// pattern 7,76,765,7654,76543,765432,7654321,76543210

//0,01,012,0123,01234,.....01234567

#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() {
    DDRA = 0xFF;
}

void loop() {
    for (uint8_t i = 7; i >=0; i--) {
      PORTA |= (1<<i);
      delay1sec();
    }
}