Hi all; I am using AT89S8252 device and Keil's C-language compiler. I have a 5.7 kb long program. Whenever user presses a button connected to External int 0, the control passes to INT_0_ISR I want to allways return back from ISR to a label 'option'. While the ISR normally will return to where it was interrupted. How can I achieve this please? - arun
Either do all the work in the interrupt handler, or just note the event and sufficient information for some later processing outside of the interrupt. Third option - put the processing in a low-priority ISR and set the appropriate interrupt before leaving the first ISR.