I'll very appreciate if you can help me with the following issue: Configured Timer 2 on P89C51RD2 . I'm getting around me and become confused from it ... So, I configure Timer 2 / 16-bit timer (the timer overflows (goes from 0xFFFF to 0x0000) An interrupt service routine (ISR) have to be invoked whan timer 2 have expired. (In which register I have to set the interrupt number void timer2_ISR (void) interrupt xx ??) Can you send me a 'C' example code which demonstrated this issue. Thanks Moshe