Blinking atmega

atmega_blink.c

/* ledblink.c, an LED blinking program */
#define F_CPU 1000000UL
#include<avr/io.h>
#include<util/delay.h>

void sleep(uint8_t millisec)
{
    while(millisec)

    {
        _delay_ms(1);/* 1 ms delay */
        millisec--;
    }
}
void main()
{
    DDRB |=1<<PB0;  /* PB0 will now be the output pin */
    // DDRB = DDRB | 1<<PB0;
    // DDRB = 0xb00000001;
    while(1)
    {   
        PORTB &= ~(1<<PB0);/* PB0 LOW */
        // PORTB = 0xb00000001;
        sleep(1000);/* 100 ms delay */

        PORTB |=(1<<PB0); /* PB0 HIGH */
        // PORTB = 0xb00000000;
        sleep(1000);/* 100 ms delay */
    }
}