Atmel printf formatting doesn't work, no formatting does work
Have you tried creating a character buffer, formatting it, and then printing it?

   char buffer [50];
   int A = 12;
   i = sprintf (buffer, "A: %d \n", A);

   printf(buffer);


Also, try initializing the variable first, then include it inside the printf.

   int A = 12; 
   printf("number: %d \n", A);