Hi Henrik,
yes, I must have left off the "return" or something, trying again it worked fine. But since I put the defines for the seperate file related variables in that file ( for example the tx and rx variable names etc) , then that "include" had to be left at the top of the main.
Calls to subroutines on that file do work, but I am wondering where those routines get placed into the compiled program or mabye it doesn't matter ?

don