Code:

static void usbReset(void)
{
    usbDeviceDisconnect();  /* enforce re-enumeration, do this while interrupts are disabled! */
   uchar i = 0;
    while(--i){                // USB disconnect for >250ms
        _delay_ms(1);
    };
    usbDeviceConnect();
}

Code:

static void blinkLed(int n_times)
{
if (n_times == 0 )  return;
char i;
DDRC |= 0x08;
   LED_OFF();
   while (n_times--)
   {
      LED_ON();
      for (i=0; i<1; i++) _delay_ms(1000);
      LED_OFF();
      for (i=0; i<1; i++) _delay_ms(1000);
   }   

}

Code:

int main(void)
{
uchar   i;
   
   DDRC |= 0x08;

     blinkLed(5);   /* <---------------------- it's blinking time */

     wdt_enable(WDTO_1S);
    /* Even if you don't use the watchdog, turn it off here. On newer devices,
     * the status of the watchdog (on/off, period) is PRESERVED OVER RESET!
     */
 //   DBG1(0x00, 0, 0);       /* debug output: main starts */
    /* RESET status: all port bits are inputs without pull-up.
     * That's the way we need D+ and D-. Therefore we don't need any
     * additional hardware initialization.
     */
    odDebugInit();
    usbInit();
    usbDeviceDisconnect();  /* enforce re-enumeration, do this while interrupts are disabled! */
    i = 0;
    while(--i){             /* fake USB disconnect for > 250 ms */
        wdt_reset();
        _delay_ms(1);
    }
    usbDeviceConnect();
    sei();
 //   DBG1(0x01, 0, 0);       /* debug output: main loop starts */
    for(;;){                /* main event loop */
 //       DBG1(0x02, 0, 0);   /* debug output: main loop iterates */
        wdt_reset();
        usbPoll();
     }
    return 0;
}

Code:

#define LED_OFF() do { PORTD |= 0x20; } while(0)
#define LED_ON() do { PORTD &= ~0x20; } while(0)


static void blinkLed(int n_times)
{
if (n_times == 0 )  return;
char i;
DDRD |= 0x20;
   LED_OFF();
   while (n_times--)
   {
      LED_ON();
      for (i=0; i<20; i++) _delay_ms(10);
      LED_OFF();
      for (i=0; i<50; i++) _delay_ms(10);
   }   

}

Code:

    for(;;){                /* main event loop */
 //       DBG1(0x02, 0, 0);   /* debug output: main loop iterates */
        wdt_reset();
        usbPoll();
      if(led_on == 1) {
         PORTC &= ~_BV(4);  // turn LED off
         led_on = 0;
         _delay_ms(1000);   // delay 1 second
      }else{
         PORTC |= _BV(4);   // turn LED on
         led_on = 1;
         _delay_ms(1000);
      }
    }
    return 0;

Code:

#define F_CPU 12000000L
#include <avr/io.h>
#include <util/delay.h>

int main(void)
{
   int led_on = 0;
   DDRC = 0x08; // configure output on pin 3

   while(1)
   {
      PORTC |= 0x08;  // output voltage on pin 3
      _delay_ms(1000);
      PORTC &= ~0x08;  // clear voltage on pin 3
      _delay_ms(1000);
   }
    return 0;
}