Implement the algorithm to dynamically determine the boundary values as described in 2a8e6472cd0aa12fee8b363c231b4c0430061866
Implement the algorithm to dynamically determine the boundary values as described in 2a8e6472cd0aa12fee8b363c231b4c0430061866

The difference with readpin.c is that maxone is updated once per second
instead of once per minute, giving a faster response in case of sudden
changes to realfreq.

Drop the case that tlow /t  is uninitialized.

rene0/dcf77pi,rene0/dcf77pi