After a long time I,m posting an SOS update. Its not that I had abandoned the project (which is impossible) but the software multitasking support did give me some sleepless noons ;). It practically drove me crazy. Debugging stack problems without debugger is no joke. But finally I, persistent as always, cracked it. Now I have 2 tasks and a round robin scheduler. Working like a charm. Its still spaghetti code that I have to re-write but main part is done. Tonight I will sleep peacefully :)