#include <stdint.h>

#define DDRA  (*(volatile uint8_t*)0x21) //led
#define PORTA (*(volatile uint8_t*)0x22) //output

#define DDRb  (*(volatile uint8_t*)0x24) //led
#define PORTb (*(volatile uint8_t*)0x25) //output

#define DDRF  (*(volatile uint8_t*)0x30) //keypad
#define PORTF (*(volatile uint8_t*)0x31) //output

#define DDRK  (*(volatile uint8_t*)0x107)  //leypad
#define PORTK (*(volatile uint8_t*)0x106) //input
 uint8_t i,j;
void setup() {
  DDRF = 0XFF;
  DDRK = 0X00;
  DDRA = 0XFF;

}

void loop() {
   for(i=0; i<4; i++){
    PORTF = (1<<i);  //Port f matrix row giving supplu port k is reading pin
    PORTA = PORTK;  //port a is led connected pin
    
    if(PORTK != 0){
      PORTb = (1<<i); //for display ing row 
   
    PORTb = 0;
    }
    
   }


}