I am using At89s8252 to develope my project. and i have some difficult now. I need to set the following things, 1. Timer 0 and a time ticker 2. SPI port for serial interfancing 3. Serial port for data transmission. I have no problem for each sub-program, However, when i combin it together in pne prooject, i find that the timer 0 have noo respose. What should i do ?