du meinst so ?

Code:
#pragma vector=INT0_vect
__interrupt void ext_int0(void)
{
  if(!(bRxFlag & RX_M_RECEIVE))
  {
  GICR = 0;                     // Disable external interrupt
  bTxFlag &= ~TX_M_SEND;        // Deactivate Transmit-Mode
  bRxCount = 0;                 // Clear Receive Counter
  TIFR |= (1<<TOV0);            // clear T/C0 overflow flag

  TIMSK |= (1<<TOIE0);          // enable T/C0 overflow interrupt
  TCNT0 = INT0_PRELOAD;         // Set timer reload-value (to 1.5 bit len). 29 = time delay that
			        // have already been used in this
			        // interrupt plus the time
			        // that will be used by the time
			        // delay between timer interrupt request
			        // and the actual sampling of the first
			        // data bit.
  bRxFlag |= RX_M_RECEIVE;      // Activate Receive-Mode
  }
}
edit: funkt trotzdem noch nicht