#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;

 uint8_t seg[10] = {
    0x3F,
    0x06,
    0x5B,
    0x4F,
    0x66,
    0x6D,
    0x7D,
    0x07,
    0x7F,
    0x6F
};


int keymap[4][4] = {
    {1, 2, 3, -1},
    {4, 5, 6, -1},
    {7, 8, 9, -1},
    {-1, 0, -1, -1}
};


int column(void)
{
    if (PORTK & (1<<0)) return 0;
    if (PORTK & (1<<1)) return 1;
    if (PORTK & (1<<2)) return 2;
    if (PORTK & (1<<3)) return 3;
    return -1;   // no column pressed
}

void setup() {
  DDRF = 0XFF;
  DDRK = 0X00;
  DDRA = 0XFF;

}

void loop() {

   for(i=0; i<4; i++){
    PORTF = (1<<i);  //Port f matrix row giving supply port k is reading pin
    int col = column();
    if(PORTK != 0){
      PORTb = (1<<i); //for display ing row 
    int digit = keymap[i][col];
    PORTA = seg[digit];
   
    PORTb = 0;
    }
    
   }


}