Hi Puls thanks for the answer, you you are right, sorry, misunderstanding.
DDRC = B00000001; // use analog 0 as digital OUTPUT
PORTC = B00000001; //use analog 0 as digital set to HIGH
Ok it works I can see a LED on and off, seems works...
But, i can't understand why if I use the two lines shown before instead of:
pinMode(A0, OUTPUT);
digitalWrite(A0, HIGH);
My code don't works, i get null / crappy characters...
Is there some difference in the two codes shown??
I am killed by this different result...