Can anyone else verify that the Hello example fails to output to the serial#1 window when the reg515a.h is included. Single stepping through the program I can see the characters being written to SBUF but nothing is displayed in serial#1. Just by replacing the statement "#include <reg515a.h>" with say "#include <reg552.h>" the program works just fine.
Have you tried turning on all the compiler listing options - preprocessor output, #included files, assembler, etc - and all the Linker listing options, and then doing a side-by-side text compare on the listings using the 2 different #include files? That might reveal a clue? we recommend Araxis Merge as a text comparison tool (and musch more): http://www.araxis.com/
Thanks for all your help. I just created a new project and brought over my .c and .h files. It occured to me that it could have been a corrupted include file, so I copied over a new reg515a.h from the keil web site. It works now.
Do you know if it was a corruption in your file, or was there an error which Keil have fixed in the latest version?