Dear Colleagues, I need your suggestions. I need to use printf feature and I have not had luck with uVision. I did this: I copied to my folder project and modified the putchar.c then I added it to my project window. When everything was ok I compiled it and the systems said a fatal error occured. I wonder if the systems needs the putchar obj before compiling. Who can give me a hand? who has a complete putchar file? or send me a complete project example to opiedrahita2003@yahoo.com Appreciate your help. Thanks