupt Time : 49.92 ms

//Place/Copy this part in declaration section
void InitTimer0(){
  OPTION_REG	 = 0x87;
  TMR0		 = 60;
  INTCON	 = 0xA0;
}


void Interrupt(){   //ISR
  if (TMR0IF_bit){
    TMR0IF_bit	 = 0;
    TMR0		 = 60;
  Counter++;  //  increment count
  }
}

void main() {


InitTimer0();

trisa.f0=1;    //pin input for button
trisb.f0=0;   // pin output for led_1
trisb.f1=0;   // pin output for led_2
trisb.f2=0;   // pin output for led_3
trisb.f3=0;   // pin output for led_4

portb.f0=0;   // led_1 is off
portb.f1=0;   // led_2 is off
portb.f2=0;   // led_3 is off
portb.f3=0;   // led_4 is off

while (1){



 if (Counter == 255)
 {
  Counter=0;minute++;  // 12.8  second
 }

 
       if (RA0_bit) {                    // button on RA0 pressed
      Delay_ms(600);
      Counter=0;
      minute=0;
      led++;
     }
      if (led == 1)

        {portb.f0=1;if(minute==24){led=0;}}   // led 1 on 5min
        
      if (led == 2)

        {portb.f0=1;portb.f1=1;if(minute==48){led=0;}}   // led 1&2 on 10min
        
      if (led == 3)

        {portb.f0=1;portb.f1=1;portb.f2=1;if(minute==72){led=0;}}   // led 1&2&3 on 15min
        
      if (led == 4)

        {portb.f0=1;portb.f1=1;portb.f2=1;portb.f3=1;if(minute==96){led=0;}}  // led 1&2&3&4 on 20min
        
      if (led == 5)
        {led = 1 ;portb.f1=0;portb.f2=0;portb.f3=0;}  // led 1 on 5min & led 2&3&4 off

       if(led==0)
       {portb.f0=0;portb.f1=0;portb.f2=0;portb.f3=0;} //  led 1&2&3&4 off
         


        }
}