gistfile1.c

static inline void  bootLoaderInit(void)
{
    PORTB |= (1 << 5);
    PORTD |= (1 << JUMPER_BIT);     /* activate pull-up */
    if(!(MCUCSR & (1 << EXTRF)))    /* If this was not an external reset, ignore */
        leaveBootloader();
    MCUCSR = 0;                     /* clear all reset flags for next time */
}