I'm using an 8051/8052 emulator build with Siemens 80c535 uc, and i use uvision2 v2.31 to put the program in. This is a student version of uVision and i'm using it for educational purpose. my goal is to develop a system with serial communication. Problem is that when i try to emulate function printf my emulator is blocked, but on the other hand same thing works with function putchar(printf use putchar). Emulator was build under old version of uVision that worked under DOS and the function printf worked properly. Thnx!