[time-nuts] Automatic switching of a µC osc. to external 10MHz reference as clock?

[Peter Krengel]

Hello guys,

I'm looking for a possibility to make an automatic switching
between the internal µC oscillator (Atmel µC) to the 10MHz output
of my thunderbolt to use it as a precise µC clock. Has anybody an idea how 
to do best
without disturbing the accuracy of the ref. signal?

Thank you in advance
Peter, DG4EK