I want to use the ARM CMSIS DSP library on the k28 board I am using. I've got everything building and running but there is something strange happening with printf. I enable SWO on the board and compile in retarget_itm.c. However, I only ever get the first printf on the SWO ITM console. If I place a breakpoint in _write, it will enter it once but never again. The program continues to run just fine but no output on the console. I't like the link to _write got lost so calls to printf never show up again.