ATmega88 @ 8MHz 15

atmega88-15.c

/* code015.c ATmega88 @ 8MHz */
#include <avr/io.h>
 
uint32_t counter = 100000;
 
int main(void)
{
    DDRD = 0xFF;
    PORTD = 0x00;
     
    asm ("WDR");    // watchdog reset
     
    WDTCSR = (1<<WDCE)|(1<<WDE);                        // watchdog change enabled
    WDTCSR = (1<<WDE)|(1<<WDP0)|(1<<WDP1)|(1<<WDP2);    // watchdog system reset enabled,
     
    // set timeout 2s
    asm ("NOP");    // no operation
     
    while(1)
    {
        while (counter >= 1)
        {
            counter --;
            PORTD = (1<<PD7); // LED ON
        }
        asm ("WDR");            // watchdog reset
        counter = 100000;
    }
}