to call subroutine after setting my settable value in variable to my main logic's each condition

hey

i have 3 subprogram
1--main logic
2--time updation by timer/interupt
3----sttable time value in variable by four button

when i am setting time value as by my 3 Sub program, timer start for my seetable time ,
but same should be call for main logic condition.as my logic work true even after time.