07_AVR_LED_BLinking_RingCounter.c

#include <avr/io.h>
#include <util/delay.h>

int main()
{
    char count = 1;
    DDRC = 0xff;           // Configure PORTC as output

    while(1)
    {
        PORTC = count;     // Display Counter value on LEDs
        _delay_ms(200);    // Wait for some time

        count = count<<1;   // Left shift the bit to generate ring counter

        if(count == 0)      // If counter reaches zero then set it back to 1;
            count = 0x01;
    }
    return 0;
}