оформить так
inline void WDT_Start( void )
{
__watchdog_reset();
// Start timed equence
WDTCSR |= (1<<WDCE)|(1<<WDE);
// Set new prescaler(time-out) value = (~2s)
WDTCSR = (1<<WDE)|(1<<WDP2)|(1<<WDP1)|(1<<WDP0);
}
inline void WDT_Stop( void )
{
__watchdog_reset();
MCUSR &= ~(1<<WDRF);
WDTCSR |= (1<<WDCE)|(1<<WDE);
WDTCSR = 0;
}