Several strange things here (but you should have posted your example as code too).

Your formatting strings starts with " r " - there should have been a " r " in the output - before the date/time.

Your formatting string ends with a " n". It should have ended with a "n" to signal a new line.

Putchar contains the line:

if ( c == 'n')

But the line should have looked like:

if (c == 'n')

Are you sure that you have copied - and not retyped - the code from the Keil application note? There may be other errors too.

And have you made sure that OLEN has a value of 2^n, where n is >= 1? If not, the expression "outbuf[oend++ & (OLEN-1)]" will not work as expected. OLEN must be a number that in the binary number system starts with a one, and is followed by one or more zeros, i.e. 2, 4, 8, 16, 32, ... This makes sure that (OLEN-1) will be a binary value containing a continuous sequence of ones.