10 POKE 56579,15:REM SETS PB0-PB3 TO OUTPUT, PB4-PB7 TO INPUTS
15 POKE56578,PEEK(56578)OR 4 :REM PA2 IS MADE AN OUPUT
20 FOR B=0 TO 15
30 POKE56577,B:REM GENERATES BINARY COUNT ON PB0-PB3
40 A=PEEK(56577)AND 16:REM SENSES STATE OF INPUT SELECTED BY COUNT
45 IF A=16 AND B=15 THEN 90: REM JUMP TO DELAY IF ALARM WAS TRIGGERED BY SW 15
50 IF A=16 THEN POKE 56576,PEEK(56576)AND251:REM ALARM HAS BEEN TRIGGERED
55 IF A=16 THEN END
60 NEXT B
70 GOTO 20
90 FOR C=1 TO 50000:NEXT C: REM DELAY FOR NORMAL ENTRANCE
100 GOTO50