// Useful info:
// On my board, LED 1 is on PA2
//              LED 2 is on PA3
//              BUTTON 1 is on PA7
//              BUTTON 2 is on PB2

#include <avr/io.h>

#define led_pin_1 (1 << PA2)
#define led_pin_2 (1 << PA3)

int main(void) {
    // Configure led pins as an output.
    DDRA |= led_pin_1;
    DDRA |= led_pin_2;

    // Set led pins high.
    PORTA |= led_pin_1;
    
    // Nothing left to do, so just spin.
    while (1) {
      PORTA ^= led_pin_1;
      PORTA ^= led_pin_2;
      for (long i = 0; i < 100000; ++i) {
      }
    }
    return 0;
}