I am an old assembler guy, just getting started in C using CodeWarrior 10.6.4 on an MC9S08QB8 device. I have had the target up and running using an assembly program, but now I wish to try changing over to C. A simple sample program is shown below in the IDE debugger. The code is supposed to set up a 10mSec Modulo Timer and just toggle a microprocessor pin high/low on each 10mSec interrupt. I am getting two syntax errors: one on the Initialize_CPU call, (with that routine also shown), and the other on the ISR for my Modulo Timer. The ISR format was taken from NXP/Freescale's "HCS08QRUG Rev. 1" document in the "Implementing Interrupt Service Routines" section. Does anyone know why I'm getting the Syntax Errors? Does either syntax error deal with the need for Function Prototypes that I've seen, like in C++ ? Also, if I were to have several separate .c source files, is there anything I need to do to allow one source file to "see" the functions in the other source files?