Conver char value to variable?
Ok, first, char varAT[12] indicates an array of 12 characters. 

Second, quotes indicate literals - 'A' means, literally, the character 'A'. Variables and constants are without quotes (same way you use  i).

I think you mean:

char *varAT[12]={A,B....};


Also, your constant B is invalid - I think you meant for it to end in \r", not \".