sub routine question

[emmett brown]

Does a subroutine stop everything like a pause would if it were in the main program? I need ,while running the hpwm code to check continuity on a level sensor every 15 minutes or so then turn an LED on. What would be the best way to do this? Also what would be the best serial LCD that will monitor what's going on in my program and still allow pins for ADC/HPWM/ inputs ETC? 16F877 at 4 Mhz. It would need to be pretty stupid proof as in easy instructions as in pin out's and pre-canned code cause I shouldn't be getting this complicated with this, but that's the way I am! Thanks much, this group is excellent - well worth the cost of PBP!