Yes, Sonabouy, I've already done, the nois-interruption takes
all power in uP, but as I have heared from people with experience
from this type of sofware, it always do.

As I wrote erlier, now I have to samples and estimate the results
of locked & approved squarewave-signal in the interrupt-routine.

Start to use a LED as lock detect during develoop software.

Other funktion as check ports and setting ports, I'l solve with external
interrupt 1.

As far as the uP have to do anything else, it have to abandon the
listening-mode during that time.

There is no other way. :)