// // Row pins (outputs)
// #define ROW0 0
// #define ROW1 1

// // Column pins (inputs with external pull-down)
// #define COL0 2
// #define COL1 3

// // LED pin
// #define LED 7

// void setup() {
//   pinMode(ROW0, OUTPUT);
//   pinMode(ROW1, OUTPUT);

//   pinMode(COL0, INPUT);
//   pinMode(COL1, INPUT);

//   pinMode(LED, OUTPUT);

//   // Keep rows LOW initially
//   digitalWrite(ROW0, LOW);
//   digitalWrite(ROW1, LOW);
// }

// void loop() {
//   bool keyPressed = false;

//   // -------- Scan Row 0 --------
//   digitalWrite(ROW0, HIGH);
//   digitalWrite(ROW1, LOW);

//   if (digitalRead(COL0) == HIGH || digitalRead(COL1) == HIGH) {
//     keyPressed = true;
//   }

//   digitalWrite(ROW0, LOW);

//   // -------- Scan Row 1 --------
//   digitalWrite(ROW1, HIGH);

//   if (digitalRead(COL0) == HIGH || digitalRead(COL1) == HIGH) {
//     keyPressed = true;
//   }

//   digitalWrite(ROW1, LOW);

//   // -------- LED Control --------
//   if (keyPressed) {
//     digitalWrite(LED, HIGH);
//     delay(50);   // debounce
//   } else {
//     digitalWrite(LED, LOW);
//   }
// }

#include <stdint.h>

/* ---------------- PORTA (Keypad) ---------------- */
#define PINA   (*(volatile uint8_t*)0x23)
#define DDRA   (*(volatile uint8_t*)0x24)
#define PORTA  (*(volatile uint8_t*)0x25)

#define PINB   (*(volatile uint8_t*)0x20)
#define DDRB   (*(volatile uint8_t*)0x21)
#define PORTB  (*(volatile uint8_t*)0x22)

/* ---------------- PORTH (LED) ---------------- */
#define DDRH   (*(volatile uint8_t*)0x101)
#define PORTH  (*(volatile uint8_t*)0x102)

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


volatile long i,j;


int main(){
  DDRF |= 0X0F;
  DDRB = 0X00;
  DDRA |= 0X02;

while(1){
  PORTF = 0x00;
  for(i=0; i<2; i++){
    PORTA |= (1<<i);
     PORTF = PINB;
  }
 
}
}