// connect 8 leds to port A glow the leds in this order 37,26,15,04
#include <stdint.h>

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

void delay1sec(void){
    TCNT1 = 0;        
    TCCR1A = 0x00;    
    TCCR1B = 0x05;   

    while (TCNT1 < 15625); 

    TCCR1B = 0x00;   
}

void setup() {
  // put your setup code here, to run once:
  DDRA |= 0xff;
}
int i;
int port(int i){
  
  PORTA |= (1<<i) | (1<<(i+4));
  delay1sec();
  PORTA &= ~((1<<i) | (1<<(i+4)));
  delay1sec();
}
void loop() {

for(int i=0; i<4; i++){
  port(i);
}

}