Analog reading whit registers

[alto777]

@JohnRob

 void loop() {  
  //REFS1 AND REFS0 to 1 1 -> internal 1.1V refference
  ADMUX |= B11000000;   
  //We read A2 (MUX0)
  ADMUX |= B0000100;      
 

My guess is the second assignment to ADMUX negates the first.

Guess (or look) again. Those are compound assignment operators. So same as

ADMUX = ADMUX | B11000000;
ADMUX = ADMUX | B0000100;

@penispena I see the second constant is only 7 bits, is the correct bit being set in the second assignment?

a7