Actually on the external interrupt from port,I want to read the timer 2 value into a variable.(TH2 and TL2). suppose I declare a variable unsigned int timer2_val; How can I move TL2 and TH2 into lower and upper nibble of timer2_val, so that I can treat Timer2 value as a single variable. Weather keil has any declaration for assigning the lower byte or higher byte of a unsigned int to any hardware register or something like that. I am a beginner in C. Cygnalroy