Happy New Year to everybody!

First of all,I want to tell Michael Karas that I sol-
-ved the read and write at24c01 using 2 assembler
routines from a friend of mine.
The problem which I have now is that:in my RTC I
want to programm YEAR,MONTH,DAY from the keyboard
and I used "scanf",but using "scanf",the programm
hang-on,nothing happens;without "scanf" everything it's o.k.!
Instructions are like this:
printf("write YEAR:");
scanf("%bu",&YEAR);
printf("%bu",YEAR);
Can anybody tell me what is wrong with "scanf"?
YEAR is un unsigned char.
Thanks,
Stefan